Main content area

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.