Abstract: Objective: This study aimed to examine the effect of Cu2+ on the proliferation of Paenibacillus polymyxa and the conversion of ginsenosides. Methods: A microplate reader and HPLC were used for this study. Results: Cu2+ at 10–50 mg/L improved P. polymyxa proliferation and the best effect was observed at 30 mg/L, where it entered the logarithmic growth phase earlier 1 d and the biomass was significantly increased as compared with the control group. The presence of Cu2+ at 10–50 mg/L in the culture medium improved?the conversion of ginsenosides by P. polymyxa and its effect was strongest at 30 mg/L. However, when the concentration of Cu2+ exceeded 100 mg/L, the conversion of ginsenosides was inhibited, and this inhibition was increased with increasing Cu2+ concentration. Conclusion: A Cu2+ concentration of 30 mg/L improved P. polymyxa proliferation and the conversion of ginsenosides.

Key words: Paenibacillus polymyxa, Cu2+, growth curve, conversion of ginsenosides, proliferation