新细菌转化生产人参皂苷Rg_3的条件研究

Transformation of protopanaxadiol saponin to ginsenoside-Rg_3 by Phycicoccus sp.BXN5-13

研究了新筛选的细菌Phycicoccus sp.BXN5-13转化人参二醇类皂苷生成Rd和Rg3皂苷酶反应条件。结果表明,该细菌产生的人参皂苷酶为胞内酶,最佳产酶发酵条件为在含胰蛋白胨10 g/L、酵母膏5 g/L、NaCl 10 g/L的培养基中加入产酶诱导物,即人参茎叶总皂苷,在35℃培养72 h。其粗酶反应最佳条件:底物质量浓度为1 mg/mL,最适pH为6,在45℃反应24 h。其发酵液与人参二醇类皂苷反应后,用薄层层析法与高效液相色谱法检测结果;其酶液将Rb1等人参二醇类皂苷,转化为人参皂苷Rd,将Rd进一步转化为人参皂苷Rg3;转化率为44%。

The ginsenosidase was produced by Phycicoccus sp. BXNS-13 for transformation of Rb1 and other protopanaxadiol saponin to the ginsenoside Rd and Rg3. The ginsenosidase was an intracellular enzyme that produced maximally when cultured in the medium containing 10 g/L triptone, 5 g/L yeast extract and 10 g/L NaCl and ginsenoside at 35℃ for 72 h. The optimal condition for enzymatic hydrolysis of ginsenoside was as pH 6.0 at 45℃ for 24 h. The transformation rate of ginsenoside-Rg3 was 44%.