Preparation Of (S)-1-Phenyl-1,2-Ethanediol By Enantioselective Hydrolysis Of Dicarboxyester With Recombinant Bacillus Subtilis Esterase

1-Phenyl-1,2-ethanediol (PED) is a very important building block in chemical and pharmaceutical industries. As it has two hydroxyl groups, selective protection of one hydroxyl to prepare optically pure PED is usually necessary in chemical methods. So biopreparation of optically pure PED becomes more and more attractive. Whole cells of recombinant E. coli overexpressing Bacillus subtilis esterase (BSE) were used as biocatalyst for enantioselective hydrolysis of 1-phenyl-1,2-ethanediol diacetate (PEDDA) to prepare (S)-PED. It exhibited high hydrolytic activity and enantioselectivity. The best catalytic enantioselectivity (E=176) was obtained for PEDDA of dicarboxyesters with different acyl chains (e.g., acetyl, n-butyl, n-hexyl). Various reaction conditions were examined for optimizing the enantioselective hydrolysis. Under the optimal reaction conditions, enzymatic resolution of 100 mM (R,S)-PEDDA resulted in 49% yield within 1 h affording (S)-PED with 96% ee. A 150 ml scale reaction was performed, affording (S)-PED in 49.0% yield and 95% ee. After recrystallization in CHCl3, optical purity of the product was improved to> 99% ee, with a total yield of 45%. These results imply that this recombinant esterase is a potentially promising biocatalyst for bioproduction of (S)-PED.