Abstract:
In this study, optimization conditions for lipase production from Candida rugosa in submerged culture were investigated. It was found that optimal medium consisted of cotton seed oil 3% (w/v), molasses 0.1% (w/v) and yeast extract 1.5% (w/v). After cultivation at 25°C, pH 7.0 for 120 hours, the maximum lipase activity of 22.74 U/ml using p-nitrophenyl butyrate as a substrate for lipase assay was obtained. This research could improve lipase production about 7.3 folds higher than original condition. Partial characterization of crude lipase was determined. The enzyme showed the maximum activity at pH 7.0 and the pH stability was pH 7.0 with 89% residual activity. The lipase had an optimal temperature at 40°C and thermal stability was 30°C with 50% residual activity after 24 hours of incubation. Crude lipase at the concentrations of 2.5-20% (v/v) was used to degrade 1 % (w/v) of palm oil in synthetic wastewater. The pretreatment became evident when the wastewater was treated with 7.5% (v/v) lipase. Percent triglyceride removal reached 99.17% within 24 hours at 30°C. The hydrolysis of triglyceride was then tested with a wastewater from palm oil mill. The result showed that palm oil was completely hydrolyzed within 24 hours by using 7.5% (v/v) of crude lipase and COD removal was found to be 80.81% after 14 days. The results obtained indicate that the potential of lipase which is an effective alternative for the treatment of wastewater containing oil such as wastewater generated from palm oil mill