Open AccessA cold‐adapted leucine dehydrogenase from marine bacterium Alcanivorax dieselolei : Characterization and l ‐tert ‐leucine production
Author(s) -
Jiang Wei,
Sun Dongfang,
Lu Jixue,
Wang Yali,
Wang Shizhen,
Zhang Yonghui,
Fang Baishan
Publication year - 2016
Publication title -
engineering in life sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.547
H-Index - 57
eISSN - 1618-2863
pISSN - 1618-0240
DOI - 10.1002/elsc.201500092
Subject(s) - leucine , biochemistry , bioconversion , bacillus cereus , dehydrogenase , enzyme , biology , bacteria , amino acid , chemistry , fermentation , genetics
l ‐ tert ‐leucine, an intermediate in the synthesis of several chiral drugs, is mainly produced by bioconversion, in which leucine dehydrogenase (LeuDH) is the key enzyme. A novel leudh was obtained from the marine bacterium Alcanivorax dieselolei B‐5(T) by PCR. The gene encoded a novel cold‐adapted LeuDH that showed low similarity (less than 50%) to any known proteins; the highest similarity (42.6%) was found for LeuDH from Bacillus cereus . The cold‐adapted LeuDH showed optimal activity at 30℃ and pH 6.5, and was identified to be extremely cold‐adaptive, retaining over 90% activity in the temperature range of 0–37℃. The enzyme exhibited better stability in weak alkali environment (pH 6.0–8.5) than Thermoactinomyces intermedius LeuDH. The best substrate concentration was established, and LeuDH conversion rate in catalyzing trimethylpyruvic acid to l ‐ tert ‐leucine was 54.6%. The cold activity and its ability to produce l ‐ tert ‐leucine with excellent performance of enantiomers of choice make it a promising biocatalyst for industrial application under extreme conditions.