Enantioselective transesterification using immobilized Aspergillus oryzae overexpressing lipase

Area of Science:

• Biotechnology
• Enzyme Engineering
• Organic Chemistry

Background:

• Chiral compounds are crucial in pharmaceuticals and fine chemicals.
• Efficient methods for optical resolution are essential for producing enantiomerically pure substances.
• Aspergillus oryzae is a well-established host for enzyme production.

Purpose of the Study:

• To construct a recombinant Aspergillus oryzae strain overexpressing lipase.
• To investigate the application of this strain for the optical resolution of chiral compounds.
• To develop a robust whole-cell biocatalyst for enantioselective synthesis.

Main Methods:

• Gene manipulation to overexpress the tglA lipase gene in Aspergillus oryzae.
• Cloning and reintroduction of the tglA gene with and without a secretion-signal sequence.
• Immobilization of the recombinant strain within biomass-support particles.
• Use of the immobilized whole-cell biocatalyst for enantioselective esterification.

Main Results:

• The recombinant strain overexpressing lipase with a secretion-signal sequence showed high activity.
• Selective synthesis of (R)-1-phenylethyl acetate from (RS)-1-phenylethanol and vinyl acetate.
• Achieved approximately 90% yield and 95% enantiomeric excess (%ee) for (R)-1-phenylethyl acetate.
• The biocatalyst maintained activity over 25 batch-reaction cycles.

Conclusions:

• The engineered Aspergillus oryzae strain is an effective whole-cell biocatalyst for optical resolution.
• The developed biocatalyst offers a stable and efficient method for producing enantiomerically pure (R)-1-phenylethyl acetate.
• This approach holds promise for industrial applications in chiral compound synthesis.