Optimization of medium for enhancement of ε-Poly-L-Lysine production by Streptomyces sp. M-Z18 with glycerol as carbon source

The goal of this study was to increase ε-Poly-L-Lysine (ε-PL) production by Streptomyces sp. M-Z18 through optimization of the culture medium. Glycerol, (NH4)2SO4 and K2HPO4 were the key factors in the fermentation according to the results obtained from the Plackett–Burman experimental design. The optimal concentration of the three factors was further investigated according to the central composite design and determined to be 59.48, 4.43 and −0.49 g/L, respectively. Under optimal conditions, a ε-PL concentration of 2.27 ± 0.15 g/L was obtained. Compared with glucose, fermentation of glycerol afforded 2.8-fold and 6.3-fold the ε-PL titer and yield, respectively. Therefore, glycerol may be an efficient carbon source for ε-PL production by Streptomyces sp. M-Z18.