This study investigates the production of alkane hydroxylase, lipase and esterase by the marine hydrocarbon degrading bacteria Alcanivorax borkumensis. The focus of this study is the remediation of petroleum hydrocarbons, hexane, hexadecane and motor oil as model substrates. A. borkumensis showed an incremental growth on these substrates with a high cell count. Growth on motor oil showed highest alkane hydroxylase and lipase production of 2.62 U/ml and 71 U/ml, respectively, while growth on hexadecane showed the highest esterase production of 57.5 U/ml. The percentage of hexane, hexadecane, and motor oil degradation during A. borkumensis growth after 72 h, was around 80%, 81.5% and 75%, respectively. Zymogram showed two different bands with a molecular weight of approx. 52 and 40 kDa, respectively with lipase and esterase activity. Alkane hydroxylase reached optimum activity at pH 8.0 and 70 ± 1 °C for hexane and hexadecane and 75 ± 1 °C for motor oil. Lipase and esterase showed optimum activity at 35 ± 1 °C and 40 ± 1 °C, respectively and pH 7.0. The crude enzymes showed higher stability in a wide range of pH, but they were not thermostable at higher temperatures.
Keywords: Alcanivorax borkumensis; Alkane hydroxylase; Biodegradation; Esterase; Lipase; Petroleum hydrocarbons.
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