Degradation of Microcrystalline Cellulose with Organic Electrolyte Solution Pretreatment for the Efficient Production of Hyperoside in Escherichia coli

The production of high-value bioproducts using cellobiose and glucose is crucial for cellulose utilization. Cellobiose as a glycosyl precursor for biosynthesizing uridine diphosphate glucose (UDP-glucose) has been used for the glycosylation of flavonoids. Hyperoside is the key pharmacological component in Hypericum monogynum L and has unique pharmacological activities. In this study, a recombinant strain was constructed by introducing glycosyltransferase from Petunia hybrida (PhUGT), UDP-glucose epimerase (GalE), and the cellobiose phosphinylation route to produce hyperoside. By optimizing the fermentation conditions, the maximal hyperoside production reached 3274 mg/L. Subsequently, microcrystalline cellulose was pretreated with organic electrolyte solution (OES) to produce cellobiose and glucose, which was used as the carbon source and glycosyl precursor for hyperoside production. The hydrolysis yield of cellulose was increased from 30.1 to 91.7%, and the yield of cellobiose was increased by 298% with OES pretreatment. The highest yield of hyperoside in the recombinant strain reached 2013.2 mg/L when the optimal cellulose enzymatic solution was used as the glycosyl precursor. Finally, 100 g of cellulose could yield 60.25 g of glucose and 39.5 g of cellobiose, which served as the glycosyl precursor to produce 20.13 g of hyperoside. This study provides a novel method for the production of hyperoside by using enzymatic hydrolysis of microcrystalline cellulose.