Stereoselectivities of microbial epoxide hydrolases

Area of Science:

• Biocatalysis
• Enzymology
• Organic Chemistry

Background:

• Epoxide hydrolases (EHs) are crucial biocatalysts for asymmetric epoxide hydrolysis.
• These enzymes enable both kinetic resolution and enantioconvergent processes for producing chiral diols.
• Microbial EHs offer a sustainable and efficient alternative to traditional chemical methods.

Purpose of the Study:

• To review and correlate the enantioselectivities of bacterial and fungal epoxide hydrolases with substrate structure.
• To identify optimal microbial sources for specific epoxide types in preparative-scale synthesis.
• To highlight the potential of EHs in asymmetric synthesis of vicinal diols.

Main Methods:

• Literature review of studies on microbial epoxide hydrolases.
• Analysis of reported enantioselectivities for various substrate classes.
• Correlation of enzyme performance with microbial origin (yeast, fungi, bacteria) and substrate substitution patterns.

Main Results:

• Red yeasts (Rhodotorula, Rhodosporidium) show high enantioselectivity for monosubstituted epoxides.
• Fungal EHs (Aspergillus, Beauveria) are optimal for styrene oxide-type substrates.
• Bacterial EHs (Actinomycetes: Rhodococcus, Nocardia) excel with 2,2- and 2,3-disubstituted epoxides.

Conclusions:

• Microbial epoxide hydrolases exhibit substrate-specific enantioselectivity.
• The choice of microbial source is critical for achieving high enantiomeric excess in epoxide hydrolysis.
• These findings guide the selection of appropriate biocatalysts for efficient asymmetric synthesis of epoxides.