Enzymatic Pre-Hydrolysis of high fat Content Dairy Wastewater as a Pretreatment for Anaerobic Digestion

Abstract

Enzymatic extract preparation from Pseudomonas aeruginosa KM110 under accession No. HQ730879 with lipase activity (0.3 U/ml), was used to perform enzymatic hydrolysis pretreatment of a synthetic dairy wastewater with 1000 mg/L total fat content. The pretreatment was optimized for 48 h hydrolysis time, at 45æ% C with 10% v/v enzymatic extract. The biological treatment of synthetic dairy wastewater was investigated using a batch bioreactor. Both raw and prehydrolyzed wastewater was digested in a batch bioreactor. Enhanced anaerobic digestion efficiency compare to raw wastewater was achieved (chemical oxygen demand (COD), removal efficiency of 90% vs. 66% and biogas production of 4710 ml vs. 2330 ml after 13days). The results obtained in this study illustrated that the application of a pretreatment process to hydrolyze and dissolve fats may improve the biological degradation of fatty wastewaters, accelerating the process and reducing time of anaerobic digestion. Moreover, the pretreatment of wastewater from several sources is a new and promising application for lipases.