Efficient Bioproduction of p-Hydroxybenzaldehyde β-Glucoside from p-Hydroxybenzaldehyde by Glycosyltransferase Mutant UGTBL1-Δ60

Simple SummaryThis study enhanced the relative activity of glycosyltransferase UGTBL1 through engineering mutations near its loop regions. The engineered enzyme efficiently catalyzed the glycosylation of the lignin-derived compoundp-hydroxybenzaldehyde (C7H6O2), enabling the environmentally benign synthesis of a Helicid analogue (p-hydroxybenzaldehydeβ-glucoside (C13H16O7)). Accordingly, this work provided novel insights for lignin valorization. Under optimized reaction conditions (35 °C, pH 7.5, 200 mM glucose (C6H12O6)), an exceptional yield of 97.8% forp-hydroxybenzaldehydeβ-glucoside was attained within 10 h using 2 mMp-hydroxybenzaldehyde substrate. Biotransformation of 3 mMp-hydroxybenzaldehyde (366.4 mg/L) afforded up to 2.7 mM of targetβ-glucoside product (767.5 mg/L). This research establishes a simpler, more economical, and sustainable enzymatic approach for the efficient synthesis ofp-hydroxybenzaldehydeβ-glucoside, offering significant potential benefits for pharmaceutical, cosmetic, or agricultural applications.Lignin, as one of the three primary components of renewable lignocellulosic biomass, can be converted into aromatic platform chemicals and holds significant potential for high-value applications.p-Hydroxybenzaldehyde is a compound derived from lignin. In this study, the mutant Δ60 of the glycosyltransferase UGTBL1 derived fromBacillus licheniformiswas adopted to catalyze the glycosylation reaction ofp-hydroxybenzaldehyde, producing a bioactive compound Helicid analogue (p-hydroxybenzaldehydeβ-glucoside). Truncation mutations targeting loop regions may reduce local flexibility, thereby facilitating enhanced access ofp-hydroxybenzaldehyde to the active site pocket and promoting relative activity. Under optimal conditions (35 °C, pH 7.5, and glucose 200 mM), a high yield of 97.8% forp-hydroxybenzaldehydeβ-glucoside was achieved from 2 mMp-hydroxybenzaldehyde within 10 h. The conversion of 3 mMp-hydroxybenzaldehyde (366.4 mg/L) yielded up to 2.7 mM (767.5 mg/L) ofp-hydroxybenzaldehydeβ-glucoside within 48 h. According to the molecular docking results, the CDOCKER energy value of mutant Δ60 was lower than that of the wild-type, at −16.0 kcal/mol. To our knowledge, this is the first example of an efficient and environmentally sustainable approach for the synthesis ofp-hydroxybenzaldehydeβ-glucoside, providing a new insight for the valorization of lignin into valuable biobased chemicals.