A total of approximately 400 bacterial strains were isolated from 73 plastic wastes collected from 14 different regions. Nineteen isolates that form clear zones both on tributyrin and poly ε-caprolactone (PCL) agar, were identified based on 16S rRNA gene sequences. Among these, Bacillus sp. KY0701 that caused the highest weight loss of PCL films in minimal salt medium, was selected for cutinase production. The highest enzyme activity (15 U/mL) was obtained after 4 days of incubation at 50°C, pH 7.0 and 200 rpm in a liquid medium containing 1.5% (w/v) apple cutin and 0.1% (w/v) yeast extract. The purified enzyme was stable at high temperatures (50-70°C) and over a wide pH range (5.5-9.0). The relative activity of cutinase was at least 75% in the percent of various organic solvents. The apparent Km and Vmax values of the cutinase for p-nitrophenyl butyrate were 0.72 mM and 336.8 µmol p-nitrophenol/h/g, respectively. In addition, it showed high stability and compatibility with commercial detergents. These features of cutinase obtained from Bacillus sp. KY0701 make it a promising candidate for application in the detergent and chemical industries. In our best knowledge, this is the first report for cutinase production and characterization produced by a Bacillus strain.
Keywords: Cutinase; PCL degradation; detergents; thermotolerant.