Biocatalytic Synthesis of Calycosin-7-O-β-D-Glucoside with Uridine Diphosphate–Glucose Regeneration System

Identification and engineering of a sucrose synthase from Stevia rebaudiana for glycosylation applications

Sucrose synthase (SuSy) is a unique glycosyltransferase that can be utilized in the production of nucleoside monosaccharides, such as diphosphate (UDP)-glucose, which serve as essential sugar donors for the glycosylation reactions catalyzed by UDP-dependent glycosyltransferases (UGTs). The selection of an appropriate SuSy coupled with a UGT is crucial for achieving the efficient synthesis of glycoside products. In this study, three candidate SuSy genes were identified from the transcriptome sequencing of Stevia rebaudiana, among which SrSUS1 was found to be expressed and active in Escherichia coli. The optimal temperature and pH for SrSUS1 were determined to be 55°C and pH 7.0, respectively. A variant SrSUS1T49A/L90P/V104E was generated based on a consensus sequence strategy, exhibiting a 3.6-fold increase in activity and the enhanced affinity for sucrose (Km = 52.32 mM), as well as the improved thermal stability and catalytic efficiency. By coupling SrSUS1T49A/L90P/V104E with glycosyltransferase UGTAn85Q23E/N65D or UGT76G4, respectively, the production of 163.32 mM (43.63 g/L) of 2-phenylethyl-β-D-pyranoside and 72.29 mM (93.35 g/L) of rebaudioside M was achieved within 24 h in one-pot, two-enzyme fed-batch reactions. This study provides new insights into plant-derived SuSys and presents a promising biocatalyst for industrial glycosylation applications.

Biocatalytic Process Optimization

Biocatalysis refers to the use of microorganisms and enzymes in chemical reactions, has become increasingly popular and is frequently used in industrial applications due to the high efficiency and selectivity of biocatalysts [...]

Recent Advances in Enzymatic and Chemoenzymatic Cascade Processes

Cascade reactions have been described as efficient and universal tools, and are of substantial interest in synthetic organic chemistry. This review article provides an overview of the novel and recent achievements in enzyme cascade processes catalyzed by multi-enzymatic or chemoenzymatic systems. The examples here selected collect the advances related to the application of the sequential use of enzymes in natural or genetically modified combination; second, the important combination of enzymes and metal complex systems, and finally we described the application of biocatalytic biohybrid systems on in situ catalytic solid-phase as a novel strategy. Examples of efficient and interesting enzymatic catalytic cascade processes in organic chemistry, in the production of important industrial products, such as the designing of novel biosensors or bio-chemocatalytic systems for medicinal chemistry application, are discussed

Biocatalytic Synthesis of a Novel Bioactive Ginsenoside Using UDP-Glycosyltransferase from Bacillus subtilis 168

Ginsenoside Rg3 is a bioactive compound from Panax ginseng and exhibits diverse notable biological properties. Glycosylation catalyzed by uridine diphosphate-dependent glycosyltransferase (UGT) is the final biosynthetic step of ginsenoside Rg3 and determines its diverse pharmacological activities. In the present study, promiscuous UGT Bs-YjiC from Bacillus subtilis 168 was expressed in Escherichia coli and purified via one-step nickel chelate affinity chromatography. The in vitro glycosylation reaction demonstrated Bs-Yjic could selectively glycosylate the C12 hydroxyl group of ginsenoside Rg3 to synthesize an unnatural ginsenoside Rd12. Ginsenoside Rd12 was about 40-fold more water-soluble than that of ginsenoside Rg3 (90 μM). Furthermore, in vitro cytotoxicity of ginsenoside Rd12 against diverse cancer cells was much stronger than that of ginsenoside Rg3. Our studies report the UGT-catalyzed synthesis of unnatural ginsenoside Rd12 for the first time. Ginsenoside Rd12 with antiproliferative activity might be further exploited as a potential anticancer drug.