Enzymatic reduction of levoglucosenone by an alkene reductase (OYE 2.6): a sustainable metal- and dihydrogen-free access to the bio-based solvent Cyrene®

Abstract

Levoglucosenone (LGO) has been successfully converted into the green polar aprotic solvent 2H-LGO (aka Cyrene®) through an enzymatic process involving alkene reductases: wild-type Old Yellow Enzyme 2.6 (OYE 2.6 wt.) from Pichia stipitis and its mutant (OYE 2.6 Tyr⁷⁸Trp) present the best conversion rates. This enzymatic process has been optimized in order to avoid the formation of the side-product (1R,2S)-2-hydroxy-6,8-dioxabicyclo[3.2.1]octan-4-one (OH-LGO) and reach total conversion (99%). Cyrene® was then successfully isolated by continuous extraction in quantitative yield (99%).