Lipase-Producing Microorganisms for Use in Contaminated Fat and Oil Kitchen Wastewater Treatment

Abstract

                Biodegradation of fats and oils in wastewater has a potential role in pollution control. Then, selection of efficient microorganisms for degrading fats and oils in laboratory level has been investigated by using single culture of Acinetobacter sp. (KUL8), Bacillus sp. (KUL39) and Pseudomonas sp. (KLB1) and mixed cultures of Acinetobacter sp. (KUL8) and Pseudomonas sp. (KLB1). The result showed that single culture of Pseudomonas sp. (KLB1) and mixed cultures of Acinetobacter sp. (KUL8), Bacillus sp. (KUL39) and Pseudomonas sp. (KLB1) could be reduced fat and oil content by 55.91% and 60.42%, respectively. These cultures were shown highest efficiency activities. Thus, these cultures were selected to study speed of shaking and inoculum size in wastewater treatment, which it was found that the efficiency of fat and COD degradation were highest reduced at 250 rpm of speed of shaking. Inoculum size at 1-2.5 % and 5 % of single culture and mixed cultures could remove fat and oil by 61.78-65.19 % and 60.42 %, respectively. And initial COD concentration at 4,000 mg/l has the highest efficiency 83.46% and 95.81% in fat and COD degradation, respectively.

                 The last experiment, Pseudomonas sp. (KLB1) was used in occasionally influent and effluent contaminated fat and oil kitchen wastewater treatment in reactor. The results showed that the highest efficiency of aerobe conditions were 50.02% and 0.76 U/ml, respectively in fat degradation and lipase activity after adding 8% of single culture at 22 days. After that lipase activity was reduced because influent and effluent of wastewater in reactor depended on activity of kitchen. Since dilution rates (D) of wastewater in reactor were higher than specific growth rate (μ), so microorganisms were washed out. Thus, the immobilization of microorganism cells on plastic balls has been used. The results showed that cells immobilization could increase efficiency of wastewater treatment in reactor.