Sustainable synthesis of pectinolytic enzymes from citrus and Musa acuminata peels for biochemical oxygen demand and grease removal by batch protocol

Abstract

In recent years, oil and grease has been identified as an emerging pollutant of concern (EPC) in wastewater stream as it can disturb the ecology and wastewater treatment process efficiency. The highest contributor to oily wastewater among domestic wastewater is from kitchen greywater. One of the alternatives to address this problem is the application of enzyme. The production of enzyme by using organic waste has gained significant attention in the recent years due to sustainable demand from it. In this study, pectinolytic enzyme was produced through simplified fermentation from discarded citrus peels that possess high lipase content. Three batches of treatment which consist of the control sample (solely wastewater), 25% (v/v) citrus enzyme + wastewater and 50% (v/v) citrus enzyme + wastewater was incubated in an incubator shaker for 10 days at 30 °C and 150 rpm. The wastewater analysis was performed at a regular interval of 48 h. The parameters monitored were pH, BOD5 and oil and grease. Laboratory work has demonstrated that 25% (v/v) pectinolytic enzyme was able to remove BOD5 and oil and grease about 10% better than 50% (v/v) pectinolytic enzyme. The percentage of removal achieved by 25% (v/v) pectinolytic enzyme was 39.83 ± 9.50 mg/L and 64.21 ± 1.12 mg/L, respectively. However, it was observed that enzyme was less effective in removing BOD5 as the solution contains organic matter that increases the total organic matter in the wastewater mixture.