ABSTRACT

    The local isolate TY10 was derived from a soil sample that was polluted with oil in a previous investigation. The study focused on evaluating the isolate’s capacity to manufacture the laccase enzyme. The Bacillus cereus isolate was identified based on the findings of morphological and biochemical testing, as well as the VITEK-2 tests. The synthesis of laccase by the Bacillus cereus TY10 isolate was assessed using qualitative and quantitative methods, with guaiacol serving as a substrate indicator. The qualitative investigation revealed that the local isolate TY10 exhibited a strong capacity for laccase enzyme production in the solid medium. Simultaneously, it was shown that the indigenous strain Bacillus cereus TY10 exhibited an enzyme activity of 0.98 units/ml when the broth of the indigenous strain was utilised in quantitative measurements for enzyme synthesis. The impact of different durations of incubation, pH values, and the current research focused on examining temperatures and their impact on the ability of a local entity Bacillus cereus TY10 Extract laccase enzyme by isolation. The study discovered that laccase production reached its peak of 1.61 Unit/ml occurred after 48 hours of incubation at 35°C, using a growth medium with a pH of 7. The crude laccase enzyme underwent a purification procedure consisting of three sequential steps: Ammonium sulphate precipitation and two gel filtration steps using Sephadex G-25 and G-100. This process resulted in a 6.52 times purification of the laccase enzyme, with a recovery rate of 90.65% and a specific activity of 39.98 unit/mg protein. All purification steps contributed to this outcome.