Enzymatic pre-hydrolysis of high fat content dairy wastewater as a pretreatment for anaerobic digestion

Enzymatic extract preparation from Psendomonas 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 45[ae%] 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 Upases

Isolation and identification of a novel, lipase-producing bacterium, Pseudomnas aeruginosa KM110

Lipases are particularly important due to the fact that they specifically hydrolyze acyl glycerol, oils and greases, which is of great interest for different industrial applications. In this study, several lipase-producing bacteria were isolated from wastewater of an oil processing plant. The strain possessing the highest lipase activity was identified both biochemically and sequencing of 16S rRNA gene. Then we increase lipase activity by improving conditions of production medium. Also, lipase from this strain was preliminarily characterized for use in industrial application. The 16S rRNA sequensing revealed it as a new strain of Pseudomonas aeruginosa and the type strain was KM110. An overall 3-fold enhanced lipase production [0.76 U mL[-1]] was achieved after improving conditions of production medium. The olive oil and peptone was found to be the most suitable substrate for maximum enzyme production. Also the enzyme exhibited maximum lipolytic activity at 45°C where it was also stably maintained. At pH 8.0, the lipase had the highest stability but no activity. It was active over a pH range of 7.0-10.0. The lipase activity was inhibited by Zn[2+] and Cu[2+] [32 and 27%, respectively] at ImM. The enzyme lost 29% of its initial activity in 1.0% SDS concentration, whereas, Triton X-100, Tween-80 and DMSO did not significantly inhibit lipase activity. Based on the findings of present study, lipase of P. aeruginosa KM110 is a potential alkaline lipase and a candidate for industrial applications such as detergent, leather and fine chemical industries