Ecologically Safe Method for Feather Biodegradation by a Novel Isolated Bacillus thuringiensis NJY1

Abstract

To isolate feather-degrading bacterial strain and establish optimum conditions for feather degradation. Different feather-degrading bacteria were isolated from slaughterhouse using enrichment medium with feather as sole carbon and nitrogen source. A strain with high keratinolytic activity was identified as Bacillus thuringiensis NJY1 according to physiological, biochemical, and morphology characteristics and 16S rRNA gene sequence. The optimal conditions was achieved at initial pH 8.0, inoculum size 1% with 18h old inoculum, incubation temperature 37°C, agitation rate 200rpm and the medium composed of 20g feather meal, 2.5g beef extract, 0.5g NaCl, 0.3g K <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> HPO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> , 0.4g KH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> PO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> , 0.1g MgSO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> -7H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O in 1000mL distilled water. Maximum protease production attained at the optimal conditions was (72U/mL) after 24h cultivation. Bacillus thuringiensis NJY1 and the protease produced provide an interesting potential for the microbiological or enzymatic hydrolysis of feather to be used as animal feed supplement.