Combined use of single molecule real-time DNA sequencing technology and culture-dependent methods to analyze the functional microorganisms in inoculated raw wheat Qu

• Published in: Food research international 2020-06, Vol.132, p.109062-109062, Article 109062
• Main Authors: Liu, Shuangping, Hu, Jian, Xu, Yuezheng, Xue, Jingbo, Zhou, Jiandi, Han, Xiao, Ji, Zhongwei, Mao, Jian
• Format: Article
• Language: English
• Subjects: Bacteria - classification; Bacteria - enzymology; Bacteria - isolation & purification; China; Culture Techniques - methods; Enzymes - analysis; Fermentation; Flavoring Agents; Functional microorganism; Fungi - classification; Fungi - enzymology; Fungi - isolation & purification; Huangjiu (Chinese rice wine); Microbiota; Microbiota - genetics; Mycobiome - genetics; Sequence Analysis, DNA - methods; Single molecule real-time DNA sequencing technology; Triticum - microbiology; Volatile Organic Compounds - analysis; Wheat Qu; Wine
• ISSN: 0963-9969; 1873-7145
• DOI: 10.1016/j.foodres.2020.109062

[Display omitted] •Inoculated raw wheat Qu (IRWQ) is a perfect improvement of traditional wheat Qu.•IRWQ maintained the microbial diversity and enhanced hydrolytic enzyme activities.•IRWQ microbiota is firstly disclosed by single molecule real-time DNA sequencing.•The functional microorganisms in IRWQ was firstly analyzied.•Mould, yeast and bacteria contributed different aspects to IRWQ characters. Inoculated raw wheat Qu (IRWQ), which can be produced with high efficiency and low cost while maintaining stable quality, is a new Qu that has been applied to Huangjiu brewing. In this study, single molecule real-time DNA sequencing technology and culture-dependent methods were combined for the first time to study the microbiota and the function of the principle microorganisms in IRWQ. The glucoamylase, amylase and protease contents of IRWQ were 1.17, 1.55 and 2.87-times greater, respectively, than those of traditional wheat Qu. Like traditional wheat Qu, the main volatile flavor compounds in IRWQ were alcohols; however, the esters content was much higher and the acids content was much lower. Single molecule real-time DNA sequencing technology identified 18 fungal species and 59 bacterial species in IRWQ. Then, 30 species were isolated by culture-dependent methods. These species represented about 80% of the total fungal microbiota and 35% of the total bacteria microbiota. Molds were the main contributors of glucoamylase, amylase and protease activities. Aspergillus flavus had the highest glucoamylase and protease activity. Bacillus subtilis and Bacillus amyloliquefaciens also produced high hydrolytic enzyme activities. Saccharomyces cerevisiae produced the largest amounts of aromatics compounds, alcohols, esters and acids. Aldehydes and ketones are mainly produced by molds.