BACKGROUND Probiotic Acetobacter pasteurianus is used to treat diabetes,but its specific hypoglycemic substances and mechanisms remain unclear.AIM To investigate the components for lipid metabolism of A.pasteurianus a...BACKGROUND Probiotic Acetobacter pasteurianus is used to treat diabetes,but its specific hypoglycemic substances and mechanisms remain unclear.AIM To investigate the components for lipid metabolism of A.pasteurianus and its hypoglycemic effects,providing a basis for its broader application.METHODS The lipid metabolism of A.pasteurianus under different growth conditions was analyzed using lipidomics.Neutral lipid staining in A.pasteurianus cells and the formation of lipid droplet-like structures were observed using a confocal laser scanning microscope.The neutral lipid components were also analyzed using thin layer chromato-graphy.A diabetic mouse model was established to evaluate the hypoglycemic effects of the main lipid components of A.pasteurianus and their role in repairing tissues such as the pancreas.RESULTS After comparing the effects of three culture media,namely,brain heart infusion(BHI)medium with 2%glucose,chromium-rich and zinc-rich medium,and mineral salt medium,A.pasteurianus grew well in BHI containing 2%glucose and produced the most lipids.A total of 583 lipid metabolic products was identified,with higher levels of coenzyme Q9(CoQ9),oleic acid(OA),and wax ester,but no triacylglycerol was observed.It was found that the components that affected lipid metabolism in A.pasteurianus were mainly CoQ9 and OA.They exhibited hypoglycemic effects comparable to metformin in diabetic mice,repaired damaged pancreatic tissues,and did not cause damage to the liver and spleen.CONCLUSION Under high-nutrient growth conditions,A.pasteurianus contains abundant lipid components,such as CoQ9 and OA,with good hypoglycemic effects.展开更多
Pyrroloquinoline quinone(PQQ)is believed to be a new B vitamin compound,and dietary PQQ has received more attention as a potential treatment for diseases including inflammatory injury and obesity.It widely exists in f...Pyrroloquinoline quinone(PQQ)is believed to be a new B vitamin compound,and dietary PQQ has received more attention as a potential treatment for diseases including inflammatory injury and obesity.It widely exists in foods related to acetic acid bacteria fermentation like fermented vinegars.To obtain a food-grade PQQ highyielding strain,clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated proteins(CRISPR/Cas)-based genome editing system was applied to genetically manipulate Acetobacter pasteurianus Ab3 for utilizing in industrial vinegar fermentation.Its PQQ biosynthetic genes were first characterized with conserved pqqA gene and pqqBCDE operon,and tldD gene instead of pqqF/G.Besides,our results revealed that pqqBCDE but not pqqA was the major limiting factor of improving PQQ production.Furthermore,endogenous promoters were screened from transcriptome data and evaluated their strength of improving PQQ production.The promoter P2690 showed the best efficiency and was selected to overexpress pqqBCDE operon.The engineered strain A.pasteurianus Ab3:P2690 produced 12.74μg/mL of PQQ,which was 9.1-fold higher than that of WT strain.The potential of PQQ production of the engineering strain A.pasteurianus Ab3:P2690 was further investigated by the semi-continuous fermentation in a 3 L fermentation tank.After 240 h of fermentation,the concentration of PQQ reached 41.96μg/mL.To our knowledge,this is the greatest PQQ yield reported so far using A.pasteurianus as a host strain.This study provides a practical approach to construct PQQ high-yielding A.pasteurianus strain that can be used in food industry and enhanced the health-promoting properties of vinegars.展开更多
L.litseifolius,a sweet-leafed primarily distributed in southern China,exhibits potential as a novel substrate for kombucha fermentation.This study developed a two-stage co-fermentation to enhance the flavor of L.litse...L.litseifolius,a sweet-leafed primarily distributed in southern China,exhibits potential as a novel substrate for kombucha fermentation.This study developed a two-stage co-fermentation to enhance the flavor of L.litseifolius kombucha,by using Lactobacillus plantarum,Acetobacter pasteurianus,and Kluyveromyces marxianus as co-starters.Co-fermentation significantly altered free amino acids(FAAs),volatile flavor compounds(VFCs),and organic acids(OAs),attenuating the pungent acetic acid odor and imparting a distinctive floral,fruity,and fatty aroma.High-throughput sequencing analysis revealed that Acetobacter pasteurianus maintained dominance throughout the fermentation.Correlation analysis and redundancy analysis(RDA)definitively confirmed the synergistic effects of bacteria and fungi on shaping the final flavor profile,particularly contributing to the formation of floral-fruity aroma,umami,and sourness.Furthermore,untargeted metabolomics identified 40 differential metabolites in triple-strain co-fermentation,including cis-4-coumaric acid,2-isopropylmalic acid,caffeic acid et al.KEGG pathway enrichment analysis mapped probable biosynthetic pathways for these compounds,particularly those involving FAAs(e.g.,alanine,aspartate)and OAs(e.g.,coumarate,succinate).This study provides insights into flavor formation mechanisms in L.litseifolius co-fermentation,offering a scientific basis for developing novel plant-based fermented beverages.展开更多
To investigate the quality variations of prune vinegar during fermentation,multivariate statistical analysis(MSA)was used in conjunction with high-performance liquid chromatography(HPLC)and gas chromatography-mass spe...To investigate the quality variations of prune vinegar during fermentation,multivariate statistical analysis(MSA)was used in conjunction with high-performance liquid chromatography(HPLC)and gas chromatography-mass spectrometry(GC-MS).The results showed that the pH decreased slightly,there was a rapid decline in sugar content,and a gradual increase in total acid content,which achieved stabilization at 3.68 g/100 mL.The content of organic acid increased,while the total phenol content decreased.The total flavonoid content did not change significantly.Furthermore,the antioxidant capacity initially decreased and then increased.Prune vinegar contains important phenolics such as rutin,resveratrol,salicylic acid,trans-ferulic acid,and(+)-catechin.In addition,the flavor of prune fruit vinegar underwent changes during the fermentation process.During the fermentation of fruit vinegar,large quantities of 2,3-butanediol,glacial acetic acid,nonanoic acid,ethyl acetate,ethyl heptanoate,ethyl caproate,and linalool were produced.These compounds give prune vinegar its distinctive fruity and floral aroma.This study provided a comprehensive framework for the efficient processing of prunes and a strategy for enhancing the quality characteristics of prune vinegar or other fermented products.展开更多
基金Supported by the Guangxi Science and Technology Major Projects,No.AA23073012the National Natural Science Foundation of China,No.32360035 and No.32060018.
文摘BACKGROUND Probiotic Acetobacter pasteurianus is used to treat diabetes,but its specific hypoglycemic substances and mechanisms remain unclear.AIM To investigate the components for lipid metabolism of A.pasteurianus and its hypoglycemic effects,providing a basis for its broader application.METHODS The lipid metabolism of A.pasteurianus under different growth conditions was analyzed using lipidomics.Neutral lipid staining in A.pasteurianus cells and the formation of lipid droplet-like structures were observed using a confocal laser scanning microscope.The neutral lipid components were also analyzed using thin layer chromato-graphy.A diabetic mouse model was established to evaluate the hypoglycemic effects of the main lipid components of A.pasteurianus and their role in repairing tissues such as the pancreas.RESULTS After comparing the effects of three culture media,namely,brain heart infusion(BHI)medium with 2%glucose,chromium-rich and zinc-rich medium,and mineral salt medium,A.pasteurianus grew well in BHI containing 2%glucose and produced the most lipids.A total of 583 lipid metabolic products was identified,with higher levels of coenzyme Q9(CoQ9),oleic acid(OA),and wax ester,but no triacylglycerol was observed.It was found that the components that affected lipid metabolism in A.pasteurianus were mainly CoQ9 and OA.They exhibited hypoglycemic effects comparable to metformin in diabetic mice,repaired damaged pancreatic tissues,and did not cause damage to the liver and spleen.CONCLUSION Under high-nutrient growth conditions,A.pasteurianus contains abundant lipid components,such as CoQ9 and OA,with good hypoglycemic effects.
基金supported by the Natural Science Foundation of Zhejiang Province[LY23C200003].
文摘Pyrroloquinoline quinone(PQQ)is believed to be a new B vitamin compound,and dietary PQQ has received more attention as a potential treatment for diseases including inflammatory injury and obesity.It widely exists in foods related to acetic acid bacteria fermentation like fermented vinegars.To obtain a food-grade PQQ highyielding strain,clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated proteins(CRISPR/Cas)-based genome editing system was applied to genetically manipulate Acetobacter pasteurianus Ab3 for utilizing in industrial vinegar fermentation.Its PQQ biosynthetic genes were first characterized with conserved pqqA gene and pqqBCDE operon,and tldD gene instead of pqqF/G.Besides,our results revealed that pqqBCDE but not pqqA was the major limiting factor of improving PQQ production.Furthermore,endogenous promoters were screened from transcriptome data and evaluated their strength of improving PQQ production.The promoter P2690 showed the best efficiency and was selected to overexpress pqqBCDE operon.The engineered strain A.pasteurianus Ab3:P2690 produced 12.74μg/mL of PQQ,which was 9.1-fold higher than that of WT strain.The potential of PQQ production of the engineering strain A.pasteurianus Ab3:P2690 was further investigated by the semi-continuous fermentation in a 3 L fermentation tank.After 240 h of fermentation,the concentration of PQQ reached 41.96μg/mL.To our knowledge,this is the greatest PQQ yield reported so far using A.pasteurianus as a host strain.This study provides a practical approach to construct PQQ high-yielding A.pasteurianus strain that can be used in food industry and enhanced the health-promoting properties of vinegars.
基金supported by the Science and Technology SMES Innovation Ability Improvement Project of Shandong Province(Project No.2023TSGC0980)the Key Research and Development Program of Changzhou(Project No.CE20222005).
文摘L.litseifolius,a sweet-leafed primarily distributed in southern China,exhibits potential as a novel substrate for kombucha fermentation.This study developed a two-stage co-fermentation to enhance the flavor of L.litseifolius kombucha,by using Lactobacillus plantarum,Acetobacter pasteurianus,and Kluyveromyces marxianus as co-starters.Co-fermentation significantly altered free amino acids(FAAs),volatile flavor compounds(VFCs),and organic acids(OAs),attenuating the pungent acetic acid odor and imparting a distinctive floral,fruity,and fatty aroma.High-throughput sequencing analysis revealed that Acetobacter pasteurianus maintained dominance throughout the fermentation.Correlation analysis and redundancy analysis(RDA)definitively confirmed the synergistic effects of bacteria and fungi on shaping the final flavor profile,particularly contributing to the formation of floral-fruity aroma,umami,and sourness.Furthermore,untargeted metabolomics identified 40 differential metabolites in triple-strain co-fermentation,including cis-4-coumaric acid,2-isopropylmalic acid,caffeic acid et al.KEGG pathway enrichment analysis mapped probable biosynthetic pathways for these compounds,particularly those involving FAAs(e.g.,alanine,aspartate)and OAs(e.g.,coumarate,succinate).This study provides insights into flavor formation mechanisms in L.litseifolius co-fermentation,offering a scientific basis for developing novel plant-based fermented beverages.
基金financially supported by the Support Programme for Innovation and Development of Key Industries in Southern Border in Xinjiang Production and Construction Corps,China(No.2022DB007-2).
文摘To investigate the quality variations of prune vinegar during fermentation,multivariate statistical analysis(MSA)was used in conjunction with high-performance liquid chromatography(HPLC)and gas chromatography-mass spectrometry(GC-MS).The results showed that the pH decreased slightly,there was a rapid decline in sugar content,and a gradual increase in total acid content,which achieved stabilization at 3.68 g/100 mL.The content of organic acid increased,while the total phenol content decreased.The total flavonoid content did not change significantly.Furthermore,the antioxidant capacity initially decreased and then increased.Prune vinegar contains important phenolics such as rutin,resveratrol,salicylic acid,trans-ferulic acid,and(+)-catechin.In addition,the flavor of prune fruit vinegar underwent changes during the fermentation process.During the fermentation of fruit vinegar,large quantities of 2,3-butanediol,glacial acetic acid,nonanoic acid,ethyl acetate,ethyl heptanoate,ethyl caproate,and linalool were produced.These compounds give prune vinegar its distinctive fruity and floral aroma.This study provided a comprehensive framework for the efficient processing of prunes and a strategy for enhancing the quality characteristics of prune vinegar or other fermented products.
