Isolation and screening of keratinase enzyme producing Bacillus mojavensis par01 from poultry farm
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Abstract
Feathers are the most prevalent waste produced by poultry industry. In addition to seriously polluting the environment, an excessive amount of feathers also wastes protein resources. Currently, one method under consideration is the degradation of poultry waste by bacteria that produce keratinase. The keratinase plays a significant role in the biodegradation of chicken waste into animal feed and fertilizers. In this study, keratinolytic bacterium was isolated, screened, identified and cultural conditions were optimized for the maximum production of enzyme. Keratinase producing bacterium was isolated from soil of poultry farm and screened on skim milk agar followed by enzyme production using submerged fermentation. The isolate showing maximum zone of hydrolysis on skim milk agar was identified as Bacillus mojavensis on the basis of morphological, biochemical and contigs sequences of the strain Bacillus par01 and related bacteria using blast search and named as Bacillus mojavensis par01. Maximum keratinase production (160 U/mL) was achieved in 72 h using a minimal growth medium containing 1% (w/v) feather meal at 37 °C, pH 7.5 at 150 rpm. The crude keratinase was purified using ammonium sulfate precipitation, DEAE Sephadex A-50 and Q-Sepharose chromatographic techniques. The molecular mass of purified keratinase was 30 kDa. The overall purification factor was 13.5 fold, final yield was 40% and the specific activity of final product was 560 U/mg. This study shows that the good feather-degrading capacity of the selected B. mojavensis par01 strain may be used for its prospective biotechnological applications in the processing of poultry waste.
Keywords: Feather meal; Fermentation; Keratin; Precipitation; Purification