Production and formulation of a new low-cost biosurfactant to remediate oil-contaminated seawater

• Published in: Journal of biotechnology 2019-04, Vol.295, p.71-79
• Main Authors: Ostendorf, Thaís A., Silva, Ivison A., Converti, Attilio, Sarubbo, Leonie A.
• Format: Article
• Language: English
• Subjects: Agro-industrial waste; Bacillus; Bacillus - metabolism; Biodegradation, Environmental; Biosurfactant; Burkholderia cepacia - metabolism; Environmental contamination; Oil and Gas Industry; Petroleum; Petroleum - analysis; Pseudomonas; Seawater - chemistry; Surface-Active Agents - chemistry; Surface-Active Agents - metabolism; Water Pollutants, Chemical - chemistry; Water Pollutants, Chemical - isolation & purification; Water Pollutants, Chemical - metabolism
• ISSN: 0168-1656; 1873-4863
• DOI: 10.1016/j.jbiotec.2019.01.025

•Biosurfactants were produced by three bacterial strains.•Bacillus cereus grown in industrial wastes was the best biosurfactant producer.•The biomolecule is a lipopeptide with surface tension of 26 mN/m and low toxicity.•High removal rates of oil adsorbed to rock and dispersion in seawater were obtained.•The formulated biosurfactant can be successfully applied in the petroleum industry. The aim of the present study was to produce biosurfactants using three bacterial strains (Pseudomonas cepacia CCT6659, Bacillus methylotrophicus UCP 1616 and Bacillus cereus UCP 1615) cultivated in mineral medium containing different carbon (glucose, sucrose, molasses and waste frying oil) and nitrogen [NH4NO3, (NH4)2SO4, peptone, yeast extract and corn steep liquor] sources. B. cereus stood out as the best biosurfactant producer when inoculated with a 1.5% cell suspension and cultivated at 28 °C and 200 rpm in 2.0% molasses and 1.0% corn steep liquor for 48 h. Under these conditions, medium surface tension was reduced to 26.2 ± 0.2 mN/m, and biosurfactant concentration achieved 2.05 ± 0.32 g/L. The biosurfactant showed a critical micelle concentration of 0.90 ± 0.05 g/L, proved to be highly stable in wide ranges of pH, salt concentration and heating temperature, and exerted low toxicity to larvae of Artemia salina as a marine environmental bioindicator. Structural characterisation of biosurfactant suggested a lipopeptide composition. The biotensioactive agent was shown to effectively remove motor oil adsorbed to marine rock (91.0 ± 0.4%) and to disperse it in seawater (70.0 ± 0.4%). The biosurfactant formulated with 0.2% potassium sorbate demonstrated considerable potential for application in the petroleum industry, where it could be successfully used as a commercial product to mobilize oil in marine environments.