Treatment of lipid-rich wastewater using a mixture of free or immobilized bioemulsifier and hydrolytic enzymes from indigenous bacterial isolates

The combined use of free or immobilized bioemulsifier produced by Acinetobacter sp. and enzyme pool (protease and lipase) from Bacillus aryabhattai in the reduction of organic pollutants present in lipid-rich wastewater was investigated. Physicochemical characterization of the raw wastewater revealed high pollutant load in poultry processing wastewater in comparison to dairy wastewater. Biodegradability of the wastewater was assessed by measuring the reduction of COD and lipid contents at time intervals under varying process conditions. In dairy wastewater treated at 37°C without pH adjustment, maximum COD (61 and 65%) and lipid (48 and 64%) reduction efficiencies were recorded at 120 h using free and immobilized bioproducts, respectively. However, under these conditions, maximum COD (86 and 94%) and lipid (52 and 69%) removal efficiencies of poultry processing wastewater were observed at 120 h when treated with free and immobilized bioproducts, respectively. At temperature of 50°C and pH 8.0, there was enhanced reduction of organic pollutants, with maximum COD (66 and 78%) and lipid (55 and 71%) removal efficiencies obtained in dairy wastewater at 72 h when using free and immobilized bioproducts, respectively. In the case of poultry processing wastewater, optimum COD (90 and 95%) and lipid (63 and 77%) removal was recorded at 72 h when treated with free and immobilized bioproducts, respectively. Reusability studies suggest that the immobilized bioproducts could be reused for up to six and seven times for the treatment of dairy and poultry processing wastewater, respectively. This study suggests the efficient and synergistic application of the developed immobilized bioemulsifier and hydrolytic enzymes in the treatment of high fat-containing wastewater.