Industrial adaptability selection for a novel ω-transaminase

Abstract:

ω-transaminase (ω-TA) is the most promising biocatalyst for chiral amine synthesis. However, most wild-type ω-TAs cannot be applied in industry directly due to their low stability and unfavorable reaction equilibrium. In order to discover a novel ω-TA for industrial application, we designed a procedure of adaptive selection, including the screening of substrates, protein sequences and clones, enzyme activity, and product conversion and characterization, as well as trouble-shooting of each step. Through this procedure, we screened a novel ω-TA, ATA-W12 of Caulobacter sp. from a soil metagenome. The strain could convert 20 mmol/L 1-Boc-3-pyrrolidinone and 20 mmol/L 1-Boc-3-piperidone with 85.84% and 67.42% conversion rate, respectively, in a 1-mL scale with isopropylamine (IPA) as amine donor. ATA-W12 maintained 100% activity at 40 °C for 168 h, and its optimal reaction condition is at pH 8.5 and 40 °C. These excellent properties benefit the application of IPA as an ideal amino donor in industry. We scaled up the production of (S)-(+)-1-boc-3-aminopiperidine up to 50 mL (100 g/L) scale with this novel biocatalyst for its further industrial application.

Key words:chiral amine synthesis, ω-transaminase, isopropylamine, adaptive selection