Efficient Production of Optically Pure d -Lactic Acid from Raw Corn Starch by Using a Genetically Modified l -Lactate Dehydrogenase Gene-Deficient and α-Amylase-Secreting Lactobacillus plantarum Strain

作者：Kenji Okano, Qiao Zhang, Satoru Shinkawa, Shogo Yoshida, Tsutomu Tanaka, Hideki Fukuda, Akihiko Kondo · 发表于：Applied and Environmental Microbiology · 年份：2008 · DOI：10.1128/aem.01514-08 · 被引用次数：110 · 研究领域：Probiotics and Fermented Foods、Microbial Metabolites in Food Biotechnology、Enzyme Production and Characterization

In order to achieve direct and efficient fermentation of optically pure D-lactic acid from raw corn starch, we constructed L-lactate dehydrogenase gene (ldhL1)-deficient Lactobacillus plantarum and introduced a plasmid encoding Streptococcus bovis 148 alpha-amylase (AmyA). The resulting strain produced only D-lactic acid from glucose and successfully expressed amyA. With the aid of secreting AmyA, direct D-lactic acid fermentation from raw corn starch was accomplished. After 48 h of fermentation, 73.2 g/liter of lactic acid was produced with a high yield (0.85 g per g of consumed sugar) and an optical purity of 99.6%. Moreover, a strain replacing the ldhL1 gene with an amyA-secreting expression cassette was constructed. Using this strain, direct D-lactic acid fermentation from raw corn starch was accomplished in the absence of selective pressure by antibiotics. This is the first report of direct D-lactic acid fermentation from raw starch.