Preparation of d-α-aminolactams by l-enantioselective degradation of α-aminolactam mediated by Mesorhizobium sp. L88

By the screening of microorganisms that can assimilate α-amino-ε-caprolactam (ACL) as a sole source of carbon and nitrogen from 115 soil samples, two microorganisms that can hydrolyze ACL l-enantioselectively and degrade further have been isolated and identified as Mesorhizobium sp. L88 and Aneurinibacillus migulanus L168. The culture and reaction conditions of Mesorhizobium sp. L88 were optimized to apply the intact cells to the preparation of enantiomerically pure d-α-aminolactams. Under the optimized conditions, d-α-aminolactams with a five- to an eight-membered ring were prepared with an enantiomeric excess of >99.8%. Ring-opened α-amino-N'-alkylamides, lysine amide, ornithine amide, ε-caprolactam, and δ-valerolactam were not accepted as substrates.