Pathogenic microorganisms produce numerous metabolites,including volatile organic compounds(VOCs).Monitoring these metabolites in biological matrices(e.g.,urine,blood,or breath)can reveal the presence of specific micr...Pathogenic microorganisms produce numerous metabolites,including volatile organic compounds(VOCs).Monitoring these metabolites in biological matrices(e.g.,urine,blood,or breath)can reveal the presence of specific microorganisms,enabling the early diagnosis of infections and the timely implementation of tar-geted therapy.However,complex matrices only contain trace levels of VOCs,and their constituent com-ponents can hinder determination of these compounds.Therefore,modern analytical techniques enabling the non-invasive identification and precise quantification of microbial VOCs are needed.In this paper,we discuss bacterial VOC analysis under in vitro conditions,in animal models and disease diagnosis in humans,including techniques for offline and online analysis in clinical settings.We also consider the advantages and limitations of novel microextraction techniques used to prepare biological samples for VOC analysis,in addition to reviewing current clinical studies on bacterial volatilomes that address inter-species in-teractions,the kinetics of VOC metabolism,and species-and drug-resistance specificity.展开更多
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
Forty-six candidate phenol/benzoate degrading-iron reducing bacteria were isolated from long term irrigated tropical paddy soils by enrichment procedures.Pure cultures and some prepared mixed cultures were examined fo...Forty-six candidate phenol/benzoate degrading-iron reducing bacteria were isolated from long term irrigated tropical paddy soils by enrichment procedures.Pure cultures and some prepared mixed cultures were examined for ferric oxide reduction and phenol/benzoate degradation.All the isolates were iron reducers,but only 56.5%could couple iron reduction to phenol and/or benzoate degradation,as evidenced by depletion of phenol and benzoate after one week incubation.Analysis of degradative capability using Biolog...展开更多
Lignin is one of the most abundant biomasses in nature. It is composed of aromatic moieties and has great potential for use in the production of chemical alternatives to petroleum products. Because of increasing inter...Lignin is one of the most abundant biomasses in nature. It is composed of aromatic moieties and has great potential for use in the production of chemical alternatives to petroleum products. Because of increasing interest in biocatalysis, the potential for industrial application of microbial metabolism of lignin-derived compounds has gained considerable recent attention. Functional screenings of culturable bacteria isolated from sediments and sunken wood collected from the deep sea revealed the existence of a number of previously unidentified bacteria capable of metabolizing lignin-related aromatic compounds. Of the 510 isolates obtained in the present study, 208 completely or partially metabolized these compounds. The 208 isolates were classified into diverse phyla, including Firmicutes, Actinobacteria, Bacteroidetes, and Proteobacteria. Among the 208 isolates, 61 unique 16S rRNA gene sequences were detected including previously unidentified marine lineage isolates. The metabolites of the isolates were analysed using liquid chromatography/mass spectrometry (LC/MS) or gas chromatography/mass spectrometry (GC/MS). Most of the representative 61 isolates non-oxidatively decarboxylated the substrates to produce the corresponding aromatic vinyl monomers, which are used as feed stocks for bio-based plastics production. Oxidative metabolism of the lignin-related compounds for assimilation was frequently observed. Our study showed that the deep-sea environment contains an abundance of microorganisms capable of both non-oxidative and oxidative bioconversion of lignin-derived aromatic compounds. The ability for bio-conversion of aromatic compounds found in this study will facilitate the development of future biotechnological applications.展开更多
The flucculation efficiency of compound bioflocculant produced by flocculant-producing bacteria was investigated in this study. Cheap cellulose was selected as the substrate for the production of a lower cost bioflocc...The flucculation efficiency of compound bioflocculant produced by flocculant-producing bacteria was investigated in this study. Cheap cellulose was selected as the substrate for the production of a lower cost bioflocculant. The end product of cellulose decomposing bacteria was utilized as substrate for flocculant-producing bacteria. The optimum fermentation conditions were determined as follows: the initial fermentation and fermentation time was 5 d and 1 d respectively, the temperature was 30 ℃, the rotation speed was 120 r/min, the amount of CaCl2 solution ( 10% ) was 1.5 ml/L. The flocculation test indicated that the bioflocculant had high efficiency in the removal of the turbldity raw water from Songhua River.展开更多
The entire fermentation process of traditional Chinese broad bean paste with chili comprises three individual stages:Tianbanzi,chili pei,and paste fermentation(Tianbanzi-chili pei mixture).Three stages share average 7...The entire fermentation process of traditional Chinese broad bean paste with chili comprises three individual stages:Tianbanzi,chili pei,and paste fermentation(Tianbanzi-chili pei mixture).Three stages share average 77.53%of all bacteria(89 genera),indicating that the similar environment leads to the similar bacterial communities.One,one,and three genera are exclusive to Tianbanzi,chili pei,and paste stages,respectively,due to the special physical and chemical properties for each stage.Total acidity,pH,and NaCl are important endogenous factors that promote the succession of bacterial communities.According to the dynamics of organic acids,reducing sugars,amino acids,and volatile compounds,60-,210-,and 180-day are considered the best fermentation periods for Tianbanzi,chili pei,and paste,respectively,to balance time cost and product quality.Three(Tetragenococcus,Lactobacillus,and Pseudomonas),four(Tetragenococcus,Lactobacillus,Bacillus,and Pseudomonas),and five(Tetragenococcus,Lactobacillus,Bacillus,Pseudomonas,and Pediococcus)genera are considered the core functional bacteria of Tianbanzi,chili pei,and paste fermentation,respectively.展开更多
Antibacterial and antifungal activities of 32 organic and 14 peptidic extracts obtained from twelve endophytic fungi of the Collection of Endophytes Quito-Catolica were tested against the pathogenic bacteria <i>...Antibacterial and antifungal activities of 32 organic and 14 peptidic extracts obtained from twelve endophytic fungi of the Collection of Endophytes Quito-Catolica were tested against the pathogenic bacteria <i>Staphylococcus aureus</i>, Pseudomonas aeruginosa, Serratia marcescens, Escherichia coli and <i>Salmonella enteritidis</i>, and against the fungal oomycete <i>Pythium ultimum</i>. It was observed that the extracts of <i>Marasmiellus candidus</i> (CEQCA-O1113), <i>Xylaria laevis</i> (CEQCA-O1399), <i>Fusarium solani</i> (CEQCA-O1393), <i>Diaporthe helianthi</i> (CEQCA-O1394) and <i>Xylaria</i> sp. (CEQCA-O1400) partially or totally inhibited the microorganisms tested. The extracts CEQCA-O1399.P1 and CEQCA-O1113.D1 showed fungistatic and fungicidal effects against <i>P. ultimum</i>, respectively. Six extracts strongly inhibited <i>S. aureus</i>, and <i>E. coli</i> was strongly inhibited by the extract CEQCA-O1113.E2. Based on a bioassay-guided approach, the extracts with strong bioactivity in the antibacterial assays by an agar diffusion method were also tested by a disk diffusion method, and the minimal inhibitory concentrations were determined by a microdilution assay. The most bioactive extract, CEQCA-O1113.D1, was also purified by high performance liquid chromatography. The extract recovered its initial bioactivity against <i>S. aureus</i> in two fractions after the purification. Overall, the results of this study highlight the potential of the fungal endophytes as producers of bioactive compounds.展开更多
Sourdough starters for making traditional steamed bread are rich in microbes.Studies have shown that,in addition to yeast and lactic acid bacteria(LAB),acetic acid bacteria(AAB)are other functional species in sourdoug...Sourdough starters for making traditional steamed bread are rich in microbes.Studies have shown that,in addition to yeast and lactic acid bacteria(LAB),acetic acid bacteria(AAB)are other functional species in sourdough,but the influences of AAB on the properties of sourdough and steamed bread were rarely reported.This study aimed to assess the effects of a selected strain of acetic acid bacterium on the properties of sourdough and steamed bread.Sourdoughs and steamed breads were prepared from five different starter cultures,marked as CK(control check,with no starters),Y(only yeast),YL(yeast+LAB),YA(yeast+AAB)and YLA(yeast+LAB+AAB),and their properties were determined.The results of sour dough properties showed that the YLA sourdough had the highest total titratable acid of 14.6 mL and the lowest pH of 3.87 compared with the other groups after fermentation to 8 h;and the YLA sourdough had the greatest elasticity and viscosity.The results of quality properties of steamed bread revealed that the L*value(88.40±0.09)of the YA steamed bread was significantly higher than those of the YLA and YL steamed breads;the YLA steamed bread had the highest specific volume and the highest sensory score of 89.6±3.31 in comparison to those of the other groups;the hardness and chewiness of YLA and YA steamed breads were significantly lower than those of the other groups.Volatile compounds in the steamed breads were also determined by SPME-GC-MS.A total of 42 flavor substances were detected,including 3 kinds of alcohols,8 kinds of aldehydes,7 kinds of ketones,2 kinds of acids,15 kinds of esters,1 furan,and 6 kinds of other types of compounds,mainly alkanes and esters,followed by alcohols and aldehydes.The YLA steamed bread was richer in esters,aldehydes,and acids than those from the other treatment groups.By contrast,alkanes and aldehydes were dominant in the Y and YL steamed breads.Therefore,the flavor and quality of the steamed bread made from the YLA sourdough could be improved obviously.These results could provide references for the application of AAB in dough fermentation and the improvement of new kinds of starters.展开更多
The paper presents data about the antimicrobial activity of the autochthonous compound of taninic source Enoxil. The minimal inhibitory and bactericidal/fungicidal concentrations were established for some skin and wou...The paper presents data about the antimicrobial activity of the autochthonous compound of taninic source Enoxil. The minimal inhibitory and bactericidal/fungicidal concentrations were established for some skin and wound infectious agents. It was established, based on Pseudomonas bacteria model, that the Enoxil compound suppress the activity of some important enzymes—a phenomenon that leads to the increase of bacterial sensibility to many tested antibiotics.展开更多
基金funded by the National Science Centre,Poland(Project No.:2017/26/D/NZ6/00136).
文摘Pathogenic microorganisms produce numerous metabolites,including volatile organic compounds(VOCs).Monitoring these metabolites in biological matrices(e.g.,urine,blood,or breath)can reveal the presence of specific microorganisms,enabling the early diagnosis of infections and the timely implementation of tar-geted therapy.However,complex matrices only contain trace levels of VOCs,and their constituent com-ponents can hinder determination of these compounds.Therefore,modern analytical techniques enabling the non-invasive identification and precise quantification of microbial VOCs are needed.In this paper,we discuss bacterial VOC analysis under in vitro conditions,in animal models and disease diagnosis in humans,including techniques for offline and online analysis in clinical settings.We also consider the advantages and limitations of novel microextraction techniques used to prepare biological samples for VOC analysis,in addition to reviewing current clinical studies on bacterial volatilomes that address inter-species in-teractions,the kinetics of VOC metabolism,and species-and drug-resistance specificity.
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.
文摘Forty-six candidate phenol/benzoate degrading-iron reducing bacteria were isolated from long term irrigated tropical paddy soils by enrichment procedures.Pure cultures and some prepared mixed cultures were examined for ferric oxide reduction and phenol/benzoate degradation.All the isolates were iron reducers,but only 56.5%could couple iron reduction to phenol and/or benzoate degradation,as evidenced by depletion of phenol and benzoate after one week incubation.Analysis of degradative capability using Biolog...
文摘Lignin is one of the most abundant biomasses in nature. It is composed of aromatic moieties and has great potential for use in the production of chemical alternatives to petroleum products. Because of increasing interest in biocatalysis, the potential for industrial application of microbial metabolism of lignin-derived compounds has gained considerable recent attention. Functional screenings of culturable bacteria isolated from sediments and sunken wood collected from the deep sea revealed the existence of a number of previously unidentified bacteria capable of metabolizing lignin-related aromatic compounds. Of the 510 isolates obtained in the present study, 208 completely or partially metabolized these compounds. The 208 isolates were classified into diverse phyla, including Firmicutes, Actinobacteria, Bacteroidetes, and Proteobacteria. Among the 208 isolates, 61 unique 16S rRNA gene sequences were detected including previously unidentified marine lineage isolates. The metabolites of the isolates were analysed using liquid chromatography/mass spectrometry (LC/MS) or gas chromatography/mass spectrometry (GC/MS). Most of the representative 61 isolates non-oxidatively decarboxylated the substrates to produce the corresponding aromatic vinyl monomers, which are used as feed stocks for bio-based plastics production. Oxidative metabolism of the lignin-related compounds for assimilation was frequently observed. Our study showed that the deep-sea environment contains an abundance of microorganisms capable of both non-oxidative and oxidative bioconversion of lignin-derived aromatic compounds. The ability for bio-conversion of aromatic compounds found in this study will facilitate the development of future biotechnological applications.
基金Sponsored by the Science Foundation of Heilongjiang Province(Grant No.GB02C202 -02).
文摘The flucculation efficiency of compound bioflocculant produced by flocculant-producing bacteria was investigated in this study. Cheap cellulose was selected as the substrate for the production of a lower cost bioflocculant. The end product of cellulose decomposing bacteria was utilized as substrate for flocculant-producing bacteria. The optimum fermentation conditions were determined as follows: the initial fermentation and fermentation time was 5 d and 1 d respectively, the temperature was 30 ℃, the rotation speed was 120 r/min, the amount of CaCl2 solution ( 10% ) was 1.5 ml/L. The flocculation test indicated that the bioflocculant had high efficiency in the removal of the turbldity raw water from Songhua River.
基金supported by the National Key R&D Program of China(2016YFD0400505)China Postdoctoral Science Foundation(2018M640241)+2 种基金Tianjin Postdoctoral Foundation(TJQYBSH2018010)Tianjin Municipal Education Commission(TD13-5013,2018ZD08)Key Laboratory of Industrial Fermentation Microbiology,Education Ministry of China(2018KF005)。
文摘The entire fermentation process of traditional Chinese broad bean paste with chili comprises three individual stages:Tianbanzi,chili pei,and paste fermentation(Tianbanzi-chili pei mixture).Three stages share average 77.53%of all bacteria(89 genera),indicating that the similar environment leads to the similar bacterial communities.One,one,and three genera are exclusive to Tianbanzi,chili pei,and paste stages,respectively,due to the special physical and chemical properties for each stage.Total acidity,pH,and NaCl are important endogenous factors that promote the succession of bacterial communities.According to the dynamics of organic acids,reducing sugars,amino acids,and volatile compounds,60-,210-,and 180-day are considered the best fermentation periods for Tianbanzi,chili pei,and paste,respectively,to balance time cost and product quality.Three(Tetragenococcus,Lactobacillus,and Pseudomonas),four(Tetragenococcus,Lactobacillus,Bacillus,and Pseudomonas),and five(Tetragenococcus,Lactobacillus,Bacillus,Pseudomonas,and Pediococcus)genera are considered the core functional bacteria of Tianbanzi,chili pei,and paste fermentation,respectively.
文摘Antibacterial and antifungal activities of 32 organic and 14 peptidic extracts obtained from twelve endophytic fungi of the Collection of Endophytes Quito-Catolica were tested against the pathogenic bacteria <i>Staphylococcus aureus</i>, Pseudomonas aeruginosa, Serratia marcescens, Escherichia coli and <i>Salmonella enteritidis</i>, and against the fungal oomycete <i>Pythium ultimum</i>. It was observed that the extracts of <i>Marasmiellus candidus</i> (CEQCA-O1113), <i>Xylaria laevis</i> (CEQCA-O1399), <i>Fusarium solani</i> (CEQCA-O1393), <i>Diaporthe helianthi</i> (CEQCA-O1394) and <i>Xylaria</i> sp. (CEQCA-O1400) partially or totally inhibited the microorganisms tested. The extracts CEQCA-O1399.P1 and CEQCA-O1113.D1 showed fungistatic and fungicidal effects against <i>P. ultimum</i>, respectively. Six extracts strongly inhibited <i>S. aureus</i>, and <i>E. coli</i> was strongly inhibited by the extract CEQCA-O1113.E2. Based on a bioassay-guided approach, the extracts with strong bioactivity in the antibacterial assays by an agar diffusion method were also tested by a disk diffusion method, and the minimal inhibitory concentrations were determined by a microdilution assay. The most bioactive extract, CEQCA-O1113.D1, was also purified by high performance liquid chromatography. The extract recovered its initial bioactivity against <i>S. aureus</i> in two fractions after the purification. Overall, the results of this study highlight the potential of the fungal endophytes as producers of bioactive compounds.
基金supported by Young Key Teachers Training Program of Henan University of Technology and Young Key Teachers Cultivation Plan in Colleges and Universities of Henan province (2019GGJS-088)sponsored by Natural Science Foundation of Henan(202300410113)
文摘Sourdough starters for making traditional steamed bread are rich in microbes.Studies have shown that,in addition to yeast and lactic acid bacteria(LAB),acetic acid bacteria(AAB)are other functional species in sourdough,but the influences of AAB on the properties of sourdough and steamed bread were rarely reported.This study aimed to assess the effects of a selected strain of acetic acid bacterium on the properties of sourdough and steamed bread.Sourdoughs and steamed breads were prepared from five different starter cultures,marked as CK(control check,with no starters),Y(only yeast),YL(yeast+LAB),YA(yeast+AAB)and YLA(yeast+LAB+AAB),and their properties were determined.The results of sour dough properties showed that the YLA sourdough had the highest total titratable acid of 14.6 mL and the lowest pH of 3.87 compared with the other groups after fermentation to 8 h;and the YLA sourdough had the greatest elasticity and viscosity.The results of quality properties of steamed bread revealed that the L*value(88.40±0.09)of the YA steamed bread was significantly higher than those of the YLA and YL steamed breads;the YLA steamed bread had the highest specific volume and the highest sensory score of 89.6±3.31 in comparison to those of the other groups;the hardness and chewiness of YLA and YA steamed breads were significantly lower than those of the other groups.Volatile compounds in the steamed breads were also determined by SPME-GC-MS.A total of 42 flavor substances were detected,including 3 kinds of alcohols,8 kinds of aldehydes,7 kinds of ketones,2 kinds of acids,15 kinds of esters,1 furan,and 6 kinds of other types of compounds,mainly alkanes and esters,followed by alcohols and aldehydes.The YLA steamed bread was richer in esters,aldehydes,and acids than those from the other treatment groups.By contrast,alkanes and aldehydes were dominant in the Y and YL steamed breads.Therefore,the flavor and quality of the steamed bread made from the YLA sourdough could be improved obviously.These results could provide references for the application of AAB in dough fermentation and the improvement of new kinds of starters.
文摘The paper presents data about the antimicrobial activity of the autochthonous compound of taninic source Enoxil. The minimal inhibitory and bactericidal/fungicidal concentrations were established for some skin and wound infectious agents. It was established, based on Pseudomonas bacteria model, that the Enoxil compound suppress the activity of some important enzymes—a phenomenon that leads to the increase of bacterial sensibility to many tested antibiotics.