Bioemulsifier production by newly isolated Pseudomonas aeruginosa AM02 using soybean oil as sole carbon source

In recent years use of bioemulsifier (biosurfactants) are increasing due to global environmental awareness. It is due to low/non toxicity, biodegradability and activity at the extreme industrial conditions compared to their chemical surfactants. This study focused on isolation and characterization of high potential bioemulsifier bacterial strains from different wastewater of food industries as well as fresh and spoiled foods. Kinetic of bioemulsifier production using soybean oil as sole carbon source was studied. Among 800 different colonies, a high producing bacterium, which was isolated from sugar beet molasses, was selected for further studies. It was identified as Pseudomonas aeruginosa AM02 by morphological and biochemical methods as well as 16S rRNA gene sequencing. It could produce more than 12 g/l bioemulsifier using soybean oil as sole carbon source. Critical micelle concentration of purified bioemulsifier was 27.5 mg/l with surface tension of 30.6 mN/m. Foaming ability of bioemulsifier was considerable (120%) and it emulsified corn, soybean and coconut oils more than 50%. Emulsification index for hydrocarbons (hexane, crude oil, brake oil, xylene, kerosene, mineral oil and hexadecane) was 50.9-93%. It had high stability at different pH values, temperatures and ionic strengths. These results suggested potential applications of AM02 bioemulsifier in enhanced oil recovery, bioremediation, food and cosmetic industries. Moreover, residual from edible oil processing industries can be used as a cheap substrate for economic production of bioemulsifier by AM02 strain.