Biocatalytic resolution of glycidyl phenyl ether using a novel epoxide hydrolase from a marine bacterium, Rhodobacterales bacterium HTCC2654

Abstract

As a continuous effort of developing highly enantioselective epoxide hydrolase from marine microorganisms, it was found that Maritimibacter alkaliphilus KCCM 42376 [corrected] was highly enantioselective toward racemic glycidyl phenyl ether (GPE). An open reading frame (ORF) encoding a putative epoxide hydrolase (EHase) was cloned from the genome of Maritimibacter alkaliphilus KCCM 42376 [corrected], followed by expression and purification in Escherichia coli. The purified EHase (REH) hydrolyzed (S)-GPE preferentially over (R)-GPE. Enantiopure (R)-GPE from kinetic resolution of 29.2 mM racemic GPE using the purified REH could be obtained with enantiopurity of more than 99.9% enantiomeric excess (ee) and 38.4% yield (theoretical, 50%) within 20 min (enantiomeric ratio (E-value): 38.4). The enantioselective activity of REH toward GPE was also confirmed by the analysis of the vicinal diol, 3-phenoxy-1,2-propanediol. To our knowledge, this study demonstrates the highest enantioselective resolution of racemic GPE using a purified biocatalyst among the known native EHases.