Improving the thermostability of feruloyl esterase by DNA shuffling and site-directed mutagenesis

Abstract

Feruloyl esterases (FAE) with high thermostability are greatly desired for efficient and economical industrial processes. A DNA shuffling strategy was applied to generate a chimeric library from four homologous FAEs originated from fungi. Chimeras with enhanced thermal stability compared to the parental FAEs were identified, which contained segments from 3 or 4 of the parental enzymes. After further incorporation of 2–4 additional beneficial mutations, the half-lives of inactivation of the chimeras at 65°C were increased by up to 22 fold when compared to the most stable parental FAE. As a result, the release of ferulic acid from steam-exploded corn stalk using the best chimera was enhanced by 12.8-fold when compared to the best parental FAE.