Notice of RetractionResearch on Improving Keratinase Vitality of Bacillus Subtilis Based on Compound Mutation

Notice of Retraction

After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE´s Publication Principles.

We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.

The presenting author of this paper has the option to appeal this decision by contacting TPII@ieee.org.

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.