Rapid Conversion of Chicken Feather to Feather Meal Using Dimeric Keratinase from Bacillus licheniformis ER-15

Protein determination: Protein in supernatant was measured at A280 and 1 absorbance was considered as 1mg/ml protein using bovine serum albumin as standard. Production and downstream processing of keratinase from Bacillus licheniformis ER-15Enzyme production: Keratinase was produced in soyflour feather medium in 60h as reported earlier [10].A loopful bacterial culture was inoculated in 50ml nutrient broth in 250ml Ehrlenmeyer flask, grown at 37°C, 200rpm for 16h and used as seed culture.This seed culture was again grown in nutrient broth for 16h in similar conditions and used as inoculum for production medium.Four hundred ml of production medium in 2L flask (0.4%w/v soyflour, 3%w/v glucose, 0.3w/v KH2PO4, 0.9%w/v K2HPO4, 0.5%w/v feather) was inoculated with 4% v/v inoculum and incubated at 250rpm, 37°C for 60h.Sedimentation and microfiltration: After 60h of production, fermentation broth was collected in a beaker and kept at room temperature in static condition for 24h.Most of the bacterial cells were settled along with feather meal at the bottom of beaker, supernatant was decanted and micro filtered through 0.2μ filters (MDI, India) using vacuum pump.This micro filtered supernatant was concentrated and used as enzyme.Enzyme concentration and shelf life: Micro filtered supernatant was concentrated using 85% saturation of ammonium sulphate.Precipitated enzyme was collected after centrifugation, dissolved in pH 7