Demulsifying properties of extracellular products and cells of Pseudomonas aeruginosa MSJ isolated from petroleum-contaminated soil

• Published in: Bioresource technology 2013-01, Vol.128, p.646-654
• Main Authors: Coutinho, J.O.P.A., Silva, M.P.S., Moraes, P.M., Monteiro, A.S., Barcelos, J.C.C., Siqueira, E.P., Santos, V.L.
• Format: Article
• Language: English
• Subjects: Biodegradation, Environmental; Biological and medical sciences; Cellular; Culture; Demulsification; Diesel; Emulsions; Emulsions - chemistry; Emulsions - metabolism; Fatty acids; Fundamental and applied biological sciences. Psychology; Hydrophobicity; Industrial Oils - microbiology; Oil-in-water emulsions; Pseudomonas aeruginosa; Pseudomonas aeruginosa - classification; Pseudomonas aeruginosa - metabolism; Soil Microbiology; Soil Pollutants - chemistry; Soil Pollutants - isolation & purification; Species Specificity; Waste water; Water-in-oil emulsions
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2012.09.137

[Display omitted] ► Cells and supernatant of Pseudomonas aeruginosa cultures showed emulsifying activity. ► Demulsifying activity was relatively stable in different physicochemical conditions. ► The extracellular biodemulsifier is composed of fatty acids and carbohydrates. ► The demulsifier was active against industrial emulsions with oil Daido Dairoll PA-5A. ► Demulsification varied according to growth media, culture age and cell hydrophobicity. A strain of Pseudomonas aeruginosa isolated from a site contaminated with refined oil products exhibited demulsification capabilities against Tween 80–Span 80 stabilized oil-in-water (O/W), Tween 80-stabilized water-in-oil (W/O) model emulsions (kerosene–water), and an industrial emulsion (Daido Dairoll PA-5A). GC–MS analysis confirmed the presence of fatty acids and carbohydrates in the extracellular biodemulsifier. The demulsifying activity of cells and culture supernatants was favored by growth in media containing 1% diesel oil. There was a correlation between culture age, de-emulsification and cellular hydrophobicity, and highest activities were observed for cells and supernatants from 96-h cultures. Activity increased with addition of up to 60mg cells or 300μL supernatant to emulsions. The activity was relatively stable at 20–40°C and to freezing, but was reduced by 69% by washing the cells with chloroform–methanol-water. This demulsifier has potential for application in biotreatment of emulsified oily wastewaters to promote recovery and/or degradation of oil.