Large scale keratinase prduction from chicken feathers and seperation and purification processes

Chicken feather with regards to its high keratin content can be considered as a potential raw material for industrial applications. However its rigid structure giving degradation resistance with common proteases, limits its direct usage as a substrate. There are few microorganisms like fungi, Bacillus and Streptomyces strainshave the ability to degrade feathers using keratinase enzymes. The aim of this study was to produce keratinase using Streptomyces sp. 2M21 in different bioreactors starting with 2L and scaling step by step using 5, 10 and 20 L bioreactors and to perform enzyme purification and characterization. Keratinase production in 2 L bioreactor was 351 U/ml. Keeping impeller tip speed and oxygen mass transfer coefficient constant, scaling up to 5, 10 and 20 L bioreactors were performed with a detected keratinase activity of 353, 358 and 355 U/ml respectively. Following the bioreactor productions keratinase concentrated via ultrafiltration and purified using DEAE ion exchange chromatography with step by step salt gradient elution. Characterization studies showed that the keratinase belongs to the serine protease group, having a molecular weight of 44.8 kDa, with an optimum activity temperature of 30 oC and optimum pH of 9 which were determined by response surface methodology. On the other hand enzyme can protect its activity up to 90% for 30 days under +4 oC storage conditions. The cost analysis and product yields were also determined based on 20 L scale.