Isolation and characterization of lipid-degrading bacteria in wastewater of food processing plants and restaurants in Can Tho city, Vietnam

Abstract

High lipid (fats and oils) concentration contained in wastewater inhibits the activity of microbes in biological wastewater treatment systems. The lipids degradation capability of lipid-degrading bacteria was investigated for possible application in treatment of lipids-contaminated wastewater. One hundred and two bacterial isolates were isolated from 43 vegetable oil- contaminated wastewater samples of many food processing plants and restaurants in 5 districts of Can Tho city, Vietnam on LB medium. There were sixty-one isolatesproduced clear zones on Tw20 medium, only eleven of which were found to have the high ability to degrade vegetable oil in the contaminated wastewater. These eleven isolates were identified by PCR technique and DNA sequencing. The results of DNA sequencing were compared with GenBank database of NCBI by BLAT N software. The sequences from selected isolates showed high degrees of similarity to those of the GenBank references (between 97% and 99%). Two isolates belonged to Bacilli (18.18%) and nine isolates belonged to Gammaproteobacteria (81.82%). Based on Pi value (nucleotide diversity), Gammaproteobacteria group had the highest Theta values. Theta value (per sequence) from S of SNP for DNA polymorphism were calculated for each group and 11 strains of lipid-degrading bacteria had high genetic diversity. The results propose Acinetobacteria solistrain AL3 a potential bioproduct for wastewater treatment because of its high ability of lipid degradation and biosafety.