Production of natamycin by Streptomyces gilvosporeus Z28 through solid-state fermentation using agro-industrial residues

At present, submerged fermentation (SmF) is the unique approach for natamycin production. This study aims to propose a strategy for natamycin production through solid-state fermentation (SSF). The maximum natamycin concentration (9.62 mg.gds(-1)) was obtained with a substrate mixture containing wheat bran, rapeseed cake, rice hull and crude glycerol in a 5 L flask at 28 degrees C, and the initial moisture content and inoculum size was set as 70% and 15%, individually. A 30 L scale-up fermentation showed similar parameters and produced 9.27 mggds natamycin at the 8th day. Besides, natamycin could be continuously produced by repeated-batch fermentation for 5 cycles through SSF. Compared to SmF, SSF led to a 50.05% cost reduction of raw materials, less energy consumption and waste water discharge, which was of great significance in industrial fermentation. To our best knowledge, this is the first report on natamycin production through SSF process.