Biocatalytic strategies in producing ginsenoside by glycosidase-a review / 生物工程学报

Panax ginseng is a traditional Chinese medicine with significant pharmaceutical effects and wide application. Through orientational modification and transformation of ginsenoside glycosyl, rare ginsenosides with high antitumor activities can be generated. Traditional chemical methods cannot be applied in clinic. because of extremely complex preparation technologies and very high cost Transformations using microorganisms and their enzymatic systems provide the most feasible methods for solving the main problems. At present, the key problems in enzymatic synthesis of ginsenosides include low specific enzyme activities, identity of enzymes involved in the enzymatic synthesis, and their catalytic mechanisms, as well as nonsystematic studies on structural bioinformatics; specificity of enzymatic hydrolysis for saponin glycosyl has been rarely studied. Many reviews have been reported on glycosidase molecular recognition, immobilization, and biotransformation in ionic liquids (ILs), whereas ginsenoside transformation and application have not been systematically studied. To evaluate theoretical and applied studies on ginsenoside-oriented biotransformation, by reviewing the latest developments in related fields and evaluating the widely applied biocatalytic strategy, this review aims to evaluate the ginsenoside-oriented transformation method with improved product specificity, increased biocatalytic efficiency, and industrial application prospect based on the designed transformations of enzyme and solvent engineering of ILs. Therefore, useful theoretical and experimental evidence can be obtained for the development of ginsenoside anticancer drugs, large-scale preparation, and clinical applications in cancer therapy.

MICROBIAL ENZYME CONVERSION OF L-CYSTEBSE AND L-CYSTINE / 微生物学通报

Pseudomonas sp. TS1138 isolated from soil samples was able to form L-cysteine from DL-2-Amino-△2-Thia-zoline-4-Carboxylic Acid (DL-ATC) after cultured 16 hours . The optimum carbon and nitrogen soruces of strain growth and enzyme formation are glucose and urea. This enzyme was induced by DL-ATC. The product was identified to be L-Cysteine based on thin layer chromatography, optical rotation and HPLC studies.