Isolation and identification of lipid-degrading yeast from wastewater of canteens and restaurants in Ninh Kieu district, Can Tho city

Abstract

High lipid (fats and oils) concentration contained in wastewater from restaurants and canteens released into environment directly, leading to be pollutant water and logging drainpipe systems. The lipid-degradation capability of lipid-degrading yeast was investigated for possible application in treatment of lipids-contaminated wastewater. Twenty-eight yeast isolates were isolated from 11 lipid-contaminated wastewater samples from many restaurants and canteens in Ninh Kieu district of Can Tho city, Vietnam. There were 15 isolates produced halo zones on Tw20 agar medium and determined to have ability of lipid-degradation, three of which (B1, ST, Da2a isolates) were found to have the high ability of lipid-degradation by measuring development of halo zone diameter during 72 hours and identified by ITS-PCR technique and DNA sequencing. After 7 days of cultivation, the rate of the degradation of lipid contaminated in wastewater by strain B1, ST, Da2a were 74.14%, 83.03% and 80.7%, respectively. The results of DNA sequencing were compared with GenBank database of NCBI by BLAST N software. The sequences from selected isolates showed high degrees of similarity to those of the GenBank references (between 97% and 99%). Isolates of B1 and ST were 99% of similarity with Candida palmioleophila and Meyerozyma quilliermondii, respectively. Da2a isolate was 97% of similarity with Candida tropicalis.Keywords: Candida, canteens and restaurants, lipid-contanminated wastewater, lipid-degradation yeast, lipid degradion, vegetable oil