earticle

영어

Polylactic acid (PLA) is considered to be one of the most promising biosource-derived polymer replacing current petrochemical ones. Optically pure lactic acid is favorable as a feedstock of polymer since even the presence of small amounts of the other isomer in PLA polymerization highly affects the properties of polymer. The fermentative production of lactic acid leads to optically pure isomer of lactic acid compared to the racemic mixtures of L and D isomers from chemical synthesis. The lactic acid fermentation is well documented in the literature, but reports on the optical purity of lactic acid during the fermentation are limited. In this study, the fermentation characteristics of L. paracasei KM2, ldhD knock-out cell, were compared with those of Lactobacillus paracasei KCTC 3510. In batch cultures and fed-batch cultures, the optical purity of produced lactic acid by L. paracasei KM2 was improved up to 99.8% compared to 97% by KCTC 3510. Fed-batch culture gave higher productivity while keeping the optical purity of lactic acid.