EFFECTS OF SALTS IN BIODIESEL DERIVED CRUDE GLYCEROL ON VANCOMYCIN PRODUCTION FROM AMYCOLATOPSIS ORIENTALIS ATCC® 19795™

Abstract

Bioconversion of crude glycerol (CG), the primary byproduct in biodiesel generation, is currently of great interest due to its promising potential in producing chemicals of high commercial interest. The efficient use of CG is still limited primarily due to the presence of impurities that may vary in composition based on the parent feedstock, biodiesel generation process, and any recovery/ purification conducted. In this study, laboratory scale fermentation of vancomycin using Amycolatopsis orientalis ATCC® 19795™ was analyzed based on the presence of salts as an impurity in biodiesel derived CG. Results showed that CG as the sole carbon source inhibited the cell growth, but the vancomycin production was approximately the same (158±2 mg L-1) as that of refined glycerol (RG)-based media at varying initial glycerol concentrations studied (5 g L-1 to 40 g L-1). NaCl as an impurity in biodiesel derived CG reduced both the growth yield coefficient (YX/S) and vancomycin formation at high concentrations. Among other salts tested are NaNO3 and KCl. NaNO3 (0.8 g L-1) supplemented media generated a higher YX/S (1.1 g biomass (g glycerol consumed)-1) and a similar vancomycin concentration (193 mg L-1) compared to the media with added NaCl (YX/S of 0.4 g biomass (g glycerol consumed)-1 and a vancomycin concentration of (190 mg L-1)). Relatively, both the YX/S (0.55 g biomass (g glycerol consumed)-1) and vancomycin concentration (135 mg L-1) was reduced in KCl (0.7 g L-1) supplemented media. The results suggest the potential of using CG (with salts i.e., NaCl as impurities) as an excellent low-cost alternative for RG in fermentation of vancomycin using Amycolatopsis orientalis ATCC® 19795™.