Dietary supplemental coated essential oils and organic acids mixture improves growth performance and gut health along with reduces Salmonella load of broiler chickens infected with Salmonella Enteritidis

Background Reducing Salmonella infection in broiler chickens by using effective and safe alternatives to antibiotics is vital to provide safer poultry meat and minimize the emergence of drug-resistant Salmonella and the spread of salmonellosis to humans.This study was to first evaluate the protective efficacy of feeding coated essential oils and organic acids mixture(EOA)on broiler chickens infected with Salmonella Enteritidis(S.Enteritidis,SE),and then its action mechanism was further explored.Methods A total of 4801-day-old Arbor Acres male chickens were randomly assigned into five treatments with six replicates,including non-challenged control fed with basal diet(A),SE-challenged control(B),and SE-infected birds fed a basal diet with 300 mg/kg of EOA(BL),500 mg/kg of EOA(BM)and 800 mg/kg of EOA(BH),respectively.All birds on challenged groups were infected with Salmonella Enteritidis on d 13.Results Feeding EOA showed a reversed ability on negative effects caused by SE infection,as evidenced by decreasing the feed conversion rate(FCR)and the ratio of villus height to crypt depth(VH/CD)(P<0.05),obviously decreasing intestinal and internal organs Salmonella load along with increasing cecal butyric acid-producing bacteria abundance(P<0.05).Moreover,supplemental different levels of EOA notably up-regulated claudin-1(CLDN-1),occludin(OCLN),zonula occludens-1(ZO-1),mucin-2(MUC-2),fatty acid binding protein-2(FABP-2),nuclear factor kappa-light-chainenhancer of activated B cells(NF-κB),myeloid differential protein-88(MyD88)and interleukin-6(IL-6)mRNA levels in the ileum of the infected chickens after challenge,whereas down-regulated toll-like receptor-4(TLR-4)mRNA levels(P<0.05).Linear discriminant analysis combined effect size measurements analysis(LEfSe)showed that the relative abundance of g_Butyricicoccus,g_Anaerotruncus and g_unclassified_f_Bacillaceae significantly was enriched in infected birds given EOA.Also,phylogenetic investigation of communities by reconstruction of unobserved states(PICRUSt)analysis showed that alpha-linolenic acid metabolism,fatty acid metabolism and biosynthesis of unsaturated fatty acids were significantly enriched in the EOA group.Conclusion Our data suggest that the essential oils and organic acids mixture can be used as an effective strategy to ameliorate and alleviate Salmonella Enteritidis infection in broilers.

Dietary organic acids ameliorate high stocking density stress-induced intestinal inflammation through the restoration of intestinal microbiota in broilers

Background:High stocking density(HSD)stress has detrimental effects on growth performance,intestinal barrier function,and intestinal microbiota in intensive animal production.Organic acids(OA)are widely used as feed addi-tives for their ability to improve growth performance and intestinal health in poultry.However,whether dietary OA can ameliorate HSD stress-induced impaired intestinal barrier in broilers remains elusive.In this study,a total of 528 one-day-old male Arbor Acres broilers were randomly allocated into 3 treatments with 12 replicates per treatment including 10 birds for normal stocking density and 17 birds for HSD.The dietary treatments were as follows:1)Normal stocking density+basal diet;2)HSD+basal diets;3)HSD+OA.Results:HSD stress can induce increased levels of serum corticosterone,lipopolysaccharides,interleukin-1β,tumor necrosis factor-α,and down-regulated mRNA expression of ZO-1,resulting in compromised growth performance of broilers(P<0.05).Dietary OA could significantly reduce levels of serum corticosterone,lipopolysaccharides,interleukin-1β,and tumor necrosis factor-α,which were accompanied by up-regulated interleukin-10,mRNA expres-sion of ZO-1,and growth performance(P<0.05).Moreover,OA could down-regulate the mRNA expression of TLR4 and MyD88 to inhibit the NF-κB signaling pathway(P<0.05).Additionally,HSD stress significantly decreased the abundance of Bacteroidetes and disturbed the balance of microbial ecosystems,whereas OA significantly increased the abundance of Bacteroidetes and restored the disordered gut microbiota by reducing competitive and exploita-tive interactions in microbial communities(P<0.05).Meanwhile,OA significantly increased the content of acetic and butyric acids,which showed significant correlations with intestinal inflammation indicators(P<0.05).Conclusions:Dietary OA ameliorated intestinal inflammation and growth performance of broilers through restor-ing the disordered gut microbial compositions and interactions induced by HSD and elevating short-chain fatty acid production to inhibit the TLR4/NF-κB signaling pathway.These findings demonstrated the critical role of intestinal microbiota in mediating the HSD-induced inflammatory responses,contributing to exploring nutritional strategies to alleviate HSD-induced stress in animals.

Formation mechanisms of ethyl acetate and organic acids in Kluyveromyces marxianus L1-1 in Chinese acid rice soup

This study aims to explore the formation mechanism of ethyl acetate and organic acids in acid rice soup(rice-acid soup)inoculated with Kluyveromyces marxianus L1-1 through the complementary analysis of transcriptome and proteome.The quantity of K.marxianus L1-1 varied significantly in the fermentation process of rice-acid soup and the first and third days were the two key turning points in the growth phase of K.marxianus L1-1.Importantly,the concentrations of ethyl acetate,ethanol,acetic acid,and L-lactic acid increased from day 1 to day 3.At least 4231 genes and 2937 proteins were identified and 610 differentially expressed proteins were annotated to 30 Kyoto Encyclopedia of Genes and Genomes(KEGG)pathways based on the analysis results of transcriptome and proteome.The key genes and proteins including up-regulated alcohol dehydrogenase family,alcohol O-acetyltransferase,acetyl-CoA C-acetyltransferase,acyl-coenzyme A thioester hydrolase,and down-regulated aldehyde dehydrogenase family were involved in glycolysis/gluconeogenesis pathways,starch and sucrose metabolism pathways,amino sugar and nucleotide sugar metabolism pathways,tricarboxylic acid(TCA)cycle,and pyruvate metabolism pathways,thus promoting the formation of ethyl acetate,organic acids,alcohols,and other esters.Our results revealed the formation mechanisms of ethyl acetate and organic acids in rice-acid soup inoculated with K.marxianus L1-1.

Dietary encapsulated essential oils and organic acids mixture improves gut health in broiler chickens challenged with necrotic enteritis

Background:The poultry industry is in need of effective antibiotic alternatives to control outbreaks of necrotic enteritis(NE)due to Clostridium perfringens.In the present study,we investigated the effects of dietary supplementation with a blend of encapsulated essential oils and organic acids(BLJ)on growth performance and gut health using a coinfection model of NE in broiler chickens.Methods:Two hundred and eighty-eight one-day-old male Arbor Acres broiler chicks were randomly assigned using a 2×2 factorial design into two groups fed either 0 or 500 mg/kg dietary BLJ and co-challenged(or not challenged for the control)with Eimeria spp./C.perfringens.Results:Infected birds fed the BLJ-supplemented diet exhibited an improved feed conversion ratio throughout the trial(P<0.01),a higher villus height and villus height/crypt depth ratio,and reduced intestinal C.perfringens counts,liver C.perfringens carriage,gut lesion scores and serum fluorescein isothiocyanate dextran(FITC-D)concentrations at 7 d postinfection compared with those of birds without BLJ supplementation(P<0.05).NE-infected birds fed BLJ exhibited significantly upregulated claudin-1 and IGF-2 mRNA levels(P<0.05),increased A20 mRNA expression and significantly downregulated TRAF-6,TNFSF15 and TOLLIP mRNA levels in the jejunum at 7 d post-infection compared with those in birds without BLJ supplementation(P<0.05).Compared with the uninfected and untreated birds,the uninfected birds fed BLJ displayed increased relative abundances of Lactobacillus and Coprococcus but reduced Rikenellaceae levels.Compared with the unsupplemented NE-challenged birds,infected birds fed BLJ showed an increased relative abundance of Unclassified_Lachnospiraceae and a significantly decreased relative abundance of Erysipelotrichaceae.Conclusion:BLJ supplementation improved growth performance and gut health in NE-infected broiler chickens by strengthening the intestinal barrier function,positively modulating the gut microbiota community and differentially regulating intestinal immune responses.Our results also suggested that adding BLJ effectively controlled NE infections after experimental Eimeria and Clostridium perfringens coinfection.

Effect of Zn deficiency and excessive bicarbonate on the allocation and exudation of organic acids in two Moraceae plants

The effect of zinc(Zn) deficiency and excessive bicarbonate on the allocation and exudation of organic acids in plant organs(root, stem, and leaf) and root exudates of two Moraceae plants(Broussonetia papyrifera and Morus alba) were investigated. Two Moraceae plants were hydroponically grown and cultured in nutrient solution in four different treatments with 0.02 mM Zn or no Zn,combined with no or 10 mM bicarbonate. The variations of organic acids in different plant organs were similar to those of root exudates in the four treatments except B. papyrifera, which was in a treatment that was a combination of 0.02 mM Zn and no bicarbonate. The response characteristics in the production, translocation, and allocation of organic acids in the plant organs and root exudates varied with species and treatments. Organic acids in plant organs and root exudates increased under Zn-deficient conditions,excessive bicarbonate, or both. An increase of organic acids in the leaves resulted in an increase of root-exuded organic acids. B. papyrifera translocated more oxalate and citrate from the roots to the rhizosphere than M. alba under the dual influence of 10 mM bicarbonate and Zn deficiency. Organic acids of leaves may be derived from dark respiration and photorespiration. By comparison, organic acids in stems, roots, and root exudates may be derived from dark respiration and organic acid translocation from the leaves. These results provide evidence for the selective adaptation of plants to environments with low Zn levels or high bicarbonate levels such as a karst ecosystem.

Novel additives for the separation of organic acids by ion-pair chromatography

This paper proposes the use of novel surfactant additives for the separation of organic acids by ion-pair chromatography and studies the influences of surfactants on the chromatographic separation behaviors.Researches have been carried out on both silica gel matrix and polymer supporters in order to compare the two ordinary kinds of stationary phases,and the phenomenon is similar. Separation is based on differences in the stabilities of analyte-additive complexes in solution.Retention times of analytes c...

Utilizing Water Treatment Residuals for Phosphorus Removal:Batch Trials,Column Trials and Effects of Three Low-Molecular-Weight Organic Acids

Phosphorus( P) has been recognized as a major limited nutrient responsible for the eutrophication of surface waters. Water treatment residuals( WTRs) are safe by-products of water treatment plants and are cost-efficient adsorbents. In this study, batch experiments and column experiments based on WTRs were employed to study the characteristics of P adsorption and the effects of lowmolecular-weight organic acids( LMWOAs)( citric acid, oxalic acid,and tartaric acid) on P adsorption. Different models of adsorption were used to describe equilibrium and kinetic data. The adsorption data were fitted well by a pseudo-second order kinetic model. The adsorption process was determined to be controlled by three steps of diffusion mechanisms through the intra-particle model.The adsorption equilibrium was well described by the Langmuir,Freundlich,Redlich-Peterson,and Sips isotherm models. Batch and continuous flow experiments indicated that the LMWOAs exhibited inhibitory action,and as pH increased,the inhibitory action became weaker for all the three acids. The effect of LMWOAs concentration was not significant on inhibition. The effects of LMWOAs were closely related to reaction time.

Influence of Potassium Nutrition and Exogenous Organic Acids on Iron Uptake by Monocot and Dicot Plants

Iron (Fe) is a vital element for the survival and proliferation of all plants;therefore, Fe-biofortification by the application of chemical and organic fertilizers is being as an effective approach to fight hidden hunger retards the growth and development of crop plants. Two experiments were carried out to investigate the effect of potassium and exogenous organic acids on iron uptake by two different plants: one is monocotyledon, maize (Zea mays L.) and the second is dicotolydon pea (Pisum sativum L.) grown under controlled conditions. The seedlings were grown in sand culture in a greenhouse experiment and irrigated with one-tenth strength modified nutrient solution of Hoagland and Arnon as a base solution (pH 7.5), containing different iron treatments (0, 1, and 5 ppm as FeSO4·7H2O) combined with potassium nutrition (0, 5, 10, and 50 ppm as K2SO4). After 30 days, the best interaction treatment was selected for further experiment including 5.0 ppm Fe as FeSO4.7H2O and 50 ppm K as K2SO4 in combination with 1 × 10-5 mole/liter of one of the following organic acids: Citric acid, Oxalic acid, Formic acid, Acetic acid, Propionic acid, Tartaric acid, Succinic acid, Fumaric acid, Malic acid, Glutamic acid, besides the free organic acid nutrient solution as a control. Results revealed that the interaction between 5.0 ppm Fe and 50 ppm K was the best interaction treatment for increasing biomass production and iron uptake of maize and pea seedlings under applied condition. Furthermore, exogenous application of organic acids improves uptake and translocation of nutrient such as iron, potassium and phosphorus by the maize and pea plants. In conclusion, potassium nutrition and exogenous organic acids have the potential to stimulate Fe-uptake of monocot and dicot plants and mediate iron-biofortified crops.

Spatial Distribution Characteristics of Organic Acids in Two Late-blooming Rhododendron Species

[Objectives]The spatial distribution characteristics of organic acids in two late-blooming Rhododendron species(Rhododendron decorum and Rhododendron stamineum)in Guizhou Baili Rhododendron National Forest Park were explored,in order to provide reference for exploring the plant-soil relationship of subtropical forest.[Methods]The fresh leaf,stem,root,litter,humus and soil samples of R.decorum and R.stamineum were collected.The contents of eight low molecular weight organic acids including oxalic acid,tartaric acid,malic acid,citric acid,acetic acid,lactic acid,succinic acid and formic acid were determined by high performance liquid chromatography(HPLC).[Results]Oxalic acid is the main organic acid in the two species of Rhododendron.Among different samples,the content of organic acids was in the following order:root>fresh leaf>humus>litter>stem>soil.[Conclusions]The content of organic acids in the root was significantly higher than that in other parts.The types of organic acids in stems were the least.

Edible Ectomycorrhizal Mushrooms Russula spp. of Côte d’Ivoire: Total Phenolic Content, HPLC-Profiles of Phenolic Compounds and Organic Acids, Antioxidant Activities

The aim of this study was to investigate the phenolic compounds content, HPLC-profiles of phenolic compounds and organic acids, and also antioxidant activities via the ability to scavenge DPPH radical of three wild edible mushrooms belonging to Russula genus and being collected in center of Côte d’Ivoire. Total phenolic compounds, flavonoids and tannins contents of methanolic extracts were assessed by colorimetric assays. So, the obtained values of these chemical parameters ranged from 394.05 to 513.50 mg/100 g DW, 94.50 to 139.95 mg/100 g DW and from 124.20 to 165 ± 0.54 mg/100 g DW, respectively. Otherwise, HPLC-profiles of the methanolic extracts revealed that quercetin, salicylic acid and tannin ol were the main phenolic compounds in R. delica whereas R. lepida contained gallic acid, catechin and protocatechuic acid as main phenolic compounds. Besides, it showed that the phenolic compounds such as salicylic acid, tannin ol and catechin were observed in R. mustelina. As for HPLC-profiles of organic acid, the fumaric and malic acid were recorded as the main organic acids in the three species of wild edible mushrooms. However, citric acid content was found to be highest in R. lepida. The methanolic extracts of the three mushrooms exhibited high DPPH radical scavenging activities ranging from 74.92% to 58.92%. These wild edible mushrooms could be considered a potential supply source of adequate natural antioxidant for local population.

Ability of Agrogyron elongatum to accumulate the single metal of cadmium, copper, nickel and lead and root exudation of organic acids

Agrogyron elongatum were grown in nutrient solution containing moderate to high amounts of separate heavy metal of Cd, Cu, Ni and Pb in a greenhouse for a 9-day. Cd, Cu, Ni and Pb generally led to decrease in the elongation of roots although the length of seedlings exposed to Cd and Pb at 0.05 and 0 5 mg/L showed to be slightly greater than that of controls. Of the four metals in the experiment, Pb was absorbed and accumulated to the highest level, with the concentrations of 92754 mg/kg dry weight (DW) in roots and 11683 mg/kg DW in shoots. Cd was moderately accumulated in Agrogyron elongatum, but the maximum bioaccumulation coefficients (BCs) for roots and shoots were observed. The patterns for Cu and Ni uptake and distribution in plants differed from those of Pb and Cd, as it was showed that the shoot accumulation of Cu and Ni was significantly higher than in roots. A. elongatum had the highest Ni concentration in shoots (30261 mg/kg DW) at the external concentration of 250 mg/L. Cu ranked second, with a shoot concentration of 12230 mg/kg DW when 50 mg/L Cu in solution was applied. For the four trace elements tested, the highest concentrations in shoots decreased by the order of Ni>Cu>Pb>Cd (mg/kg DW), and those in roots were Pb>Cd>Ni>Cu (mg/kg DW). Malic, oxalic and citric acids exuded by roots exposed to 1 and 50 mg/L of the metals were detected. Release of organic acids from plants significantly differed among the metal treatments. Cu was most effectively in inducing root exudation of the three types of organic acids. Cd, and Ni were also the inducers of secretion of malic and oxalic acids. With reference of Pb, a small amounts of malic and oxalic acids were detected in the root exudates, but few quantities of citric acid were found. However, no correlation between alternations in root exudation of organic acids and metal accumulation could be established.

Microencapsulated essential oils combined with organic acids improves immune antioxidant capacity and intestinal barrier function as well as modulates the hindgut microbial community in piglets

Background:The objective of this experiment was to evaluate the effect of a combination of microencapsulated essential oils and organic acids(MOA)on growth performance,immuno-antioxidant status,intestinal barrier function and microbial structure of the hindgut in piglets.A total of 120 piglets(Duroc×[Landrace×Yorkshire];weighted 7.66±1.79 kg,weaned at d 28)were randomly selected and allocated to 3 treatments with 4 replicates per group and 10 piglets per replicate according to the initial body weight and gender.The dietary treatments were as follows:1)basal diet(Ctrl);2)Ctrl+chlortetracycline(75 mg/kg)(AGP);3)Ctrl+MOA(1500 mg/kg).The experiment period was lasted for 21 d.Results:Compared to the Ctrl group,dietary supplemented MOA alleviated(P<0.05)the diarrhea rate from d 12 to 21,enhanced(P<0.05)the concentration of serum interlukin-10 and glutathione peroxidase in piglets on d 11 after weaning and serum superoxide dismutase in 21-day piglets.The MOA group also improved(P<0.05)the apparent digestibility of dry matter(DM),organic matter(OM)and gross energy(GE),up-regulated(P<0.05)the mRNA expression level of occludin,claudin-1 and mucin-2 in ileum and increased(P<0.05)the contents of propionic and butyric acids in the cecum of piglets.The MOA group modulated the cecal and colonic microbial community structure and increased(P<0.05)the abundance of Faecalibacterium and Muribaculaceae in cecum and Streptococcus and Weissella in colon.Additionally,AGP group decreased(P<0.05)apparent digestibility of DM,OM and GE as well as down-regulated(P<0.05)relative gene expression level of claudin-1 in duodenum and jejunum,ZO-1 and mucin-1 in jejunum of piglets.Conclusion:In summary,dietary supplemented MOA alleviated diarrhea and improved nutrient apparent digestibility in piglets via enhancing immuno-antioxidant properties,increasing digestive enzyme activity,upregulating the expression of intestinal barrier-related genes,and modifying the microbial community structure of the cecum and colon.Therefore,dietary supplementation with MOA as an alternative to antibiotics was feasible to improve intestinal health of piglets in practical production.

Evaluating organic acids as alternative leaching reagents for rare earth elements recovery from NdFeB magnets

This study proposes an advanced leaching method using organic acids to recover rare earth elements(REEs)from NdFeB permanent magnets from end-of-life computers hard disk drives(HDDs).The end-oflife HDDs were first dismantled in order to recover NdFeB magnets,which were then thermally demagnetized at 350℃during 30 min before crushing in a ball mill under inert atmosphere.Scanning electron microscopy/energy dispersive X-ray spectroscopy(SEM/EDS)analyses performed on the NdFeB magnets show the heterogeneous structure containing the major matric phase Nd_(2)Fe_(14)B and the REEsrich phase containing Nd and Pr oxides.Additionally,X-ray diffraction(XRD)and Mossbauer spectroscopy(MS)analyses on the ground NdFeB magnet show that grinding NdFeB magnets under inert atmosphere helps to minimize its oxidation.Chemical analysis shows that the composition of the ground sample is Nd:22.8 wt%,Pr:3.3 wt%,Dy:1.2 wt%,Fe:62.6 wt%,Co:1.5 wt%,B:0.9 wt%,Ni:0.6 wt%.Diagrams of speciation and equilibrium phases(E_(h) vs.pH)were calculated to determine the predominance of the formed species in the REEs-organic acids systems.The influence of the organic acid type(acetic acid,formic acid,citric acid and tartaric acid),the acid concentration(10 vol%,up to saturation),and the solid/liquid(S/L)ratio(0.5%-10%)on NdFeB magnets leaching was investigated employing an optimal experimental design conceived by the statistical software JMP.Acetic acid(CH_(3)COOH)shows the highest leaching performance of REEs,allowing leaching yields over 90%for Nd,Dy and Pr in the acid concentration range of 1.6-10 mol/L and the S/L ratio range of 0.5%-5%at a temperature of 60℃.The results presented in this investigation suggest that REEs can be recovered from magnets of end-of-life HDDs using an eco-friendly method assisted by organic acids.

Leaching recovery of rare earth elements from the calcination product of a coal coarse refuse using organic acids

Due to the increasing criticality of rare earth elements(REEs),it has become essential to recover REEs from alternative resources.In this study,systematic REEs leaching tests were performed on the calcination product of a coal coarse refuse using hydrochloric acid and different types of organic acid as lixiviants.Experimental results show that the recovery of REEs,especially heavy REEs(HREEs)and scandium(Sc),is improved by using selected organic acids.Citric acid and DL-malic acid afford the best leaching performances;whereas,malonic acid,oxalic acid,and DL-tartaric acid are inferior to hydrochloric acid.Results of zeta potential measurements and solution chemical equilibrium calculations show that malonic acid is more likely adsorbed on the surface of the calcined material compared with citric acid and DL-malic acid.The adsorption may reduce the effective concentration of malonic species in solution and/or increase the amount of REEs adsorbed on the surface,thereby impairing the leaching recovery.Compared with light REEs(LREEs),a stronger adsorption of the HREEs on the surface is observed from electro-kinetic test results.This finding explains why organic acids impose a more positive impact on the leaching recovery of HREEs,By complexing with the HREEs,organic acids can keep the metal ions in solution and improve the leaching recovery.The adsorption of Sc^(3+)on the surface is the lowest compared with other REEs.Therefore,rather than complexing,the organic anionic species likely play a function of solubilizing Sc from the solid,which is similar to that of hydrogen ions.

A theoretical study of hydrogen-bonded molecular clusters of sulfuric acid and organic acids with amides

Amides,a series of significant atmospheric nitrogen-containing volatile organic compounds(VOCs),can participate in new particle formation(NPF)throught interacting with sulfuric acid(SA)and organic acids.In this study,we investigated the molecular interactions of formamide(FA),acetamide(AA),N-methylformamide(MF),propanamide(PA),Nmethylacetamide(MA),and N,N-dimethylformamide(DMF)with SA,acetic acid(HAC),propanoic acid(PAC),oxalic acid(OA),and malonic acid(MOA).Global minimum of clusters were obtained through the association of the artificial bee colony(ABC)algorithm and density functional theory(DFT)calculations.The conformational analysis,thermochemical analysis,frequency analysis,and topological analysis were conducted to determine the interactions of hydrogen-bonded molecular clusters.The heterodimers formed a hepta or octa membered ring through four different types of hydrogen bonds,and the strength of the bonds are ranked in the following order:SO-H···O>CO-H···O>N-H···O>C-H···O.We also evaluated the stability of the clusters and found that the stabilization effect of amides with SA is weaker than that of amines with SA but stronger than that of ammonia(NH 3)with SA in the dimer formation of nucleation process.Additionally,the nucleation capacity of SA with amides is greater than that of organic acids with amides.

Organic acids production from lactic acid bacteria:A preservation approach

The lactic acid bacteria(LAB)are a group of gram-positive bacteria capable of converting carbohydrate substrates into organic acids and producing a wide range of metabolites.Organic acids,including propionic,formic,acetic acid,and lactic acid,create an unfavorable environment for the growth of spoilage and pathogenic microorganisms.Also,they are employed as monomers or starting ingredients for food-based supplements,biomaterials,and biodegradable polymers.Organic acids from LAB have the potential to prevent spoilage and improve food taste that enhances consumer acceptance and appeal.Organic acids can be useful as starting materials in multiple applications,including food,chemical,cosmetic,pharmaceutical,and beverage industries owing to their various functional properties.Additionally,the use of LAB for organic acids production can replace petroleum-based processes due to their ability to utilize inexpensive and renewable feedstocks.This article aims to provide the potential of LAB as a biological catalyst for producing different organic acids.Also,the current review will give a critical snapshot of the strategies to improve microbial organic acid production and potential application of organic acids and discuss new challenges and opportunities for developing novel economically effective and sustainable nutritional sources and techniques.

Effect of struvite and organic acids on immobilization of copper and zinc in contaminated bio-retention filter media

Few studies have been carried out to connect nutrient recovery as struvite from wastewater and sustainable utilization of the recovered struvite for copper and zinc immobilization in contaminated soil.This study revealed the effect of struvite on Cu and Zn immobilization in contaminated bio-retention soil in the presence of commonly exuded plant organic acids.The research hypothesis was that the presence of both struvite and organic acids may influence the immobilization of Cu and Zn in soil.The outcome of this research confirmed that more than 99%of Cu and Zn was immobilized in bio-retention filter media by struvite application.Water-soluble Cu and Zn concentrations of struvite treated soil were less than 1.83 and 0.86 mg/kg respectively,and these concentrations were significantly lower compared to the total Cu and Zn content of 747.05 mg/kg in the contaminated soil.Application of struvite to Cu-and Zn-contaminated soil resulted in formation of compounds similar to zinc phosphate tetrahydrate(Zn3(PO4)2·4H2O)and amorphous Cu and Zn phases.Struvite was effective in heavy metal remediation in acidic soil regardless of the presence of Ca impurities in struvite and the presence of plant organic acids in soil.Overall,this study revealed that struvite recovered from wastewater treatment plants has potential for use as an amendment for heavy metal remediation in contaminated bio-retention soil.

Atmospheric gaseous organic acids in winter in a rural site of the North China Plain

Organic acids are important contributors to the acidity of atmospheric precipitation,but their existence in the Chinese atmosphere is largely unclear.In this study,twelve atmospheric gaseous organic acids,including C_(1)-C_(9) alkanoic acids,methacrylic acid,pyruvic acid,and benzoic acid,were observed in the suburb of Wangdu,Hebei Province,a typical rural site in the northern China plain from 16^(th) December,2018 to 22^(nd) January,2019,using a Vocus■ Proton-Transfer-Reaction time-of-flight mass spectrometer(Vocus PTR-ToF).The quantification of C_(2)-C_(4) alkanoic acids by the Vocus PTR-ToF was calibrated according to the titration of a NaOH solution by C_(2)-C_(4) alkanoic acids from home-made permeation sources,and the other organic acids except for formic acid were quantified based on the k_(cap)-sensitivity linearity in the Vocus PTR-ToF,whereas formic acid was not quantified because our instrument setting led to a significant underestimation in its concentration.The average total concentration of eleven gaseous organic acids was 6.96±5.20 ppbv(parts per billion by volume).The average concentration of acetic acid was the highest(3.86±3.00 ppbv),followed by propanoic acid,butyric acid,and methacrylic acid.Domestic straw burning was likely the dominant source of the observed gaseous organic acids according to the good correlations between acetonitrile and organic acids and between particulate K+and organic acids,and traffic emissions could also have contributed.During episodes with continuously high concentrations of organic acids,short-distance transport dominated in Wangdu according to the backward trajectory analysis.Baoding,Shijiazhuang,and Hengshui areas were the main source areas based on potential source contribution function and concentration weighing track analysis.

Effects of low molecular weight organic acids on aggregation behavior of biochar colloids at acid and neutral conditions

Low molecular weight organic acids(LMWOAs),as active components in the rhizosphere carbon cycling,may influence the environmental behaviors of biochar colloids.This study selected the pine-wood and wheat-straw biochars(PB and WB)as two typical biochars.The effects of typical LMWOAs(oxalic acid,citric acid,and malic acid)on aggregation kinetics of PB and WB colloids were investigated under pH 4 and 6 conditions.Critical coagulation concentrations(CCCs)of both PB and WB colloids were decreased with the LMWOAs regardless of the types of biochar and the solution pH,and the most significant effect occurred in pH 4 due to more LMWOAs sorption on the biochar colloids.The different types of LMWOAs caused various CCCs changes.For example,the CCC values of PB colloids decreased from 75 mM to 56,52,and 47 mM in the pH 4 NaCl solutions when 1 mM oxalic acid,citric acid,and malic acid were present in the suspensions,respectively.The chemical structure(functional groups)and molecular weight of LMWOAs,solution pH,and the electrophoretic mobility(EPM)of biochar co-influence the interactions between biochar colloids and LMWOAs,thus affecting the stability of biochar colloids in the presence of LMWOAs.The presence of LMWOAs accelerated the aggregation of colloidal biochar by increasing the interaction of surface bridging bonds(hydrogen bonding)and decreasing the repulsive force between colloidal biochar particles.This study showed that LMWOAs could accelerate the aggregation of biochar colloids in acidic or neutral environments and reduce the mobility of biochar colloids in soil rhizosphere.

Transformation and immobilization of hexavalent chromium in the co-presence of biochar and organic acids:effects of biochar dose and reaction time

A batch experiment was conducted to examine the effects of biochar dose and reaction duration on the transformation and immobilization of Cr(VI)in the combined biochar and low-molecular-weight organic acid systems.The results showed that increase in the dosage level of biochar caused increase in the solution pH,particularly for the Biochar300 treatments but did not enhance the reduction of Cr(VI)after 1-day reaction.Over 35%of the converted Cr(III)was immobilized by sorption to the biochar due to increased negatively charged sites on the biochar surfaces driven by pH rise.The elevated pH due to biochar dose increase tended to slow down the reduction of Cr(VI)to Cr(III),resulting in more Cr(VI)being adsorbed at a higher biochar dose.For the higher-temperature biochars,the increase in biochar dose did not markedly change the transformation and immobilization of the added Cr.Increase in the reaction duration markedly increased the pH for Biochar300.This resulted in the disappearance of all Cr(VI)in the solution after the 7-day reaction,possibly through sorption of cationic Cr(III)to the biochar surfaces.Increase in reaction time for the higher-temperature biochars resulted in re-oxidation of Cr(III)to Cr(VI)due to the increased exposure of solution Cr(III)to atmospheric oxygen.The research findings obtained from this study have implications for optimizing treatment procedure for wastewater that contains elevated level of toxic Cr(VI).Simulation experiments are required to determine appropriate biochar dose and reaction time to achieve cost-effective treatment goals.