Process Biochemistry, Vol.48, No.11, 1674-1678, 2013
Asymmetric biocatalysis of S-3-amino-3-phenylpropionic acid with new isolated Methylobacterium Y1-6
beta-amino acids are widely used in drug research, and S-3-amino-3-phenylpropionic acid (S-APA) is an important pharmaceutical intermediate of S-dapoxetine, which has been approved for the treatment of premature ejaculation. Chiral catalysis is an excellent method for the preparation of enantiopure compounds. In this study, we used (+/-)-ethyl-3-amino-3-phenylpropanoate (EAP) as the sole carbon source. Three hundred thirty one microorganisms were isolated from 30 soil samples, and 17 strains could produce S-APA. After three rounds of cultivation and identification, the strain Y1-6 exhibiting the highest enantioselective activity of S-APA was identified as Methylobacterium oryzae. The optimal medium composition contained methanol (2.5 g/L), 1,2-propanediol (7.5 g/L), soluble starch (2.5 g/L), and peptone.(10 g/L); it was shaken at 220 rpm for 4-5 days at 30 degrees C. The optimum condition for biotransformation of EAP involved cultivation at 37 degrees C for 48 h with 120 mg of wet cells and 0.64 mg of EAP in 1 ml of transfer solution. Under this condition, substrate ee was 92.1% and yield was 48.6%. We then attempted to use Methylobacterium Y1-6 to catalyze the hydrolytic reaction with substrates containing 3-amino-3-phenylpropanoate ester, N-substituted-1 beta-ethyl-3-amino-3-phenyl-propanoate, and gamma-lactam. It was found that 5 compounds with ester bonds could be stereoselectively hydrolyzed to S-acid, and 2 compounds with gamma-lactam bonds could be stereoselectively hydrolyzed to (-)-gamma-lactam. (C) 2013 Elsevier Ltd. All rights reserved.
Keywords:Biocatalysis;Chiral separation;Methylobacterium sp.;S-3-amino-3-phenylpropanoate ester;Strain screening