Open AccessRelative catalytic efficiencies and transcript levels of three d ‐ and two l ‐lactate dehydrogenases for optically pure d ‐lactate production in Sporolactobacillus inulinus
Author(s) -
Wu Bin,
Yu Qi,
Zheng Shan,
Pedroso Marcelo Monteiro,
Guddat Luke W.,
He Bingfang,
Schenk Gerhard
Publication year - 2019
Publication title -
microbiologyopen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.881
H-Index - 36
ISSN - 2045-8827
DOI - 10.1002/mbo3.704
Subject(s) - lactate dehydrogenase , ethyl lactate , lactate dehydrogenase a , chemistry , biochemistry , catalysis , escherichia coli , enzyme , nuclear chemistry , gene
As the optical purity of the lactate monomer is pivotal for polymerization, the production of optically pure d ‐lactate is of significant importance. Sporolactobacillus inulinus YBS 1‐5 is a superior optically pure d ‐lactate‐producing bacterium. However, little is known about the relationship between lactate dehydrogenases in S. inulinus YBS 1‐5 and the optical purity of d ‐lactate. Three potential d ‐lactate dehydrogenase (D‐ LDH 1‐3)‐ and two putative l ‐lactate dehydrogenase (L‐ LDH 1‐2)‐encoding genes were cloned from the YBS 1‐5 strain and expressed in Escherichia coli D‐ LDH 1 exhibited the highest catalytic efficiency toward pyruvate, whereas two L‐ LDH s showed low catalytic efficiency. Different neutralizers significantly affected the optical purity of d ‐lactate produced by strain YBS 1‐5 as well as the transcription levels of ldh Ds and ldh Ls. The high catalytic efficiency of D‐ LDH 1 and elevated ldh D1 mRNA levels suggest that this enzyme is essential for d ‐lactate synthesis in S. inulinus YBS 1‐5. The correlation between the optical purity of d ‐lactate and transcription levels of ldh L1 in the case of different neutralizers indicate that ldh L1 is a key factor affecting the optical purity of d ‐lactate in S. inulinus YBS 1‐5.