Crosslinking of enzyme coaggregate with polyethyleneimine: A simple and promising method for preparing stable biocatalyst of Serratia marcescens lipase

Crosslinking of enzyme aggregates is a promising method for enzyme immobilization. In this work, crosslinked enzyme coaggregates of Serratia marcescens lipase with polyethyleneimine (CLECAs-SML-PEI) were prepared using polyethyleneimine (PEI) as coprecipitant and glutaraldehyde as crosslinking reagent. The crude lipase solution at a low protein concentration (0.1 mg/ml), with PEI at a mass ratio of 3:1 (PEI/protein, w/w), was found to be most adequate for the coprecipitation of SML. After crosslinking of the coaggregate of SML-PEI with 0.2% (w/v) glutaraldehyde under ambient temperature, over 70% of the total lipase activity was recovered. Compared with the free SML, the optimum temperature of the CLECAs-SML-PEI was enhanced from 50 °C to 60 °C and its thermal stability was also significantly improved. CLECAs-SML-PEI showed excellent operational stability in repeated use in aqueous–toluene biphasic system for asymmetric hydrolysis of trans-3-(4′-methoxyphenyl)glycidic acid methyl ester (MPGM), without significant inactivation after 10 rounds of repeated use.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights▶ A stable biocatalyst of S. marcescens lipase was prepared by the method of CLECAs. ▶ Polyethyleneimine was used as sole precipitating agent in the preparation of CLECAs. ▶ CLECAs-SML-PEI showed no significant inactivation after 10 rounds of repeated use.