Cyanophycin production from feather hydrolysate using biotechnological methods

Cyanophycin is a bacterial storage polymer for carbon, nitrogen and energy with emerging industrial applications. As efficient cyanophycin production is enhanced by peptone, but commercial peptones are very expensive, thereby increasing the overall production cost, an enzymatically produced feather hydrolysate (FH) is assessed as a cheap replacement of peptone to lower the costs and make cyanophycin production more economically feasible. Keratinase production using feather as the sole carbon/nitrogen source by S.pactum 40530 at 30-L fermentation scale was achieved within 93 h with degradation rate of 96.5%. A concentration of 60 g/L of FH, generated by keratinolytic activity (8 × 10³ U g^-1L^-1d^-1) within 24 h, was used as the main carbon/peptone source to produce cyanophycin. The growth performances of E. coli DapE/L using FH was compared to that of casamino acids (CA) and up to 7.1 ± 0.4 and 5.3 ± 0.3 g/L of cell mass were obtained after 72 h from FH and CA, respectively. Cyanophycin production yielded 1.4 ± 0.1g/L for FH with average molecular mass of 28.8 and 1.4 ± 0.2 for CA with average molecular mass of 35.3, after 60 h. For the first time, FH generated by biotechnological methods from environmentally problematic, abundant and renewable feather bioresource was successfully used for cyanophycin biopolymer production.