Optimization of fermentation parameters and mutagenesis of Glarea lozoyensis ATCC 20868 towards pneumocandin B0 production.

Pneumocandin B0 is a secondary metabolite that acts as a precursor for caspofungin acetate, an antifungal drug. This study focuses on the development of an upstream process for pneumocandin B0 production through fermentation condition optimization and mutagenesis. A response surface methodology (RSM)-based central composite design (CCD) was employed to increase the production of pneumocandin B0 in Glarea lozoyensis ATCC 20868. The four independent variables (mannitol, fructose, soybean meal, and pH) were chosen at three different levels to obtain the optimum conditions for pneumocandin B0 production. The optimized process conditions using RSM-CCD resulted in 29.4 mg/L pneumocandin (11.76-fold increase compared with that of wild-type). To improve pneumocandin B0 production, mutagenesis (physical/chemical) was also performed using gamma-irradiation and methyl methane sulfonate (MMS). The best-performing MMS-induced mutant strain in optimized medium resulted in increased pneumocandin B0, i.e., 74.17 mg/L (29-fold increase compared with that of wild-type), at the 2-L shake flask level. Additionally, morphological analysis using scanning electron microscopy revealed significant structural changes in the mutant strains, including altered hyphal and mycelial morphology. These findings suggest that mutagenesis not only enhances production but also modifies cellular physiology. In conclusion, this study presents an integrated strategy that combines media optimization and mutagenesis to significantly increase pneumocandin B₀ production.