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Production of natural antimicrobial compound d ‐phenyllactic acid using L euconostoc mesenteroides ATCC 8293 whole cells involving highly active d ‐lactate dehydrogenase
Author(s) -
Li L.,
Shin S.Y.,
Lee K.W.,
Han N.S.
Publication year - 2014
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/lam.12293
Subject(s) - leuconostoc mesenteroides , leuconostoc , lactic acid , fermentation , antimicrobial , lactate dehydrogenase , biochemistry , food science , dehydrogenase , enzyme , chemistry , biology , bacteria , microbiology and biotechnology , lactobacillus , genetics
Phenyllactic acid (PLA) is an antimicrobial compound naturally synthesized in various fermented foods and its D‐form of PLA is known to be more active than the L‐isomer. In this study, Leuconostoc mesenteroides ATCC 8293 cells, elaborating d ‐lactate dehydrogenase ( d ‐ldh) were used to produce d ‐PLA from phenylpyruvic acid (PPA). When cultured in the presence of PPA (≤50 mmol l −1 ), growing cells produced a maximum yield of 35 mmol l −1 of d ‐PLA, and the yields were between 75·2 and 83·3%. Higher conversion yields were obtained at pH 6·0–7·0 when growing cells were used, while the optimum pH range was broader for resting cells. The time required for the complete conversion of PPA into PLA could be shortened to 3 h using resting cells. d ‐ldh, an enzyme encoded by the LEUM_1756 gene of Leuc. mesenteroides ATCC 8293, was found to be responsible for the conversion of PPA into PLA. The K m and k cat values of the enzyme for PPA were found to be 15·4 mmol l −1 and 5645 s −1 , respectively. The conditions required for the efficient production of d ‐PLA were optimized for both growing and resting cells of Leuc. mesenteroides , with special emphasis on achieving high stereoselectivity and conversion yield. Significance and Impact of the Study This is the first study on the production of d ‐phenyllactic acid, which is a natural antimicrobial compound, from phenylpyruvate using L euconostoc mesenteroides cells. The strain, ATCC 8293, that was used in the study, possesses high stereoselectivity and delivers a high yield. Therefore, it might be a promising candidate for use in large‐scale production facilities and in fermented foods.