The quality and aroma of strong-flavor Baijiu are mainly dependent on Daqu,pit mud(PM),and the interaction of both.However,little is known about how their combination patterns affect the microbiome and metabolome of Z...The quality and aroma of strong-flavor Baijiu are mainly dependent on Daqu,pit mud(PM),and the interaction of both.However,little is known about how their combination patterns affect the microbiome and metabolome of Zaopei,especially the metabolic function of rare taxa.Here,an experiment on industrial size was designed to assess the effects of 6 combinations(3 kinds of Daqu×2 kinds of PM)on the composition and assembly of different taxa,as well as the flavor profile.The results showed that Zaopei's microbiota was composed of a few abundant taxa and enormous rare taxa,and rare bacterial and abundant fungal subcommunities were significantly affected by combination patterns.The assembly processes of abundant/rare taxa and bacterial/fungal communities were distinct,and environmental changes mediated the balance between stochastic and deterministic processes in rare bacteria assembly.Furthermore,specific combination patterns improved the flavor quality of Zaopei by enhancing the interspecies interaction,which was closely related to rare taxa,especially rare bacteria.These findings highlighted that rare bacteria might be the keystone in involving community interaction and maintaining metabolic function,which provided a scientific foundation for better understanding and regulating the brewing microbiota from the viewpoint of microbial ecology.展开更多
Daqu is the fermenting starter in Chinese Baijiu brewing,contributing functional microorganisms,enzymes and flavor substances to the grain fermentation.Traditional daqu is produced in open environment where environmen...Daqu is the fermenting starter in Chinese Baijiu brewing,contributing functional microorganisms,enzymes and flavor substances to the grain fermentation.Traditional daqu is produced in open environment where environmental factors and microbiota are critical to daqu and Baijiu quality.Mechanization is the direction of Baijiu production development.In this study,we investigated the mechanism of the effect of mechanized environment and manufacturing process on daqu production.Many functional microorganisms(e.g.Acetobacter,lactic acid bacteria and yeast)were distributed in the process environment,including indoor air,tube and equipment surfaces,which contributed to the initial bacterial/fungal composition in daqu(71.62%/28.47%)along with mature daqu powder(21.1%/61.65%).Our results also showed daqu microbiota formation was influenced by both stochastic and deterministic processes.The initial microorganisms produced large amounts of organic acids(19.24 g/kg)and bioheat(58.3◦C)during early fermentation stage,leading to a rapid temperature rise and water loss under the stacking process.Mature daqu powder mainly provided thermophilic microorganisms for fermentation stages during and after temperature rise,including Thermoactinomyces,Thermoascus,Thermomyces,Rhizomucor and Rhizopus,which produced enzymes and amino nitrogen for Baijiu fermentation,also ensuring stable microbiota among process batches.This work revealed the origin of the microbial community of strong-flavor daqu and showed that ecological environment suitable for daqu fermentation was created during the long-term continuous production process by adding mature daqu powder during daqu brick making and sprinkling it in the workshop,by which product quality was guaranteed.展开更多
A yeast strain had been isolated by dilution-plate from the Daqu samples in our study. The strain was identified as a strain of Rhodotorula aurantiaca through observation of its morphological features, micromorphologi...A yeast strain had been isolated by dilution-plate from the Daqu samples in our study. The strain was identified as a strain of Rhodotorula aurantiaca through observation of its morphological features, micromorphological observation and biolog identification system.展开更多
Abstract： Daqu distiller＇s grains were co-fermented as raw materials by Trichoderma.koningii and Trichosporon cutaneum to produce microbial oils, which can provide raw materials for bio-diesel development. The singl...Abstract： Daqu distiller＇s grains were co-fermented as raw materials by Trichoderma.koningii and Trichosporon cutaneum to produce microbial oils, which can provide raw materials for bio-diesel development. The single factor tests were used to investigate the effects of ratio of strains, inoculum size, culture temperature and culture time on the production of microbial oils. The best processing conditions were obtained by orthogonal test through measuring the content of microbial oils in product. The result shows that the microbial oils content of the co-fermented product under the ratio of Trichoderma.koningii to Trichosporon cutaneum of 1：1, the inoculum size of strains of 11% at 28 ℃ for 6 d is 7.15 g/L. It is shown that the production of microbial oils co-fermented by Trichoderma.koningii and Trichosporon cutaneum with Daqu distiller＇s grains is possible. The research provides a new idea for the reuse of Daqu distiller＇s grains and also provides a new way for the development of microbial oils.展开更多
基金supported by the Cooperation Project of Luzhou Laojiao Co.,Ltd.Sichuan University (21H0997)。
文摘The quality and aroma of strong-flavor Baijiu are mainly dependent on Daqu,pit mud(PM),and the interaction of both.However,little is known about how their combination patterns affect the microbiome and metabolome of Zaopei,especially the metabolic function of rare taxa.Here,an experiment on industrial size was designed to assess the effects of 6 combinations(3 kinds of Daqu×2 kinds of PM)on the composition and assembly of different taxa,as well as the flavor profile.The results showed that Zaopei's microbiota was composed of a few abundant taxa and enormous rare taxa,and rare bacterial and abundant fungal subcommunities were significantly affected by combination patterns.The assembly processes of abundant/rare taxa and bacterial/fungal communities were distinct,and environmental changes mediated the balance between stochastic and deterministic processes in rare bacteria assembly.Furthermore,specific combination patterns improved the flavor quality of Zaopei by enhancing the interspecies interaction,which was closely related to rare taxa,especially rare bacteria.These findings highlighted that rare bacteria might be the keystone in involving community interaction and maintaining metabolic function,which provided a scientific foundation for better understanding and regulating the brewing microbiota from the viewpoint of microbial ecology.
基金This work was financially supported by the National Natural Science Foundation of China(22138004)the first phase of the connotation construction of the 14th Five-Year Plan of Tibetan medicine(2021ZYYGH008)Sichuan post-doctoral program.
文摘Daqu is the fermenting starter in Chinese Baijiu brewing,contributing functional microorganisms,enzymes and flavor substances to the grain fermentation.Traditional daqu is produced in open environment where environmental factors and microbiota are critical to daqu and Baijiu quality.Mechanization is the direction of Baijiu production development.In this study,we investigated the mechanism of the effect of mechanized environment and manufacturing process on daqu production.Many functional microorganisms(e.g.Acetobacter,lactic acid bacteria and yeast)were distributed in the process environment,including indoor air,tube and equipment surfaces,which contributed to the initial bacterial/fungal composition in daqu(71.62%/28.47%)along with mature daqu powder(21.1%/61.65%).Our results also showed daqu microbiota formation was influenced by both stochastic and deterministic processes.The initial microorganisms produced large amounts of organic acids(19.24 g/kg)and bioheat(58.3◦C)during early fermentation stage,leading to a rapid temperature rise and water loss under the stacking process.Mature daqu powder mainly provided thermophilic microorganisms for fermentation stages during and after temperature rise,including Thermoactinomyces,Thermoascus,Thermomyces,Rhizomucor and Rhizopus,which produced enzymes and amino nitrogen for Baijiu fermentation,also ensuring stable microbiota among process batches.This work revealed the origin of the microbial community of strong-flavor daqu and showed that ecological environment suitable for daqu fermentation was created during the long-term continuous production process by adding mature daqu powder during daqu brick making and sprinkling it in the workshop,by which product quality was guaranteed.
文摘A yeast strain had been isolated by dilution-plate from the Daqu samples in our study. The strain was identified as a strain of Rhodotorula aurantiaca through observation of its morphological features, micromorphological observation and biolog identification system.
基金Project(10A110) supported by Hunan Provincial Education Department of ChinaProject(2010JT4055) supported by Hunan Provincial Science & Technology Department of China
文摘Abstract： Daqu distiller＇s grains were co-fermented as raw materials by Trichoderma.koningii and Trichosporon cutaneum to produce microbial oils, which can provide raw materials for bio-diesel development. The single factor tests were used to investigate the effects of ratio of strains, inoculum size, culture temperature and culture time on the production of microbial oils. The best processing conditions were obtained by orthogonal test through measuring the content of microbial oils in product. The result shows that the microbial oils content of the co-fermented product under the ratio of Trichoderma.koningii to Trichosporon cutaneum of 1：1, the inoculum size of strains of 11% at 28 ℃ for 6 d is 7.15 g/L. It is shown that the production of microbial oils co-fermented by Trichoderma.koningii and Trichosporon cutaneum with Daqu distiller＇s grains is possible. The research provides a new idea for the reuse of Daqu distiller＇s grains and also provides a new way for the development of microbial oils.
