The effects of 5 lactic acid bacteria(LAB)fermentation on the pasting properties of glutinous rice flour were compared,and suitable fermentation strains were selected based on the changes of viscosity,setback value,an...The effects of 5 lactic acid bacteria(LAB)fermentation on the pasting properties of glutinous rice flour were compared,and suitable fermentation strains were selected based on the changes of viscosity,setback value,and breakdown value to prepare LAB compound starter cultures.The results revealed that Latilactobacillus sakei HSD004 and Lacticaseibacillus rhamnosus HSD005 had apparent advantages in increasing the viscosity and reducing the setback and breakdown values of glutinous rice flour.In particular,the compound starter created using the two abovementioned LAB in the ratio of 3:1 had better performance than that using a single LAB in improving the pasting properties and increasing the water and oil absorption capacity of glutinous rice flour.Moreover,the gelatinization enthalpy of the fermented samples increased significantly.For frozen glutinous rice dough stored for 28 days,the viscoelasticity of frozen dough prepared by compound starter was better than that of control dough,and the freezable water content was lower than that of control dough.These results indicate that compound LAB fermentation is a promising technology in the glutinous rice-based food processing industry,which has significance for its application.展开更多
Food allergy as a global health problem threatens food industry.Bee pollen(BP)is a typical food with allergenic potentials,although it performs various nutritional/pharmacological functions to humans.In this study,lac...Food allergy as a global health problem threatens food industry.Bee pollen(BP)is a typical food with allergenic potentials,although it performs various nutritional/pharmacological functions to humans.In this study,lactic acid bacteria(LAB)were used to ferment Brassica napus BP for alleviating its allergenicity.Four novel allergens(glutaredoxin,oleosin-B2,catalase and lipase)were identified with significant decreases in LAB-fermented BP(FBP)than natural BP by proteomics.Meanwhile,metabolomics analysis showed significant increases of 28 characteristic oligopeptides and amino acids in FBP versus BP,indicating the degradation of LAB on allergens.Moreover,FBP showed alleviatory effects in BALB/c mice,which relieved pathological symptoms and lowered production of allergic mediators.Microbial high-throughput sequencing analysis showed that FBP could regulate gut microbiota and metabolism to strengthen immunity,which were closely correlated with the alleviation of allergic reactivity.These findings could contribute to the development and utilization of hypoallergenic BP products.展开更多
In this study,a new type of 3 D printed living biological hydrogel was developed by integrating lactic acid bacteria(LAB)into biocompatible and non-toxic polymer materials.Interestingly,the living materials loaded wit...In this study,a new type of 3 D printed living biological hydrogel was developed by integrating lactic acid bacteria(LAB)into biocompatible and non-toxic polymer materials.Interestingly,the living materials loaded with LAB can be freeze-dried and reused for more than 100 times.The bio-hydrogel can be used to co-culture different LAB and keep its fermentation performance stable in long-term use.The release kinetics model and response surface method were used to simulate and optimize the bacteria release mode in the bio-hydrogel.The results show that the release of bacteria from hydrogel is regulated by the coupling of Fickian diffusion and polymer swelling.The stability of LAB hydrogel was evaluated by reuse experiments.The images of confocal microscopy and scanning electron microscope showed that the bacteria with high cell viability were distributed in the hydrogel and intact structure of the living hydrogel was maintained after 100 times of reuse as yoghurt starter.In conclusion,the 3 D printed LAB bio-hydrogel developed in this study has the advantage of reuse and sustainability,which is expected to open up a new way for the preparation of food culture starter.展开更多
This study was conducted to evaluate the effect of lactic acid bacteria and propionic acid on the fermentation quality, aer- obic stability and in vitro gas production kinetics and digestibility of whole-crop corn bas...This study was conducted to evaluate the effect of lactic acid bacteria and propionic acid on the fermentation quality, aer- obic stability and in vitro gas production kinetics and digestibility of whole-crop corn based totalmixed ration (TMR) silage. Total mixed ration was ensiled with four treatments: (1) no additives (control); (2) an inoculant (Lactobacillus plantarum) (L); (3) propionicacid (P); (4) propionic acid+lactic acid bacteria (PL). All treatments were ensiled in laboratory-scale silos for 45 days, and then subjected to an aerobic stability test for12 days. Further, four TMR silages were incubated in vitro with buffered rumen fluid to study in vitro gas production kinetics and digestibility. The results indicated that all TMR silages had good fermentation characteristics with low pH (〈3.80) and ammonia nitrogen (NH3-N) contents, and high lactic acid contents as well as Flieg points. Addition of L further improved TMR silage quality with more lactic acid production. Addition of P and PL decreased lactic acid and NH3-N contents of TMR silage compared to the control (P〈0.05). After 12 days aerobic exposure, P and PL silages remained stable, but L and the control silages deteriorated as indicated by a reduction in lactic acid and an increase in pH, and numbers of yeast. Compared to the control, addition of L had no effects on TMR silage in terms of 72 h cumulative gas production, in vitro dry matter digestibility, metabolizable energy, net energy for lactation and short chain fatty acids, whereas addition of PL significantly (P〈0.05) increased them. L silage had higher (P〈0.05) in vitro neutral detergent fiber digestibility than the control silage. The results of our study suggested that TMR silage prepared with whole-crop corn can be well preserved with or without additives. Furthermore, the findings of this study suggested that propionic acid is compatible with lactic acid bacteria inoculants, and when used together, although they reduced lactic acid production of TMR silage, they improved aerobic stability and in vitro nutrients digestibility of TMR silage.展开更多
This study assessed the effects of lactic acid bacteria(LAB), cellulase, cellulase-producing Bacillus pumilus and their combinations on the fermentation characteristics, chemical composition, bacterial community and i...This study assessed the effects of lactic acid bacteria(LAB), cellulase, cellulase-producing Bacillus pumilus and their combinations on the fermentation characteristics, chemical composition, bacterial community and in vitro digestibility of alfalfa silage. A completely randomized design involving a 8(silage additives)×3 or 2(silage days) factorial arrangement of treatments was adopted in the present study. The 8 silage additive treatments were: untreated alfalfa(control); two commercial additives(GFJ and Chikuso-1); an originally selected LAB(Lactobacillus plantarum a214) isolated from alfalfa silage; a cellulase-producing Bacillus(CB) isolated from fresh alfalfa; cellulase(C); and the combined additives(a214+C and a214+CB). Silage fermentation characteristics, chemical composition and microorganism populations were analysed after 30, 60 and 65 days(60 days followed by exposure to air for five additional days). In vitro digestibility was analysed for 30 and 60 days. Compared with the other treatments, selected LAB a214, a214 combined with either C or CB, and Chikuso-1 had the decreased(P<0.001) pH and increased(P<0.001) lactic acid concentrations during the ensiling process, and there were no differences(P>0.05) among them. Fiber degradation was not significant(P≥0.054) in any C or CB treatments. The a214 treatment showed the highest(P=0.009) in vitro digestibility of dry matter(595.0 g kg–1DM) after ensiling and the highest abundance of Lactobacillus(69.42 and 79.81%, respectively) on days 60 and 65, compared to all of other treatments. Overall, the silage quality of alfalfa was improved with the addition of a214, which indicates its potential as an alfalfa silage inoculant.展开更多
The objective of this study was to investigate the effect of lactic acid bacteria(LAB) inoculums on fermentation quality and in vitro digestibility of corn stover silage.Corn stover was ensiled without(control) or wit...The objective of this study was to investigate the effect of lactic acid bacteria(LAB) inoculums on fermentation quality and in vitro digestibility of corn stover silage.Corn stover was ensiled without(control) or with Lactobacillus plantarum(LP),Enterococcus faecalis(EF),and Enterococcus mundtii(EM) for 45 days.The fermentation characteristics were assessed,and subsequent in vitro dry matter digestibility(DM-D),neutral detergent fiber digestibility(NDF-D),volatile fatty acids(VFA),methane(CH4) production,cellulolytic bacteria proportions and their activities per corn stover silage were also determined.There was no significant difference(P>0.05) among the silage pH,lactic acid,crude protein(CP),water soluble carbohydrates(WSC) and lignocelluloses contents of different treatments.The relative proportions of Ruminococcus flavefaciens and Fibrobacter succinogenes,carboxymethyl-ocellulose and β-glycosidase activities,DM-D,NDF-D,and VFA production of in vitro incubation was higher(P<0.05) for silages inoculated with LP and EF than those of the control silage.Silage inoculated with LP showed the lowest(P<0.05) CH4 production per unit yield of VFA,which was positively corresponded to the lowest(P<0.05) ratio of acetate to propionate.In summary,the ensiling fermentation quality and subsequent utilization of corn stover silage were efficiently improved by inoculated with L.plantarum.展开更多
According to the sequence of the bile salt hydrolase (BSH) gene of Bifidobacterium and the restriction enzyme cutting sites of expression vector pNZ8148, primers were designed and the bile salt hydrolase (BSH) gen...According to the sequence of the bile salt hydrolase (BSH) gene of Bifidobacterium and the restriction enzyme cutting sites of expression vector pNZ8148, primers were designed and the bile salt hydrolase (BSH) gene was gotten from Bacillus bifidus ATCC 29521 by PCR. BSH gene was inserted into lactic acid bacteria expression vector pNZ8148 to construct the recombinant pNZ8148-BSH. The recombinant pNZ8148-BSH was transferred into lactic acid bacteria NZ9000 with electrotransformation method. And the recombinant which could express BSH protein was obtained. It was identified by SDS-PAGE electrophoresis and activity verification. The result could provide a rationale reference for expressing BSH in lactic acid bacteria.展开更多
Tuberculosis(TB) is a communicable disease caused by Mycobacterium tuberculosis(M. tuberculosis). WHO estimated that 10.4 million new(incident) TB cases worldwide in year 2016. The increased prevalence of drug resista...Tuberculosis(TB) is a communicable disease caused by Mycobacterium tuberculosis(M. tuberculosis). WHO estimated that 10.4 million new(incident) TB cases worldwide in year 2016. The increased prevalence of drug resistant strains and side effects associated with the current anti-tubercular drugs make the treatment options more complicated. Hence, there are necessities to identify new drug candidates to fight against various sub-populations of M. tuberculosis with less or no toxicity/side effects and shorter treatment duration. Bacteriocins produced by lactic acid bacteria(LAB) attract attention of researchers because of its "Generally recognized as safe" status. LAB and its bacteriocins possess an effective antimicrobial activity against various bacteria and fungi. Interestingly bacteriocins such as nisin and lacticin 3147 have shown antimycobacterial activity in vitro. As probiotics, LAB plays a vital role in promoting various health benefits including ability to modulate immune response against various infectious diseases. LAB and its metabolic products activate immune system and thereby limiting the M. tuberculosis pathogenesis. The protein and peptide engineering techniques paved the ways to obtain hybrid bacteriocin derivatives from the known peptide sequence of existing bacteriocin. In this review, we focus on the antimycobacterial property and immunomodulatory role of LAB and its metabolic products. Techniques for large scale synthesis of potential bacteriocin with multifunctional activity and enhanced stability are also discussed.展开更多
To improve the nutritional value and the palatability of air-dried rice straw, culture broth of the lactic acid bacteria community SFC-2 was used to examine the effects of two different treatments, fermentation and ad...To improve the nutritional value and the palatability of air-dried rice straw, culture broth of the lactic acid bacteria community SFC-2 was used to examine the effects of two different treatments, fermentation and adsorption. Air-dried and chopped rice straw was treated with either fermentation for 30 d after adding 1.5 L nutrient solution(50 m L inocula L–1, 1.2×1012 CFU m L–1 inocula) kg–1 straw dry matter, or spraying a large amount of culture broth(1.5 L kg–1 straw dry matter, 1.5×1011 CFU m L–1 culture broth) on the straw and allowing it to adsorb for 30 min. The feed quality and aerobic stability of the resulting forage were examined. Both treatments improved the feed quality of rice straw, and adsorption was better than fermentation for preserving nutrients and improving digestibility, as evidenced by higher dry matter(DM) and crude protein(CP) concentrations, lower neutral detergent fiber(NDF), acid detergent fiber(ADF) and NH3-N concentrations, as well as higher lactic acid production and in vitro digestibility of DM(IVDMD). The aerobic stability of the adsorbed straw and the fermented straw was 392 and 480 h, respectively. After being exposed to air, chemical components and microbial community of the fermented straw were more stable than the adsorbed straw.展开更多
[ Objective] To screen suitable lactic acid bacterium strains from forage corn which can be used as silage additives. [ Method] The lactic acid bacterium strains were isolated by inoculation on MRS solid medium contai...[ Objective] To screen suitable lactic acid bacterium strains from forage corn which can be used as silage additives. [ Method] The lactic acid bacterium strains were isolated by inoculation on MRS solid medium containing calcium carbonate, and they were preliminarily identified through morphological, physiological and biochemical experiments. The acid production efficiency was determined. Twelve strains having strong acid-pro- duction ability were selected, and their salt tolerance and acid tolerance were detected. The sequences of their 16 S rDNA were also analyzed. [ Result] A total of 44 lactic acid bacterium strains were isolated from the forage com. As evidenced by the physiological and biochemical experi- ments, the twelve strains having strong acid-production ability belonged to Leuconostoc, Lactobacillus and Enterococcus, respectively, and they had strong salt tolerance and acid tolerance. According to the sequences of 16 S rDNA, A4, B9, B11, B12 and B14 were Lactobacillus plantarum; A1, A2., A7, A11 and B8 were Leuconostoc mesenteroides dextran subspecies; and AB and A9 were Enterococcus hirae. [ Conclusion ] The lactic acid bacterium strains with strong acid-production ability isolated from forage corn can be developed into silage additives.展开更多
In dairy and food industries lactic acid bacteria (LAB) have been used in form of starter culture that plays vital role in fermentation; as flavouring and texturizing or as preservative agents. There is increasing e...In dairy and food industries lactic acid bacteria (LAB) have been used in form of starter culture that plays vital role in fermentation; as flavouring and texturizing or as preservative agents. There is increasing evidence that lactobacilli which inhabit the gastrointestinal tract develop antimicrobial activities and participate in the host's defence system[1]. During fermentation, most of the LAB produces a number of different compounds like organic acids, hydrogen peroxide, diacetyl, acetaldehyde, carbon dioxide, polysaccharides, and proteinaceous compounds called bacteriocins or bacteriocinogenic peptides.展开更多
Objective: To study some soybean cultivars commonly used in Northern Thailand that exhibit high nutritional profile and to investigate the changes in bioactive principles and antioxidant capacity of the fermented soy ...Objective: To study some soybean cultivars commonly used in Northern Thailand that exhibit high nutritional profile and to investigate the changes in bioactive principles and antioxidant capacity of the fermented soy broth that was prepared using the selected soybean cultivar and Lactobacillus paracasei HII02 mediated fermentation process.Methods: The best soybean cultivar was subjected to fermentation, and then analyzed the phytochemical, antioxidant and nutritional changes by high performance liquid chromatography and spectrophotometric analysis.Results: Sor Jor 2 soybean cultivar showed rich nutritional profile and was subjected to fermentation process. Lactobacillus paracasei HII02 mediated fermentation of Sor Jor 2 soybean exhibited stable physical and chemical characteristics. Lactic acid bacteria mediated fermentation also increased the aglycone forms of isoflavone content, exhibited antioxidant capacity and thereby enhanced the quality of the fermented soy broth. It also prevented the growth of coliforms in fermented soybean.Conclusions: The study results suggest that fermented soybean is rich in nutrition and considered to be safe for consumption for the improvement of health and to treat the malnutrition.展开更多
Objective: To investigate the antibacterial effect of selected lactic acid bacteria(LAB)biofilms on the planktonic and biofilm population of methicillin-resistant Staphylococcus aureus(MRSA)(S547).Methods: In this stu...Objective: To investigate the antibacterial effect of selected lactic acid bacteria(LAB)biofilms on the planktonic and biofilm population of methicillin-resistant Staphylococcus aureus(MRSA)(S547).Methods: In this study, biofilm-forming LAB were isolated from tairu and kefir. Isolate Y1 and isolate KF were selected based on their prominent inhibition against test pathogens(using spot-on-agar method and agar-well-diffusion assay) and efficient biofilm production(using tissue culture plate method). They were then identified as Lactobacillus casei(L. casei) Y1 and Lactobacillus plantarum(L. plantarum) KF, respectively using16 S r DNA gene sequencing. The influence of incubation time, temperature and aeration on the biofilm production of L. casei Y1 and L. plantarum KF was also investigated using tissue culture plate method. The inhibitory activity of both the selected LAB biofilms was evaluated against MRSA(Institute for Medical Research code: S547) using L. plantarum ATCC 8014 as the reference strain.Results: L. casei Y1 showed the highest reduction of MRSA biofilms, by 3.53 log at48 h while L. plantarum KF records the highest reduction of 2.64 log at 36 h. In inhibiting planktonic population of MRSA(S547), both L. casei Y1 and L. plantarum KF biofilms recorded their maximum reduction of 4.13 log and 3.41 log at 24 h, respectively. Despite their inhibitory effects being time-dependent, both LAB biofilms exhibited good potential in controlling the biofilm and planktonic population of MRSA(S547).Conclusions: The results from this study could highlight the importance of analysing biofilms of LAB to enhance their antibacterial efficacy. Preferably, these protective biofilms of LAB could also be a better alternative to control the formation of biofilms by pathogens such as MRSA.展开更多
Lactic acid bacteria have been important industrial floras in the food fermentation production industry since ancient times.Their metabonomics technology has been widely used in the process monitoring,product classifi...Lactic acid bacteria have been important industrial floras in the food fermentation production industry since ancient times.Their metabonomics technology has been widely used in the process monitoring,product classification and flavor formation mechanism of lactic acid bacteria-fermented foods.In this study,we discussed the application status of metabonomics technology in lactic acid bacteria-fermented food industry and scientific research,including dairy products,soy products,beverages and some pickled foods.Metabolomics will be applied in the research fields of lactic acid bacteria metabolism mechanism of lactic acid bacteria-fermented foods,lactic acid bacteria metabolomics database construction and expansion,metabolomics and genomics,and proteomics.In particular,the metabolomics technology will be introduced into product development and quality monitoring of traditional Chinese lactic acid bacteria-fermented foods,such as fermented bean curd and suancai,thereby perfecting industry norms and improving the level of industry development.展开更多
<span style="font-family:;" "=""><span style="font-family:Verdana;">The uropathogenic </span><i><span style="font-family:Verdana;">Staphylococ...<span style="font-family:;" "=""><span style="font-family:Verdana;">The uropathogenic </span><i><span style="font-family:Verdana;">Staphylococcus</span></i></span><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:Verdana;">saprophyticus</span></i><span style="font-family:;" "=""><span style="font-family:Verdana;"> is reported severally to be resistant to the drugs often used empirically for treatment of urinary tract infections (UTIs). Their ability to exhibit resistance to multiple drugs is a great de</span><span style="font-family:Verdana;">al of threat to successes recorded in the management of UTIs cause</span><span style="font-family:Verdana;">d by this pathogen. Lactic acid bacteria (LAB) have been demonstrated to exhibit an</span><span style="font-family:Verdana;">timicrobial activities but studies about their prospect against multi</span><span style="font-family:Verdana;">-drug resistant </span><i><span style="font-family:Verdana;">S.</span></i> <i><span style="font-family:Verdana;">saprophyticus</span></i><span style="font-family:Verdana;"> are quite few. This study therefore investigated acti</span><span><span style="font-family:Verdana;">vities of LAB against the multi-drug resistant </span><i><span style="font-family:Verdana;">S</span></i><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">saprophyticus</span></i><span style="font-family:Verdana;"> recover</span></span><span style="font-family:Verdana;">ed fro</span><span style="font-family:Verdana;">m urine samples of symptomatic women. The three differ</span><span style="font-family:Verdana;">ent species of LAB </span><span><span style="font-family:Verdana;">(</span><i><span style="font-family:Verdana;">Lactobacillus</span></i></span></span><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:Verdana;">fermentum</span></i><span style="font-family:;" "=""><span style="font-family:Verdana;"> BTA 62, </span><i><span style="font-family:Verdana;">Lactobacillus</span></i></span><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:Verdana;">johnsonii</span></i><span style="font-family:;" "=""><span style="font-family:Verdana;"> BTA 86 and </span><i><span style="font-family:Verdana;">Weis</span></i></span><i><span style="font-family:Verdana;">sella</span></i><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:Verdana;">confusa</span></i><span style="font-family:Verdana;"> BTA 40) previously isolated and identified by 16S rRNA s</span><span style="font-family:;" "=""><span style="font-family:Verdana;">e</span><span style="font-family:Verdana;">quencing were selected based on their history of antimicrobial activities. Their</span><span style="font-family:Verdana;"> m</span><span style="font-family:Verdana;">etabolites were employed in the antagonistic assays against six (6) mu</span><span style="font-family:Verdana;">lti-drug resista</span><span style="font-family:Verdana;">nt test pathogens recovered fro</span><span style="font-family:Verdana;">m urine samples of symptomatic, non-pregnant women attending clinics in Lagos, Nigeria and the control (</span><i><span style="font-family:Verdana;">S</span></i><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">saprophyticus</span></i><span style="font-family:Verdana;"> subs bovis strain DSM 18669) following standard procedures. </span><span style="font-family:Verdana;">The pathogens showed resistances to almost all the antibiotics except</span><span style="font-family:Verdana;"> levofloxaci</span><span style="font-family:Verdana;">n, ciprofloxacin, imipenem while the control showed resistance to thr</span><span style="font-family:Verdana;">ee. The LAB, </span><i><span style="font-family:Verdana;">L.</span></i></span><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:Verdana;">fermentum</span></i><span style="font-family:;" "=""><span style="font-family:Verdana;"> inhibited five (83.3%) of the pathogens with zone diameter of 12 - 17 mm, followed by </span><i><span style="font-family:Verdana;">W</span></i><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">confusa</span></i><span style="font-family:Verdana;"> inhibiting three (50%) with 15 - 17 mm. </span><i><span style="font-family:Verdana;">Lactobacillus</span></i></span><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:Verdana;">johnsonii</span></i><span style="font-family:;" "=""><span style="font-family:Verdana;"> on the other hand, inhibited a pathogen and the control with zones of 13 mm and 14 mm respectively. In conclusion, the extracted metabolites of LAB inhibited the growth of multi-drug resistant clinical isolates of uropathogenic </span><i><span style="font-family:Verdana;">S</span></i><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">saprophyticus</span></i><span style="font-family:Verdana;"> and may therefore be potent alternatives to antibiotics.</span></span>展开更多
<span style="line-height:1.5;"><span style="font-family:Verdana;">An antioxidant is a substance that inhibits the oxidation of other molecules caused by free radicals. The inbuilt antio...<span style="line-height:1.5;"><span style="font-family:Verdana;">An antioxidant is a substance that inhibits the oxidation of other molecules caused by free radicals. The inbuilt antioxidant systems possessed by living or</span><span style="font-family:Verdana;">g</span><span style="font-family:Verdana;">anisms are generally not enough to prevent them from oxidati</span><span style="font-family:Verdana;">ve damage</span><span style="font-family:Verdana;">s and the use</span></span><span style="line-height:1.5;font-family:Verdana;">s</span><span style="line-height:1.5;font-family:Verdana;"> of synthetic antioxidants also ha</span><span style="line-height:1.5;font-family:Verdana;">ve</span><span style="line-height:1.5;font-family:Verdana;"> some harmful effects. T</span><span style="line-height:1.5;"><span style="font-family:Verdana;">his study was aimed at evaluating the antioxidant activities of exopolysaccharides p</span><span style="font-family:Verdana;">roduced by lactic acid bacteria isolated from yoghurt. Lactic acid bac</span><span style="font-family:Verdana;">teria (LAB) were isolated from six different brands of commercially available yoghurt using deMan Rogosa Sharpe (MRS) agar. The LAB isolates were identified based on morphological and biochemical analyses and were screened for exopolysaccharide (EPS) production. The LAB isolates screened positive were used for EPS production in a liquid medium and the EPS produced were purified and quantified using standard methods. Antioxidant activities of the E</span><span style="font-family:Verdana;">PS were evaluated by determining the 1,1-dip</span><span style="font-family:Verdana;">henyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, ferric ion reducing power, and total phenolic contents. Data obtained were analysed using Analysis of Variance. Total lactic acid bacterial count obtained from the yoghurt samples ranged from 0 - 3.9 × 10</span><sup><span style="font-family:Verdana;">4</span></sup><span style="font-family:Verdana;"> CFU/mL with sample A (Fan Yoghurt) having the highest LAB count (3.9 × 10</span><sup><span style="font-family:Verdana;">4</span></sup><span style="font-family:Verdana;"> CFU/mL). The isolated LAB and their incidence rate were </span><i><span style="font-family:Verdana;">Lactobacillus plantarum </span></i><span style="font-family:Verdana;">(25.49%),</span><i><span style="font-family:Verdana;"> L. delbrueckii </span></i><span style="font-family:Verdana;">(19.61%),</span><i><span style="font-family:Verdana;"> L. fermentum </span></i><span style="font-family:Verdana;">(15.69%),</span><i><span style="font-family:Verdana;"> L. acidophilus </span></i><span style="font-family:Verdana;">(13.73%), </span><i><span style="font-family:Verdana;">Leuconostoc mesenteroides </span></i><span style="font-family:Verdana;">(11.76%),</span><i><span style="font-family:Verdana;"> Lactococcus lactis </span></i><span style="font-family:Verdana;">(7.84%), and </span><i><span style="font-family:Verdana;">Lactobacillus casei </span></i><span style="font-family:Verdana;">(5.88%). Fifty-one out of the 64 LAB isolates were screened positive for EPS production and only six were able to produce substantial quantity of EPS ranging from 127.4 - 208.5 mg/L. The exopolysaccharides produced by </span><i><span style="font-family:Verdana;">L. fermentum</span></i><span style="font-family:Verdana;"> had the highest DPPH radical scavenging activity (62.90%) while that of </span><i><span style="font-family:Verdana;">L. plantarum</span></i><span style="font-family:Verdana;"> had the lowest (23.10%) at a concentration of 1000 μg/mL. Also, the EPS produced by </span><i><span style="font-family:Verdana;">L. fermentum</span></i><span style="font-family:Verdana;"> recorded the highest ferric ion reducing power (12.89 mg AAE/mL) at 1000 μg/mL while that of </span><i><span style="font-family:Verdana;">L. plantarum</span></i><span style="font-family:Verdana;"> had the lowest (5.62 mg AAE/mL). At 1000 μg/mL, the total phenolic contents of the EPS samples ranged from 1.41 - 1.58 mg GAE/mL, and the EPS produced by </span><i><span style="font-family:Verdana;">L. fermentum </span></i><span style="font-family:Verdana;">had the highest (1.58 mg GAE/mL) while those produced by </span><i><span style="font-family:Verdana;">L. paracasei </span></i><span style="font-family:Verdana;">had the lowest (1.41 mg GAE/mL). This study revealed that the exopolysaccharides produced by the LAB isolates showed high antioxidant activities with respect to their DPPH free radical scavenging activity, ferric ion reducing power and total phenolic contents.展开更多
The objective of this study was to isolate lactic acid bacteria(LAB) strains from different origins and to select the best strains for ensiling Robinia pseudoacacia(RB) and Morus alba L.(MB)leaves. The LAB strai...The objective of this study was to isolate lactic acid bacteria(LAB) strains from different origins and to select the best strains for ensiling Robinia pseudoacacia(RB) and Morus alba L.(MB)leaves. The LAB strains were inoculated into the extracted liquid obtained from RB and MB leaves to evaluate the fermentation products. 11 LAB strains were selected for further experiments based on the highest products of lactic or acetic acid, including 1 strain of Weissella confusa, 2 of Lactobacillus reuteri and 8 of Lactobacillus plantarum.The API 50 CH fermentation experiment indicated that all of the selected 11 LAB strains utilised most of the carbohydrates. All the strains grew at temperatures between 10 and 45℃ and at a p H of 3.5 to 4.5; however, L. reuteri F7 and F8 tolerated a p H as low as 3.0. All 11 LAB strains showed antibacterial activity against Listeria monocytogens, Escherichia coil, Salmonella sp. and Acetobacter pasteurianus; however, after excluding the effect of organic acids, only F7 and F8 still exhibited antibacterial activity. The present study indicated that the selected 11 LAB strains could be used to prepare silages of RB and MB leaves, especially L. reuteri F7 and F8.展开更多
[Objective] The aim of this study was to isolate and identify lactic acid bacteria (LAB) from wheat haulm and to select efficient strains for silage fermentation. [ Method] From 78 LAB strains isolated on the MRS so...[Objective] The aim of this study was to isolate and identify lactic acid bacteria (LAB) from wheat haulm and to select efficient strains for silage fermentation. [ Method] From 78 LAB strains isolated on the MRS solid medium containing calcium carbonate, we selected 43 strains having better acid-production ability through morphological observation, Gram staining, physiological and biochemical tests, acid production test, acid tolerance test and salt tolerance test. These strains were finally identified by sequencing 16 S rDNA. [ Result] Of the 43 LAB strains having better acid-production ability, 37 belonged to Lactobacillus paracasei subsp., one belonged to Lactobacillus rhamnosus and five belonged to Enterococcus faecium, as shown by the sequences of 16 S rDNA. [ Conclusion ] A total of 43 LAB strains having better acid-production ability were selected, which may be developed as high-quality silage additives.展开更多
[Objective] To provide a reference for scientific and rational utilization of forage silage. [Method] The number and species of microorganisms in forage were analyzed, and the characteristics of 11 strains of lactic a...[Objective] To provide a reference for scientific and rational utilization of forage silage. [Method] The number and species of microorganisms in forage were analyzed, and the characteristics of 11 strains of lactic acid bacteria (LAB) were studied. [ Result] All the isolates were Gram-positive, catalase negative and aeroanaerobic. The isolated strains of homofermentation accounted for 78%. The isolates were divided into three groups, Lactobacillus, Leuconostocaceae and Lactococcus, according to their morphological and biochemical characters. [ Conclusion] The microorganisms in forage in northwest China were isolated and identified, which provides a scientific basis for utilization of forage silage.展开更多
Background: Gastric ulcer is one of the most common gastrointestinal diseases with a worldwide prevalence of about 40% in the developed countries and 80% in Africa. Acid inhibitors, anticholinergics, histamine H2-anta...Background: Gastric ulcer is one of the most common gastrointestinal diseases with a worldwide prevalence of about 40% in the developed countries and 80% in Africa. Acid inhibitors, anticholinergics, histamine H2-antagonists and antibiotics are commonly used to treat gastric ulcer. However, the accumulating evidence for resistance to antibiotics and the side effects of antibiotics and acid inhibitors, anticholinergics and histamine H2-antagonists. Therefore, there is an urgent need for approaches to treat and prevent gastric ulcer. One alternative strategy is the use of probiotic lactic acid bacteria. Aim of the study: This study aimed to isolate and characterised probiotic lactic acid bacteria from palm wine and fermented milk, and to evaluate their antiulcerogenic potentials on ethanol-induced gastric ulcer in mice. Methods: Probiotic lactic acid bacteria were isolated from the fermented milk and palm wine using pour plate technique on MRS agar and identified using the 16S r RNA gene sequencing. For functional properties and selection, acid and bile salt tolerance were evaluated based on viable colony count on MRS agar. Two probiotic lactic acid bacteria were selected for in vivo studies. Fifty-four healthy young adult Balb/c mice were randomly divided into 9 groups of 6 mice each. Gastric ulcer was induced in mice using one oral dose of absolute ethanol (10 mL/kg body weight). The probiotic lactic acid bacteria (F1 and F2) at different doses (MF3 = 9 × 10<sup>8</sup> CFU/mL, MF6 = 1.8 × 10<sup>9</sup> CFU/mL and MF9 = 2.7 × 10<sup>9</sup> CFU/mL) and omeprazole (20 mg/kg) (a reference drug) were orally administrated daily for 14 days before ulcer induction. These mice were sacrificed 1hour after induction and the stomach contents were collected for volume and pH determination. The stomachs were subjected to macroscopic, biochemical and histopathological analysis. Results: Among the isolates obtained, two were considered to have the best acid and bile tolerance capacity (viable count > 7.5 logCFU/ml) and were identified as Limosilactobacillus fermentum strain BB101 (F1) and Lactobacillus casei strain 02 (F2). Oral administration of probiotics Lactic acid bacteria F1 and F2 significantly attenuated gastric ulcer as revealed by significant reduction (P Conclusion: The results of this study revealed that palm wine and fermented milk are sources of potential probiotic lactic acid bacteria, that is lactobacillus fermentum strain BB101 and Lactobacillus casei 02 with excellent bile and acid tolerance capacity. Also, these probiotic lactic acid bacteria exhibit gastroprotective effect on ethanol-induced gastric ulcer via antioxidant, enhance gastric ulcer healing, antacids, and anti-secretary effects.展开更多
基金supported by the National Key Research and Development Program of China(2021YFD2100902-3)the National Natural Science Foundation of China(32072258)+5 种基金Major Science and Technology Program of Heilongjiang(2020ZX08B02)Harbin University of Commerce“Young Innovative Talents”Support Program(2019CX062020CX262020CX27)the Central Financial Support for the Development of Local Colleges and Universities,Graduate Innovation Research Project of Harbin University of Commerce(YJSCX2021-698HSD)Training plan of Young Innovative Talents in Universities of Heilongjiang(UNPYSCT-2020218).
文摘The effects of 5 lactic acid bacteria(LAB)fermentation on the pasting properties of glutinous rice flour were compared,and suitable fermentation strains were selected based on the changes of viscosity,setback value,and breakdown value to prepare LAB compound starter cultures.The results revealed that Latilactobacillus sakei HSD004 and Lacticaseibacillus rhamnosus HSD005 had apparent advantages in increasing the viscosity and reducing the setback and breakdown values of glutinous rice flour.In particular,the compound starter created using the two abovementioned LAB in the ratio of 3:1 had better performance than that using a single LAB in improving the pasting properties and increasing the water and oil absorption capacity of glutinous rice flour.Moreover,the gelatinization enthalpy of the fermented samples increased significantly.For frozen glutinous rice dough stored for 28 days,the viscoelasticity of frozen dough prepared by compound starter was better than that of control dough,and the freezable water content was lower than that of control dough.These results indicate that compound LAB fermentation is a promising technology in the glutinous rice-based food processing industry,which has significance for its application.
基金supported by the National Natural Science Foundation of China(32102605)the Agricultural Science and Technology Innovation Program under Grant(CAAS-ASTIP-2020-IAR)。
文摘Food allergy as a global health problem threatens food industry.Bee pollen(BP)is a typical food with allergenic potentials,although it performs various nutritional/pharmacological functions to humans.In this study,lactic acid bacteria(LAB)were used to ferment Brassica napus BP for alleviating its allergenicity.Four novel allergens(glutaredoxin,oleosin-B2,catalase and lipase)were identified with significant decreases in LAB-fermented BP(FBP)than natural BP by proteomics.Meanwhile,metabolomics analysis showed significant increases of 28 characteristic oligopeptides and amino acids in FBP versus BP,indicating the degradation of LAB on allergens.Moreover,FBP showed alleviatory effects in BALB/c mice,which relieved pathological symptoms and lowered production of allergic mediators.Microbial high-throughput sequencing analysis showed that FBP could regulate gut microbiota and metabolism to strengthen immunity,which were closely correlated with the alleviation of allergic reactivity.These findings could contribute to the development and utilization of hypoallergenic BP products.
基金supported by Jiangsu Agriculture Science and Technology Innovatioin Fund(CX(21)2003)。
文摘In this study,a new type of 3 D printed living biological hydrogel was developed by integrating lactic acid bacteria(LAB)into biocompatible and non-toxic polymer materials.Interestingly,the living materials loaded with LAB can be freeze-dried and reused for more than 100 times.The bio-hydrogel can be used to co-culture different LAB and keep its fermentation performance stable in long-term use.The release kinetics model and response surface method were used to simulate and optimize the bacteria release mode in the bio-hydrogel.The results show that the release of bacteria from hydrogel is regulated by the coupling of Fickian diffusion and polymer swelling.The stability of LAB hydrogel was evaluated by reuse experiments.The images of confocal microscopy and scanning electron microscope showed that the bacteria with high cell viability were distributed in the hydrogel and intact structure of the living hydrogel was maintained after 100 times of reuse as yoghurt starter.In conclusion,the 3 D printed LAB bio-hydrogel developed in this study has the advantage of reuse and sustainability,which is expected to open up a new way for the preparation of food culture starter.
基金supported by the project of Jiangsu Independent Innovation,China(CX(15)1003-3)the Key Technologies R&D Program of China during the 13th Five-Year Plan period(2016YFC0502005)the Special Project of Grass of Tibet Autonomous Region for the 13th Five-Year Plan,China
文摘This study was conducted to evaluate the effect of lactic acid bacteria and propionic acid on the fermentation quality, aer- obic stability and in vitro gas production kinetics and digestibility of whole-crop corn based totalmixed ration (TMR) silage. Total mixed ration was ensiled with four treatments: (1) no additives (control); (2) an inoculant (Lactobacillus plantarum) (L); (3) propionicacid (P); (4) propionic acid+lactic acid bacteria (PL). All treatments were ensiled in laboratory-scale silos for 45 days, and then subjected to an aerobic stability test for12 days. Further, four TMR silages were incubated in vitro with buffered rumen fluid to study in vitro gas production kinetics and digestibility. The results indicated that all TMR silages had good fermentation characteristics with low pH (〈3.80) and ammonia nitrogen (NH3-N) contents, and high lactic acid contents as well as Flieg points. Addition of L further improved TMR silage quality with more lactic acid production. Addition of P and PL decreased lactic acid and NH3-N contents of TMR silage compared to the control (P〈0.05). After 12 days aerobic exposure, P and PL silages remained stable, but L and the control silages deteriorated as indicated by a reduction in lactic acid and an increase in pH, and numbers of yeast. Compared to the control, addition of L had no effects on TMR silage in terms of 72 h cumulative gas production, in vitro dry matter digestibility, metabolizable energy, net energy for lactation and short chain fatty acids, whereas addition of PL significantly (P〈0.05) increased them. L silage had higher (P〈0.05) in vitro neutral detergent fiber digestibility than the control silage. The results of our study suggested that TMR silage prepared with whole-crop corn can be well preserved with or without additives. Furthermore, the findings of this study suggested that propionic acid is compatible with lactic acid bacteria inoculants, and when used together, although they reduced lactic acid production of TMR silage, they improved aerobic stability and in vitro nutrients digestibility of TMR silage.
基金supported by the National Key R&D Program of China (2017YFD0502102)the National Technology Leader “Ten Thousand People Plan” of China (201502510410040)the National Key Technology R&D Program of China during the 12th Five-year Plan period of China (2011BAD17B02)
文摘This study assessed the effects of lactic acid bacteria(LAB), cellulase, cellulase-producing Bacillus pumilus and their combinations on the fermentation characteristics, chemical composition, bacterial community and in vitro digestibility of alfalfa silage. A completely randomized design involving a 8(silage additives)×3 or 2(silage days) factorial arrangement of treatments was adopted in the present study. The 8 silage additive treatments were: untreated alfalfa(control); two commercial additives(GFJ and Chikuso-1); an originally selected LAB(Lactobacillus plantarum a214) isolated from alfalfa silage; a cellulase-producing Bacillus(CB) isolated from fresh alfalfa; cellulase(C); and the combined additives(a214+C and a214+CB). Silage fermentation characteristics, chemical composition and microorganism populations were analysed after 30, 60 and 65 days(60 days followed by exposure to air for five additional days). In vitro digestibility was analysed for 30 and 60 days. Compared with the other treatments, selected LAB a214, a214 combined with either C or CB, and Chikuso-1 had the decreased(P<0.001) pH and increased(P<0.001) lactic acid concentrations during the ensiling process, and there were no differences(P>0.05) among them. Fiber degradation was not significant(P≥0.054) in any C or CB treatments. The a214 treatment showed the highest(P=0.009) in vitro digestibility of dry matter(595.0 g kg–1DM) after ensiling and the highest abundance of Lactobacillus(69.42 and 79.81%, respectively) on days 60 and 65, compared to all of other treatments. Overall, the silage quality of alfalfa was improved with the addition of a214, which indicates its potential as an alfalfa silage inoculant.
基金supported by the National Natural Science Foundation of China(31502015,31672488)the Natural Science Foundation of Shanxi Province of China(2015021162)
文摘The objective of this study was to investigate the effect of lactic acid bacteria(LAB) inoculums on fermentation quality and in vitro digestibility of corn stover silage.Corn stover was ensiled without(control) or with Lactobacillus plantarum(LP),Enterococcus faecalis(EF),and Enterococcus mundtii(EM) for 45 days.The fermentation characteristics were assessed,and subsequent in vitro dry matter digestibility(DM-D),neutral detergent fiber digestibility(NDF-D),volatile fatty acids(VFA),methane(CH4) production,cellulolytic bacteria proportions and their activities per corn stover silage were also determined.There was no significant difference(P>0.05) among the silage pH,lactic acid,crude protein(CP),water soluble carbohydrates(WSC) and lignocelluloses contents of different treatments.The relative proportions of Ruminococcus flavefaciens and Fibrobacter succinogenes,carboxymethyl-ocellulose and β-glycosidase activities,DM-D,NDF-D,and VFA production of in vitro incubation was higher(P<0.05) for silages inoculated with LP and EF than those of the control silage.Silage inoculated with LP showed the lowest(P<0.05) CH4 production per unit yield of VFA,which was positively corresponded to the lowest(P<0.05) ratio of acetate to propionate.In summary,the ensiling fermentation quality and subsequent utilization of corn stover silage were efficiently improved by inoculated with L.plantarum.
基金Supported by 863 Projects (2008AA10Z311)National Science and Technology Support Projects (2009BADB9B06)+1 种基金Started Post-doctoral Research Grant of Heilongjiang Province (LBH-Q07023)Harbin Technological Innovation of Special Funds (2007RFQXN020)
文摘According to the sequence of the bile salt hydrolase (BSH) gene of Bifidobacterium and the restriction enzyme cutting sites of expression vector pNZ8148, primers were designed and the bile salt hydrolase (BSH) gene was gotten from Bacillus bifidus ATCC 29521 by PCR. BSH gene was inserted into lactic acid bacteria expression vector pNZ8148 to construct the recombinant pNZ8148-BSH. The recombinant pNZ8148-BSH was transferred into lactic acid bacteria NZ9000 with electrotransformation method. And the recombinant which could express BSH protein was obtained. It was identified by SDS-PAGE electrophoresis and activity verification. The result could provide a rationale reference for expressing BSH in lactic acid bacteria.
基金supported by Sathyabama Institute of Science and Technology,Chennai,Tamil Nadu,India and Indian Council of Medical Research(ICMR),New Delhi,India(Ref.No:5/8/5/19/2014-ECD-I)
文摘Tuberculosis(TB) is a communicable disease caused by Mycobacterium tuberculosis(M. tuberculosis). WHO estimated that 10.4 million new(incident) TB cases worldwide in year 2016. The increased prevalence of drug resistant strains and side effects associated with the current anti-tubercular drugs make the treatment options more complicated. Hence, there are necessities to identify new drug candidates to fight against various sub-populations of M. tuberculosis with less or no toxicity/side effects and shorter treatment duration. Bacteriocins produced by lactic acid bacteria(LAB) attract attention of researchers because of its "Generally recognized as safe" status. LAB and its bacteriocins possess an effective antimicrobial activity against various bacteria and fungi. Interestingly bacteriocins such as nisin and lacticin 3147 have shown antimycobacterial activity in vitro. As probiotics, LAB plays a vital role in promoting various health benefits including ability to modulate immune response against various infectious diseases. LAB and its metabolic products activate immune system and thereby limiting the M. tuberculosis pathogenesis. The protein and peptide engineering techniques paved the ways to obtain hybrid bacteriocin derivatives from the known peptide sequence of existing bacteriocin. In this review, we focus on the antimycobacterial property and immunomodulatory role of LAB and its metabolic products. Techniques for large scale synthesis of potential bacteriocin with multifunctional activity and enhanced stability are also discussed.
基金supported by the National Key Technology Research and Development Program of China during the 12th Five-Year Plan period (2012BAD14B01)the Special Fund for Agro-Scientific Research in the Public Interest, China (201303080)
文摘To improve the nutritional value and the palatability of air-dried rice straw, culture broth of the lactic acid bacteria community SFC-2 was used to examine the effects of two different treatments, fermentation and adsorption. Air-dried and chopped rice straw was treated with either fermentation for 30 d after adding 1.5 L nutrient solution(50 m L inocula L–1, 1.2×1012 CFU m L–1 inocula) kg–1 straw dry matter, or spraying a large amount of culture broth(1.5 L kg–1 straw dry matter, 1.5×1011 CFU m L–1 culture broth) on the straw and allowing it to adsorb for 30 min. The feed quality and aerobic stability of the resulting forage were examined. Both treatments improved the feed quality of rice straw, and adsorption was better than fermentation for preserving nutrients and improving digestibility, as evidenced by higher dry matter(DM) and crude protein(CP) concentrations, lower neutral detergent fiber(NDF), acid detergent fiber(ADF) and NH3-N concentrations, as well as higher lactic acid production and in vitro digestibility of DM(IVDMD). The aerobic stability of the adsorbed straw and the fermented straw was 392 and 480 h, respectively. After being exposed to air, chemical components and microbial community of the fermented straw were more stable than the adsorbed straw.
基金supported by the funds from the National Natural Science Foundation of China (30760008)
文摘[ Objective] To screen suitable lactic acid bacterium strains from forage corn which can be used as silage additives. [ Method] The lactic acid bacterium strains were isolated by inoculation on MRS solid medium containing calcium carbonate, and they were preliminarily identified through morphological, physiological and biochemical experiments. The acid production efficiency was determined. Twelve strains having strong acid-pro- duction ability were selected, and their salt tolerance and acid tolerance were detected. The sequences of their 16 S rDNA were also analyzed. [ Result] A total of 44 lactic acid bacterium strains were isolated from the forage com. As evidenced by the physiological and biochemical experi- ments, the twelve strains having strong acid-production ability belonged to Leuconostoc, Lactobacillus and Enterococcus, respectively, and they had strong salt tolerance and acid tolerance. According to the sequences of 16 S rDNA, A4, B9, B11, B12 and B14 were Lactobacillus plantarum; A1, A2., A7, A11 and B8 were Leuconostoc mesenteroides dextran subspecies; and AB and A9 were Enterococcus hirae. [ Conclusion ] The lactic acid bacterium strains with strong acid-production ability isolated from forage corn can be developed into silage additives.
文摘In dairy and food industries lactic acid bacteria (LAB) have been used in form of starter culture that plays vital role in fermentation; as flavouring and texturizing or as preservative agents. There is increasing evidence that lactobacilli which inhabit the gastrointestinal tract develop antimicrobial activities and participate in the host's defence system[1]. During fermentation, most of the LAB produces a number of different compounds like organic acids, hydrogen peroxide, diacetyl, acetaldehyde, carbon dioxide, polysaccharides, and proteinaceous compounds called bacteriocins or bacteriocinogenic peptides.
基金Chiang Mai University provided the financial supports for Innovation Center for Holistic Health,Nutraceuticals,and Cosmeceuticals(CMUgrant sanction,Dated:1 October 2016)
文摘Objective: To study some soybean cultivars commonly used in Northern Thailand that exhibit high nutritional profile and to investigate the changes in bioactive principles and antioxidant capacity of the fermented soy broth that was prepared using the selected soybean cultivar and Lactobacillus paracasei HII02 mediated fermentation process.Methods: The best soybean cultivar was subjected to fermentation, and then analyzed the phytochemical, antioxidant and nutritional changes by high performance liquid chromatography and spectrophotometric analysis.Results: Sor Jor 2 soybean cultivar showed rich nutritional profile and was subjected to fermentation process. Lactobacillus paracasei HII02 mediated fermentation of Sor Jor 2 soybean exhibited stable physical and chemical characteristics. Lactic acid bacteria mediated fermentation also increased the aglycone forms of isoflavone content, exhibited antioxidant capacity and thereby enhanced the quality of the fermented soy broth. It also prevented the growth of coliforms in fermented soybean.Conclusions: The study results suggest that fermented soybean is rich in nutrition and considered to be safe for consumption for the improvement of health and to treat the malnutrition.
基金Funding for this project was provided by Fundamental Research Grant Scheme(FRGS)of the Ministry of Higher Education,Malaysia(zuhainis@upm.edu.my)(Grant number:5524488)
文摘Objective: To investigate the antibacterial effect of selected lactic acid bacteria(LAB)biofilms on the planktonic and biofilm population of methicillin-resistant Staphylococcus aureus(MRSA)(S547).Methods: In this study, biofilm-forming LAB were isolated from tairu and kefir. Isolate Y1 and isolate KF were selected based on their prominent inhibition against test pathogens(using spot-on-agar method and agar-well-diffusion assay) and efficient biofilm production(using tissue culture plate method). They were then identified as Lactobacillus casei(L. casei) Y1 and Lactobacillus plantarum(L. plantarum) KF, respectively using16 S r DNA gene sequencing. The influence of incubation time, temperature and aeration on the biofilm production of L. casei Y1 and L. plantarum KF was also investigated using tissue culture plate method. The inhibitory activity of both the selected LAB biofilms was evaluated against MRSA(Institute for Medical Research code: S547) using L. plantarum ATCC 8014 as the reference strain.Results: L. casei Y1 showed the highest reduction of MRSA biofilms, by 3.53 log at48 h while L. plantarum KF records the highest reduction of 2.64 log at 36 h. In inhibiting planktonic population of MRSA(S547), both L. casei Y1 and L. plantarum KF biofilms recorded their maximum reduction of 4.13 log and 3.41 log at 24 h, respectively. Despite their inhibitory effects being time-dependent, both LAB biofilms exhibited good potential in controlling the biofilm and planktonic population of MRSA(S547).Conclusions: The results from this study could highlight the importance of analysing biofilms of LAB to enhance their antibacterial efficacy. Preferably, these protective biofilms of LAB could also be a better alternative to control the formation of biofilms by pathogens such as MRSA.
基金Yantai Science and Technology Planing Project(2019ZDCX013)High-efficiency Ecological Agriculture Innovation Project of Taishan Industry Leading Talent Engineering(LJNY202001)Key R&D Program of Shandong Province(2019GNC106019).
文摘Lactic acid bacteria have been important industrial floras in the food fermentation production industry since ancient times.Their metabonomics technology has been widely used in the process monitoring,product classification and flavor formation mechanism of lactic acid bacteria-fermented foods.In this study,we discussed the application status of metabonomics technology in lactic acid bacteria-fermented food industry and scientific research,including dairy products,soy products,beverages and some pickled foods.Metabolomics will be applied in the research fields of lactic acid bacteria metabolism mechanism of lactic acid bacteria-fermented foods,lactic acid bacteria metabolomics database construction and expansion,metabolomics and genomics,and proteomics.In particular,the metabolomics technology will be introduced into product development and quality monitoring of traditional Chinese lactic acid bacteria-fermented foods,such as fermented bean curd and suancai,thereby perfecting industry norms and improving the level of industry development.
文摘<span style="font-family:;" "=""><span style="font-family:Verdana;">The uropathogenic </span><i><span style="font-family:Verdana;">Staphylococcus</span></i></span><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:Verdana;">saprophyticus</span></i><span style="font-family:;" "=""><span style="font-family:Verdana;"> is reported severally to be resistant to the drugs often used empirically for treatment of urinary tract infections (UTIs). Their ability to exhibit resistance to multiple drugs is a great de</span><span style="font-family:Verdana;">al of threat to successes recorded in the management of UTIs cause</span><span style="font-family:Verdana;">d by this pathogen. Lactic acid bacteria (LAB) have been demonstrated to exhibit an</span><span style="font-family:Verdana;">timicrobial activities but studies about their prospect against multi</span><span style="font-family:Verdana;">-drug resistant </span><i><span style="font-family:Verdana;">S.</span></i> <i><span style="font-family:Verdana;">saprophyticus</span></i><span style="font-family:Verdana;"> are quite few. This study therefore investigated acti</span><span><span style="font-family:Verdana;">vities of LAB against the multi-drug resistant </span><i><span style="font-family:Verdana;">S</span></i><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">saprophyticus</span></i><span style="font-family:Verdana;"> recover</span></span><span style="font-family:Verdana;">ed fro</span><span style="font-family:Verdana;">m urine samples of symptomatic women. The three differ</span><span style="font-family:Verdana;">ent species of LAB </span><span><span style="font-family:Verdana;">(</span><i><span style="font-family:Verdana;">Lactobacillus</span></i></span></span><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:Verdana;">fermentum</span></i><span style="font-family:;" "=""><span style="font-family:Verdana;"> BTA 62, </span><i><span style="font-family:Verdana;">Lactobacillus</span></i></span><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:Verdana;">johnsonii</span></i><span style="font-family:;" "=""><span style="font-family:Verdana;"> BTA 86 and </span><i><span style="font-family:Verdana;">Weis</span></i></span><i><span style="font-family:Verdana;">sella</span></i><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:Verdana;">confusa</span></i><span style="font-family:Verdana;"> BTA 40) previously isolated and identified by 16S rRNA s</span><span style="font-family:;" "=""><span style="font-family:Verdana;">e</span><span style="font-family:Verdana;">quencing were selected based on their history of antimicrobial activities. Their</span><span style="font-family:Verdana;"> m</span><span style="font-family:Verdana;">etabolites were employed in the antagonistic assays against six (6) mu</span><span style="font-family:Verdana;">lti-drug resista</span><span style="font-family:Verdana;">nt test pathogens recovered fro</span><span style="font-family:Verdana;">m urine samples of symptomatic, non-pregnant women attending clinics in Lagos, Nigeria and the control (</span><i><span style="font-family:Verdana;">S</span></i><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">saprophyticus</span></i><span style="font-family:Verdana;"> subs bovis strain DSM 18669) following standard procedures. </span><span style="font-family:Verdana;">The pathogens showed resistances to almost all the antibiotics except</span><span style="font-family:Verdana;"> levofloxaci</span><span style="font-family:Verdana;">n, ciprofloxacin, imipenem while the control showed resistance to thr</span><span style="font-family:Verdana;">ee. The LAB, </span><i><span style="font-family:Verdana;">L.</span></i></span><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:Verdana;">fermentum</span></i><span style="font-family:;" "=""><span style="font-family:Verdana;"> inhibited five (83.3%) of the pathogens with zone diameter of 12 - 17 mm, followed by </span><i><span style="font-family:Verdana;">W</span></i><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">confusa</span></i><span style="font-family:Verdana;"> inhibiting three (50%) with 15 - 17 mm. </span><i><span style="font-family:Verdana;">Lactobacillus</span></i></span><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:Verdana;">johnsonii</span></i><span style="font-family:;" "=""><span style="font-family:Verdana;"> on the other hand, inhibited a pathogen and the control with zones of 13 mm and 14 mm respectively. In conclusion, the extracted metabolites of LAB inhibited the growth of multi-drug resistant clinical isolates of uropathogenic </span><i><span style="font-family:Verdana;">S</span></i><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">saprophyticus</span></i><span style="font-family:Verdana;"> and may therefore be potent alternatives to antibiotics.</span></span>
文摘<span style="line-height:1.5;"><span style="font-family:Verdana;">An antioxidant is a substance that inhibits the oxidation of other molecules caused by free radicals. The inbuilt antioxidant systems possessed by living or</span><span style="font-family:Verdana;">g</span><span style="font-family:Verdana;">anisms are generally not enough to prevent them from oxidati</span><span style="font-family:Verdana;">ve damage</span><span style="font-family:Verdana;">s and the use</span></span><span style="line-height:1.5;font-family:Verdana;">s</span><span style="line-height:1.5;font-family:Verdana;"> of synthetic antioxidants also ha</span><span style="line-height:1.5;font-family:Verdana;">ve</span><span style="line-height:1.5;font-family:Verdana;"> some harmful effects. T</span><span style="line-height:1.5;"><span style="font-family:Verdana;">his study was aimed at evaluating the antioxidant activities of exopolysaccharides p</span><span style="font-family:Verdana;">roduced by lactic acid bacteria isolated from yoghurt. Lactic acid bac</span><span style="font-family:Verdana;">teria (LAB) were isolated from six different brands of commercially available yoghurt using deMan Rogosa Sharpe (MRS) agar. The LAB isolates were identified based on morphological and biochemical analyses and were screened for exopolysaccharide (EPS) production. The LAB isolates screened positive were used for EPS production in a liquid medium and the EPS produced were purified and quantified using standard methods. Antioxidant activities of the E</span><span style="font-family:Verdana;">PS were evaluated by determining the 1,1-dip</span><span style="font-family:Verdana;">henyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, ferric ion reducing power, and total phenolic contents. Data obtained were analysed using Analysis of Variance. Total lactic acid bacterial count obtained from the yoghurt samples ranged from 0 - 3.9 × 10</span><sup><span style="font-family:Verdana;">4</span></sup><span style="font-family:Verdana;"> CFU/mL with sample A (Fan Yoghurt) having the highest LAB count (3.9 × 10</span><sup><span style="font-family:Verdana;">4</span></sup><span style="font-family:Verdana;"> CFU/mL). The isolated LAB and their incidence rate were </span><i><span style="font-family:Verdana;">Lactobacillus plantarum </span></i><span style="font-family:Verdana;">(25.49%),</span><i><span style="font-family:Verdana;"> L. delbrueckii </span></i><span style="font-family:Verdana;">(19.61%),</span><i><span style="font-family:Verdana;"> L. fermentum </span></i><span style="font-family:Verdana;">(15.69%),</span><i><span style="font-family:Verdana;"> L. acidophilus </span></i><span style="font-family:Verdana;">(13.73%), </span><i><span style="font-family:Verdana;">Leuconostoc mesenteroides </span></i><span style="font-family:Verdana;">(11.76%),</span><i><span style="font-family:Verdana;"> Lactococcus lactis </span></i><span style="font-family:Verdana;">(7.84%), and </span><i><span style="font-family:Verdana;">Lactobacillus casei </span></i><span style="font-family:Verdana;">(5.88%). Fifty-one out of the 64 LAB isolates were screened positive for EPS production and only six were able to produce substantial quantity of EPS ranging from 127.4 - 208.5 mg/L. The exopolysaccharides produced by </span><i><span style="font-family:Verdana;">L. fermentum</span></i><span style="font-family:Verdana;"> had the highest DPPH radical scavenging activity (62.90%) while that of </span><i><span style="font-family:Verdana;">L. plantarum</span></i><span style="font-family:Verdana;"> had the lowest (23.10%) at a concentration of 1000 μg/mL. Also, the EPS produced by </span><i><span style="font-family:Verdana;">L. fermentum</span></i><span style="font-family:Verdana;"> recorded the highest ferric ion reducing power (12.89 mg AAE/mL) at 1000 μg/mL while that of </span><i><span style="font-family:Verdana;">L. plantarum</span></i><span style="font-family:Verdana;"> had the lowest (5.62 mg AAE/mL). At 1000 μg/mL, the total phenolic contents of the EPS samples ranged from 1.41 - 1.58 mg GAE/mL, and the EPS produced by </span><i><span style="font-family:Verdana;">L. fermentum </span></i><span style="font-family:Verdana;">had the highest (1.58 mg GAE/mL) while those produced by </span><i><span style="font-family:Verdana;">L. paracasei </span></i><span style="font-family:Verdana;">had the lowest (1.41 mg GAE/mL). This study revealed that the exopolysaccharides produced by the LAB isolates showed high antioxidant activities with respect to their DPPH free radical scavenging activity, ferric ion reducing power and total phenolic contents.
基金supported by the Key Technique Project from Henan Province, China (152102110045 and 152102310064)
文摘The objective of this study was to isolate lactic acid bacteria(LAB) strains from different origins and to select the best strains for ensiling Robinia pseudoacacia(RB) and Morus alba L.(MB)leaves. The LAB strains were inoculated into the extracted liquid obtained from RB and MB leaves to evaluate the fermentation products. 11 LAB strains were selected for further experiments based on the highest products of lactic or acetic acid, including 1 strain of Weissella confusa, 2 of Lactobacillus reuteri and 8 of Lactobacillus plantarum.The API 50 CH fermentation experiment indicated that all of the selected 11 LAB strains utilised most of the carbohydrates. All the strains grew at temperatures between 10 and 45℃ and at a p H of 3.5 to 4.5; however, L. reuteri F7 and F8 tolerated a p H as low as 3.0. All 11 LAB strains showed antibacterial activity against Listeria monocytogens, Escherichia coil, Salmonella sp. and Acetobacter pasteurianus; however, after excluding the effect of organic acids, only F7 and F8 still exhibited antibacterial activity. The present study indicated that the selected 11 LAB strains could be used to prepare silages of RB and MB leaves, especially L. reuteri F7 and F8.
基金supported by the grants from the Natural Science Foundation of Xinjiang University (070378)
文摘[Objective] The aim of this study was to isolate and identify lactic acid bacteria (LAB) from wheat haulm and to select efficient strains for silage fermentation. [ Method] From 78 LAB strains isolated on the MRS solid medium containing calcium carbonate, we selected 43 strains having better acid-production ability through morphological observation, Gram staining, physiological and biochemical tests, acid production test, acid tolerance test and salt tolerance test. These strains were finally identified by sequencing 16 S rDNA. [ Result] Of the 43 LAB strains having better acid-production ability, 37 belonged to Lactobacillus paracasei subsp., one belonged to Lactobacillus rhamnosus and five belonged to Enterococcus faecium, as shown by the sequences of 16 S rDNA. [ Conclusion ] A total of 43 LAB strains having better acid-production ability were selected, which may be developed as high-quality silage additives.
基金supported by the grants from Application of Nuclear Techniques in Agriculture of the Chinese Ministry of Agriculture (200803034)Natural Science Foundation of Henan Province (2007180048 and 2010B180029)
文摘[Objective] To provide a reference for scientific and rational utilization of forage silage. [Method] The number and species of microorganisms in forage were analyzed, and the characteristics of 11 strains of lactic acid bacteria (LAB) were studied. [ Result] All the isolates were Gram-positive, catalase negative and aeroanaerobic. The isolated strains of homofermentation accounted for 78%. The isolates were divided into three groups, Lactobacillus, Leuconostocaceae and Lactococcus, according to their morphological and biochemical characters. [ Conclusion] The microorganisms in forage in northwest China were isolated and identified, which provides a scientific basis for utilization of forage silage.
文摘Background: Gastric ulcer is one of the most common gastrointestinal diseases with a worldwide prevalence of about 40% in the developed countries and 80% in Africa. Acid inhibitors, anticholinergics, histamine H2-antagonists and antibiotics are commonly used to treat gastric ulcer. However, the accumulating evidence for resistance to antibiotics and the side effects of antibiotics and acid inhibitors, anticholinergics and histamine H2-antagonists. Therefore, there is an urgent need for approaches to treat and prevent gastric ulcer. One alternative strategy is the use of probiotic lactic acid bacteria. Aim of the study: This study aimed to isolate and characterised probiotic lactic acid bacteria from palm wine and fermented milk, and to evaluate their antiulcerogenic potentials on ethanol-induced gastric ulcer in mice. Methods: Probiotic lactic acid bacteria were isolated from the fermented milk and palm wine using pour plate technique on MRS agar and identified using the 16S r RNA gene sequencing. For functional properties and selection, acid and bile salt tolerance were evaluated based on viable colony count on MRS agar. Two probiotic lactic acid bacteria were selected for in vivo studies. Fifty-four healthy young adult Balb/c mice were randomly divided into 9 groups of 6 mice each. Gastric ulcer was induced in mice using one oral dose of absolute ethanol (10 mL/kg body weight). The probiotic lactic acid bacteria (F1 and F2) at different doses (MF3 = 9 × 10<sup>8</sup> CFU/mL, MF6 = 1.8 × 10<sup>9</sup> CFU/mL and MF9 = 2.7 × 10<sup>9</sup> CFU/mL) and omeprazole (20 mg/kg) (a reference drug) were orally administrated daily for 14 days before ulcer induction. These mice were sacrificed 1hour after induction and the stomach contents were collected for volume and pH determination. The stomachs were subjected to macroscopic, biochemical and histopathological analysis. Results: Among the isolates obtained, two were considered to have the best acid and bile tolerance capacity (viable count > 7.5 logCFU/ml) and were identified as Limosilactobacillus fermentum strain BB101 (F1) and Lactobacillus casei strain 02 (F2). Oral administration of probiotics Lactic acid bacteria F1 and F2 significantly attenuated gastric ulcer as revealed by significant reduction (P Conclusion: The results of this study revealed that palm wine and fermented milk are sources of potential probiotic lactic acid bacteria, that is lactobacillus fermentum strain BB101 and Lactobacillus casei 02 with excellent bile and acid tolerance capacity. Also, these probiotic lactic acid bacteria exhibit gastroprotective effect on ethanol-induced gastric ulcer via antioxidant, enhance gastric ulcer healing, antacids, and anti-secretary effects.