Preliminary investigations into the utilization of lipase cross-linked enzyme aggregates (CLEA) in the hydrolysis of lipid-rich wastewater

Abstract This study utilized Rhizopus oryzae lipase (RoL) as a potential biocatalyst in the hydrolysis of oil-contaminated wastewater. Immobilization of the RoL occurred via the preparation of cross-linked enzyme aggregates of the RoL using ammonium sulphate (50% w/v) and glutaraldehyde (0.125% v/v) as the precipitant and cross-linker respectively. Characterization of the RoL-CLEA was carried out using scanning electron microscopy. Prior to the enzymatic treatment of the wastewater, the lipid concentration and the chemical oxygen demand levels were determined. The RoL-CLEA could be reused up to five cycles and its catalysis increased free fatty acid levels in the wastewater by 84.8% and 142.1% at 0.5% and 1% (w/v) CLEA respectively. There was an increase in chemical oxygen demand (COD) removal by 7.6% and 29.5% from the oil-contaminated wastewater when 0.5% (w/v) and 1% (w/v) of the immobilized biocatalyst was used. In conclusion, the RoL CLEA is a unique biocatalyst in the treatment of oil-contaminated wastewater. Hence, there is the possibility of utilizing this biocatalyst for the large-scale remediation of oil-contaminated water bodies.