A cold-adapted leucine dehydrogenase from marine bacterium Alcanivorax dieselolei: Characterization and l-tert-leucine production

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• 作者：Wei Jiang ; Dongfang Sun ; Jixue Lu ; Yali Wang ; Shizhen Wang ; Yonghui Zhang and Baishan Fang
• 关键词：Alcanivorax dieselolei ; Cold adaptation ; Extreme environments ; LeuDH ; l-tert-leucine enzymatic production
• 刊名：Engineering in Life Sciences
• 出版年：2016
• 出版时间：April 2016
• 年：2016
• 卷：16
• 期：3
• 页码：283-289
• 全文大小：614K
• ISSN：1618-2863

文摘

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.