Production of sugars from mixed hardwoods for use in the synthesis of sugar fatty acid esters catalyzed by immobilized‐stabilized derivatives of Candida antarctica lipase B

Abstract

AbstractThe synthesis of sugar fatty acid esters (SFAEs) from lignocellulosic biomass and oleic acid (C18:1) was catalyzed by immobilized‐stabilized derivatives of Candida antarctica lipase B in a methyl ethyl ketone medium. After steam‐explosion pretreatment of mixed hardwoods and enzymatic hydrolysis at 15%wt solids, xylose and glucose were purified/concentrated to a mass ratio of ~3 to 1. These lignocellulosic sugars were superior to commercial sugars as the carbohydrate source for the esterification reaction in terms of sugar conversions. The highest conversions were obtained using 1.5% w/v of Novozyme 435 (N435, uncoated) as the biocatalyst for the synthesis of SFAEs. Coating the N435 with polyethyleneimine (PEI) prevented enzyme leakage into the reaction medium and produced 35% and 50% higher xylose and glucose conversions to SFAEs, respectively, at the same enzyme loading. After six 24 h reuse cycles with the PEI‐coated N435, xylose conversion decreased by 44%, while a 65% reduction in xylose conversion was observed with the uncoated lipase. Mass spectrometry analysis confirmed the production of xylose and glucose mono‐ and di‐esters. Our purified product presented an emulsion capacity (EC) close to that of a commercial sugar ester and the ECs of the xylose oleate, laurate, and palmitate synthesized in previous studies. © 2023 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.