Abstract:
The aim of this research was to study biological treatment of fat, oil, and grease in wastewater by yeast. Real wastewater from canned fish industry that has fat, oil, and protein as its component was used in this experiment. The results of wastewater analysis showed COD value of 3,680 mg/L, lipid and oil of 2,822 mg/L, protein of 714 mg/L and total carbon of 1,146 mg/L. Three yeast strains used in this research were pure culture that had been undergone enzyme lipase primary production test as Candida maltosa, Candida tropicalis and Yarrowia lipolytica. After cultivation in wastewater at room temperature with rotational speed at 200 rpm for 48 hours, the COD removal efficiency was found to be 85.57, 82.09 and 95.73 percent for Candida maltosa, Candida tropicalis and Yarrowia lipolytica respectively, and the removal efficiency of oil and fat equaled to 53.74, 51.07 and 82.74 percent, respectively. Consequently, it could be concluded that Yarrowia lipolytica had the highest capability in fat and oil removal from oily wastewater. Moreover, Yarrowia lipolytica biomass contained all the essential amino acids which were well balanced and surpassed well with the Food Agricultural Organization (FAO) guideline. Its high content of the essential amino acids suggested that the yeast protein would be suitable as the protein supplement to increase the protein quality of animal feed. The kinetics of organic utilization using Haldanes equation was calculated. The maximum specific growth rate (µm), half - saturation coefficient (KS) and inhibition constant (Ki) were 0.37 hr-1, 434 mg/l and 489 mg/l, respectively. These values are comparable with those that have been reported by all review literatures, suggesting that those kinetic values may be suitable for oily wastewater treatment plant design