Abstract:
Palm oil is one of the most widely consumed edible oils today. Apart from using as cooking oil, palm oil is also used in many processed foods industries. Because of its hydrophobicity, palm oil could cause severe problems in wastewater treatment system for example wastewater pipe clogging. Previous studies found that microorganism that produced extracellular lipase could degrade oil effectively and can be used in wastewater treatment. Thus, the objective of this study was to construct microbial consortium for palm oil degradation in synthetic wastewater using continuous process. Seven yeast isolated strains and three bacteria isolated strains showed high palm oil degradation (%) when incubated into 50 ml. synthetic wastewater medium containing 1% (w/v) palm oil at 30oC and 200 rpm for 72 h. Among these isolated strains, Candida sp. CBS 10854 showed the highest palm oil degradation (98.22%) and the highest lipase activity (1.639 ± 0.07 Unit/ml). For the application of oil-containing wastewater treatment, Palm oil degradation by yeast consortium, bacteria consortium and microbial consortium were investigated in continuous cultivation system. The results showed that microbial consortium had the highest palm oil degradation compared to that of yeast consortium and bacteria consortium. The mean of palm oil degradation rate was 90.50 ± 3.53 %. Moreover, microbial consortium had the highest lipase activity as showed in the mean of lipase activity in continuous stirred reactor (3.003 ± 0.08 Unit/ml). Inaddition, the microbial dynamics of microbial consortium during 168 h in continuous cultivation system were investigated using Denaturing gradient gel electrophoresis technique. The results showed that Candida sp.CBS 10854, Candida tropicalis strain Vaucher, Yarrowia lipolytica, Bacillus subtilis subsp. subtilis strain E28 and Bacillus subtilis subsp. subtilis strain A17 were the dominant strains and remained throughout in continuous cultivation system.