Bioresource Technology, Vol.223, 149-156, 2017
Production of epsilon-poly-lysine by Streptomyces albulus PD-1 via solid-state fermentation
The aim of this study was to produce epsilon-poly-lysine (epsilon-PL) by Streptomyces albulus PD-1 through solid-state fermentation (SSF) using agro-industrial residues. Maximum epsilon-PL production (86.62 mg/g substrate) was obtained a mixed substrate of rapeseed cake and wheat bran (2: 1, w/w) supplemented with glucose (4%, w/w), (NH4)(2)SO4 (3%, w/w), with an initial moisture content of 65%, initial pH of 7.0 and inoculum size of 13% v/w, incubated at 30 degrees C for 8 days. The results of scanning electron microscopy indicated that the filamentous thallus could penetrate the substrate surface. Moreover, repeated-batch SSF was successfully conducted 8 times using 10% substrate as seeds for the next fermentation cycle, and the results suggest that repeated-batch SSF is more efficient because of the shortened lag phase. To the best of our knowledge, this is the first report on epsilon-PL production using the SSF process. (C) 2016 Elsevier Ltd. All rights reserved.
Keywords:Streptomyces albulus PD-1;epsilon-Poly-lysine;Solid-state fermentation;Agro-industrial residues;Repeated-batch fermentation