Characterization reveals a putative Epoxide hydrolase from Yarrowia lipolytica with the ability to convert rac-1,2-epoxyhexane to (R)-diol.

Microbial epoxide hydrolases (EHs) find relevance in the pharmaceutical and biotechnology industries. The gene (YALI0_A01441g) encoding an epoxide hydrolase (Yleh) from a tropical marine yeast Yarrowia lipolytica NCIM 3589 was characterized. In-silico analysis suggested that the Yleh gene belonged to α/β-hydrolase fold superfamily with two characteristic motifs, HGFP and GYTRS. Phylogenetic analysis showed that Yleh was far removed from microbial EHs. The cloned, expressed protein was a ∼42 kDa enzyme exhibiting EH activity of 4.07 ± 2.19 μmol min−1 mg−1 protein with 1,2-epoxyhexane. It was active over a wide range of temperature (20–50 °C) and pH (4−10) with optimal activity at 30 °C and pH 8.0. For 1,2-epoxyhexane, Km, Vmax and kcat/Km values were 2.14 ± 0.25 mM, 0.025 ± 0.002 μmol min−1 and 8.48 ± 1.71 mM−1 s−1 respectively. EH activity was strongly inhibited by Ag2+, Hg2+, Zn2+, whereas Cu3+ and Cu2+ enhanced it. Ligand binding studies indicated a good affinity (Ka=0.036 mM) between substrate and Yleh. Studies with purified enzyme and permeabilized cells on 1,2-epoxyhexane (2.5–15 mM) suggest specificity towards (R)− 1,2-epoxyhexane with the production of (R)− 1,2-hexanediol with ∼70 % and 80 % conversion, respectively. Thus, Yleh from Y. lipolytica might serve as a promising candidate to meet the process for conversion of epoxides to industrially relevant diols.