Biochemical and biotechnological studies on a novel purified bacillus cholesterol oxidase tolerant to solvent and thermal stress |
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Authors: | Fathy N. ElBaz Rawia F. Gamal Ashraf F. ElBaz Nasser E. Ibrahim |
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Affiliation: | 1. Department of Industrial Biotechnology, Genetic Engineering and Biotechnology Research Institute, University of Sadat City (USC), Sadat City, Egypt;2. Department of Agricultural Microbiology, Faculty of Agriculture, Ain Shams University, Cairo, Egypt;3. Department of Bioinformatics, Genetic Engineering and Biotechnology Research Institute, University of Sadat City (USC), Sadat City, Egypt |
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Abstract: | A novel bacterial strain was isolated and identified as Bacillus pumilus, with the capability to produce cholesterol oxidase enzyme (55?kDa). The production of the enzyme was optimized via two-step statistical approach. Out of eight factors screened in Plackett–Burman, only four had significant effects on enzyme activity. The optimization process of these four variables by Box–Behnken revealed that the maximum enzyme activity (90?U/mL) was significantly obtained after 6 days of fermentation with 0.3%, 1% and 0.2% of NH4NO3, yeast extract and Tween 80, respectively. The purified enzyme showed optimum activity at pH 7.5 and temperature of 40?°C. The enzyme retained 100% of its activity after storage at 40?°C for 60?min. The enzyme also exhibited enhanced stability in the presence of Tween 80, methanol and isopropanol. This solvent and thermal stress tolerant enzyme, produced by B. pumilus, may provide a practical option for industrial and analytical applications. |
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Keywords: | Bacillus cholesterol oxidase optimization purification kinetics |
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