An optimization approach to scale up keratinase production byStreptomyces sp. 2M21 by utilizing chicken feather

The aim of this study was to optimize the culture conditions for keratinase production by a new isolate, Streptomyces sp. 2M21 utilizing chicken feather as an alternative low-cost substrate. Contribution of different independent fermentation variables on keratinase activity was investigated by Plackett-Burman design. Parameters that have the highest contribution were selected for the optimization experiments which were carried out by using response surface methodology (RSM). Relative and mutual effects of fermentation variables on keratinase activity were analyzed with "23 Full Factorial Central Composite Design". Cultivation processes were implemented in 250ml Erlenmeyer flasks containing 50ml medium. Maximum keratinase activity was obtained under optimal conditions of 28°C, 5.0gl-1 chicken feather and 5.5 days of process time. As a result of the optimization studies, a 15 fold increase in keratinase activity was reached compared to the unoptimized conditions. Furthermore, similar results were obtained in the 2l bioreactor under optimized conditions. © 2015 Elsevier Ltd.MUH.005 MAG-112M250This work was supported by The Research Fund of Ege University (Grant number 11.MUH.005 ) and supported in part by TUBITAK (The Scientific and Technical Research Council of Turkey) (Grant number MAG-112M250 ). -