Notice of Retraction: Research on Improving Keratinase Vitality of Bacillus Subtilis Based on Compound Mutation

Abstract

This paper presented a method to separate Bacillus subtilis from natural environment, which could be used to produce keratinase. Through the use of ultraviolet ray and sodium nitrite compound mutation, a mutation strain FUN30.2 was produced that is capable to yield high vitality of keratinase. The vitality of keratinase was 75.9% higher than that before the mutation. This was achieved by optimizing the fermentation medium of FUN30.2. The optimum fermentation medium had the following components: 5.5% of feather meal, 0.8% of maize silage 0.018 mol/L of K+ concentration, 0.065 mol/L of Mg2+ concentration, 0.072 mol/L of Ca2+ concentration, 0.010 mol/L of Fe2+ concentration, and 0.088 mol/L of Na+ concentration. On the optimized fermentation medium, the highest yielding rate for producing enzyme by the strain was 1.117 U/mL, 25.67% higher than that before the optimization. The amino acid concentration in the fermentation medium fluid reached 22.66 mg/mL. The method provided in this paper was simple, and low cost. Therefore, it could be used in industrial production of good bacteria and ratio of fermentation medium components for bio-fermentation of feather meal.