Efficient valorization of food waste oils to renewable biodiesel by a Candida antarctica lipase B mutant that catalyzes the ester synthesis reaction in the presence of water

Abstract

Food waste oil (FWO) is the most suitable raw material for economic biodiesel (BD) production, owing to its low price, sufficient supply, and waste disposal diversion. However, water in FWO inhibits BD production by Candida antarctica lipase B (CALB) which must be overcome. Here, a mutant lipase CALB1422 that catalyzes the ester synthesis in the presence of water was developed. The CALB1422 showed 91.1 % and 72.6 % BD conversion rates for soybean oil containing 2 % and 8 % water, respectively; wild-type CALB was inhibited to 29.8 % in the presence of 2 % water. It is presumed that the water attraction of the mutation site freed the catalytic site from water, which was confirmed by molecular dynamics simulation. From crude FWOs, the CALB1422 exhibited up to a 2.1-fold increased BD conversion yield against commercial lipase (Novozym 435). The mutant lipase is an efficient and reusable biocatalyst to produce sustainable BD from waste oils.