Improved triglyceride transesterification by circular permuted Candida antarctica lipase B.

Area of Science:

• Biocatalysis and Enzyme Engineering
• Industrial Biotechnology
• Lipase Applications

Background:

• Lipases are crucial biocatalysts with broad industrial applications, notably in biodiesel production via enzyme-catalyzed transesterification.
• Candida antarctica lipase B (CALB) is a well-established lipase, but engineered variants can offer improved performance characteristics.

Purpose of the Study:

• To evaluate the catalytic performance of cp283, a circularly permuted variant of CALB.
• To compare the activity of cp283 against wild-type CALB using various ester and triglyceride substrates.

Main Methods:

• Enzyme activity assays were conducted using a series of esters and triglycerides as substrates.
• Transesterification and interesterification reactions were performed with 1-butanol and ethyl acetate as acyl acceptors.
• Comparative analysis of catalytic rates between wild-type CALB and the engineered cp283 variant.

Main Results:

• The engineered lipase cp283 exhibited consistently higher catalytic activity, ranging from 2.6- to 9-fold greater than wild-type CALB.
• Enhanced activity was observed for both transesterification and interesterification reactions across different substrates.
• Differences in reaction rates suggest altered rate-determining steps in the catalytic cycle due to circular permutation.

Conclusions:

• Circular permutation engineering significantly enhances the catalytic efficiency of Candida antarctica lipase B (CALB).
• The cp283 variant shows superior performance for transesterification and interesterification, making it a promising biocatalyst for industrial processes.
• The improved activity is likely attributed to modifications in the enzyme's catalytic cycle mechanism resulting from circular permutation.