Economical production of poly(ε-l-lysine) and poly(l-diaminopropionic acid) using cane molasses and hydrolysate of streptomyces cells by Streptomyces albulus PD-1

Poly(ε-l-lysine) (ε-PL) and poly(l-diaminopropionic acid) (PDAP) co-production by Streptomyces albulus PD-1 from cane molasses and hydrolysate of strepyomyces cells (HSC) was investigated for the first time in this study. The optimal initial total sugar concentration of the cane molasses pretreated with sulfuric acid was determined to be 20 g L−1, and HSC could substitute for yeast extract for ε-PL and PDAP co-production. When fed-batch fermentation was performed in 1 t fermentor with pretreated cane molasses and HSC, 20.6 ± 0.5 g L−1 of ε-PL and 5.2 ± 0.6 g L−1 of PDAP were obtained. The amount of strepyomyces cells obtained in one fed-batch fermentation is sufficient to prepare the HSC to satisfy the demand of subsequent fermentations, thus the self-cycling of organic nitrogen source becomes available. These results suggest that the low-cost cane molasses and HSC can be used for the economical production of ε-PL and PDAP by S. albulus PD-1.