Identification Of Bacillus Thuringiensis From Cosmetics And Analysis Of The SOD Activity For Ultraviolet Radiation Resistance

Bacillus thuringiensis(Bt) have been widely used as one of the most effective microbial pesticides all around the world,and its persistent is one of the important factors in application. In this study, one strain of fungi and eleven strains of bacteria were isolated from 184 cosmetic samples, including two Bacillus thuringiensis strains, two Bacillus cereus strains, two Proteus vulgaris strains, one Paenibacillus sp. strain, one Pseudomonas putida strain, one Bacillus sp. strain, one Micrococcus sp. strain and one Cladosporium sphaerospermum strain. The isolating rate of samples with microorganism in all samples was 5.43%, the isolating rate of microorganism in all samples was 6.52% and the isolating rate of Bt strains in all samples was 1.09%. This paper analysed and proved that the isolating rate of Bt strains in all samples was fairly relevant to whitening ingredients in cosmetic. Arbutin and glabridin benifited the breeding of Bt strains, linoleic acid, oligomeric proantho cyanidins, ascorbyl palmitate and gallic acid (pH 6.5) could inhance the survival rate of Bt strains under the pressure of preservative in cosmetics.After screening, IPP, Tween20, Tween80, PEG6000 and PVP-K30 were found could promote the growth of BRC-ZYR6, and can increase the specific activity of intracellular SOD in different degree, and a result that the ability of UV resistance was strengthened respectively, the survival rete was 64.9%、49.7%、53.1%、49.4% and 47.0%, negative control was only 34.2%. Besides, after adding SOD extracted and purified from BRC-ZYR6, the ability of UV resistance of BRC-ZYR6 was increased by 127.1% compared to the control group.SOD of BRC-ZYR6 was purified by 12.9 folds using precipitate of ammonium sulphate, gel filtration and electroelution, the specific activity was up to 8986 U/mg protein. The analysis demonstrated that the SOD of BRC-ZYR6 presented typical character of Mn-SOD. The optimum culture time for SOD was eighteen hours, temperature was 40℃ and pH range was 8.0-10.0. The subunit molecular weight of the purified SOD was determined 24.0 kDa by SDS-PAGE.