Performance of a biosurfactant produced by a Bacillus subtilis strain isolated from crude oil samples as compared to commercial chemical surfactants

• Published in: Colloids and surfaces, B, Biointerfaces Vol. 89; no. 1; pp. 167 - 174
• Main Authors: Vaz, Deisi Altmajer, Gudiña, Eduardo J., Alameda, Encarnación Jurado, Teixeira, José A., Rodrigues, Lígia R.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.01.2012
• Subjects: Alkylbenzene; Bacillus; Bacillus subtilis; Bacillus subtilis - metabolism; Bacillus subtilis - physiology; Bacterial Adhesion; Biomass; Biosurfactants; colloids; Crude oil; emulsifying; Emulsions; Escherichia coli; Findet®1214N/23; Glucopone®215; Glucopone®650; hexadecane; Hydrogen-Ion Concentration; industry; Kinetics; LAS; Micelles; Oils - metabolism; petroleum; Petroleum - metabolism; Special effects; Staphylococcus aureus; Sulfonates; Surface Properties; surface tension; Surface-Active Agents - metabolism; Surfactants; surfactin; temperature; Findet®1214N/23; Glucopone®650; Bacillus subtilis; Biosurfactants; Glucopone®215; LAS
• ISSN: 0927-7765; 1873-4367
• DOI: 10.1016/j.colsurfb.2011.09.009

. Time course of growth and biosurfactant production in LB medium by Bacillus subtilis EG1 isolated from crude oil samples. [Display omitted] ► A biosurfactant produced by a Bacillus subtilis strain was characterized and compared with chemical surfactants. ► The biosurfactant was found to be as stable as the commercial chemical surfactants to temperature changes. ► It showed equal or higher emulsifying activity as compared to the chemical surfactants. ► Also, the anti-adhesive activity was higher than the commercial chemical surfactants. ► This biosurfactant constitutes an interesting alternative to the commercial chemical surfactants with potential use in several industries. In this work, the biosurfactant produced by a Bacillus subtilis strain isolated from crude oil samples was characterized and its properties compared with commercially available chemical surfactants. The purified biosurfactant production yield (YP/X) was 0.20g/gcell dry weight. The surface tension (29.0mN/m) and critical micelle concentration (40mg/l) were found to be similar to the values previously reported for surfactin. Temperature and pH stability of the biosurfactant were also evaluated. The biosurfactant was exposed to different temperatures (20, 37 and 46°C) during two weeks and was found to be as stable as the commercial chemical surfactants Glucopone®215, Glucopone®650, Findet®1214N/23 and linear alkylbenzene sulfonates (LAS). Moreover, the biosurfactant subjected to 121°C for 20min did not exhibit a significant loss of surface activity. Contrary to the commercial chemical surfactants that were found to be stable over a wide range of pH (3.0–10.0), the biosurfactant was unstable precipitating at pH values below 5.0. The emulsification indexes showed that the biosurfactant possesses equal or superior capacity to form emulsions with n-hexadecane as compared to the commercial chemical surfactants. Moreover, the anti-adhesive activity of the biosurfactant and commercial chemical surfactants was evaluated. The biosurfactant showed some activity against Staphylococcus aureus and Escherichia coli. Nevertheless, no particular trend or special effect could be assigned to the use of commercial chemical surfactants as anti-adhesives. Results gathered in this work suggest that the biosurfactant recovered from B. subtilis EG1 constitutes an interesting alternative to the commercial chemical surfactants with potential use in several industries.