Monday, August 13, 2012
Columbia Hall, Terrace Level (Washington Hilton)
Feathers are rich in aminoacids and can be employed as a dietary protein supplement for animal feed. Feathers degradation by keratinase represents an alternative technology for improving their nutritional value. Other potential applications of keratinase include use in the leather industry, detergent application, medicine and the pharmaceutical industry for acne or psoriasis treatment and the elimination of human callus. In the present study, experimental designs were applied to optimize four significant variables: temperature, substrate concentration (feathers), aeration and agitation speed. This study was conducted to optimize the production of keratinase by Bacillus amyloliquefaciens. The central composite rotatable design (CCRD) with four independent variables, each at four levels with eight star points and three replicates at the center points, was used to develop a second order polynomial model (total 27 experiments) that determined the optimal values of variables for keratinase production in bioreactor. The results showed that higher feather degradation was obtained when fermentation are performed under 250 rpm, 30°C, 1vvm and 2.4 % feathers (97%), maximum activity keratinolytic was also observed under these conditions (59 U.mL).There was a tendency that higher feather concentration used in the culture medium and higher speed of agitation employed increase keratinolytic activity, with significant interaction X2X4. According to the results, we concluded that the strain B. amyloliquefaciens showed potential for use in biotechnological processes.