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Deciphering the d-/l-lactate-producing microbiota and manipulating their accumulation during solid-state fermentation of cereal vinegar
- Chai, Li-Juan, Shen, Mi-Na, Sun, Jia, Deng, Yong-Jian, Lu, Zhen-Ming, Zhang, Xiao-Juan, Shi, Jin-Song, Xu, Zheng-Hong
- Food microbiology 2020 v.92 pp. 103559
- Acetobacter pasteurianus, Lactobacillus casei, Lactobacillus helveticus, Lactobacillus plantarum, Lactobacillus reuteri, acetic acid, bioaugmentation, flavor, genes, lactate dehydrogenase, lactic acid, microorganisms, niches, sequence analysis, solid state fermentation, vinegars
- Symphony orchestra of multi-microorganisms characterizes the solid-state acetic acid fermentation process of Chinese cereal vinegars. Lactate is the predominant non-volatile acid and plays indispensable roles in flavor formation. This study investigated the microbial consortia driving the metabolism of D-/l-lactate during fermentation. Sequencing analysis based on D-/l-lactate dehydrogenase genes demonstrated that Lactobacillus (relative abundance: > 95%) dominated the production of both d-lactate and l-lactate, showing species-specific features between the two types. Lactobacillus helveticus (>65%) and L. reuteri (~80%) respectively dominated l- and d-lactate-producing communities. D-/l-lactate production and utilization capabilities of eight predominant Lactobacillus strains were determined by culture-dependent approach. Subsequently, D-/l-lactate producer L. plantarum M10-1 (d:l ≈ 1:1), l-lactate producer L. casei 21M3-1 (D:L ≈ 0.2:9.8) and D-/l-lactate utilizer Acetobacter pasteurianus G3-2 were selected to modulate the metabolic flux of D-/l-lactate of microbial consortia. The production ratio of D-/l-lactate was correspondingly shifted coupling with microbial consortia changes. Bioaugmentation with L.casei 21M3-1 merely enhanced l-lactate production, displaying ~4-fold elevation at the end of fermentation. Addition of L.plantarum M10-1 twice increased both D- and l-lactate production, while A. pasteurianus G3-2 decreased the content of D-/l-isomer. Our results provided an alternative strategy to specifically manipulate the metabolic flux within microbial consortia of certain ecological niches.