Evaluation of biosurfactant production potential of Lysinibacillus fusiformis MK559526 isolated from automobile-mechanic-workshop soil.

BACKGROUND: Biosurfactants are amphipathic biological compounds with surface active potential and are produced by many microorganisms. Biosurfactant production by Lysinibacillus fusiformis MK559526 isolated from automobile-mechanic-shop soil was investigated with a view to assessing its potential for production and potential for optimization.
MATERIALS AND METHODS: Effects of carbon and nitrogen sources, pH, temperature and incubation periods on biosurfactant production were evaluated with a view to optimizing the processes. Fourier Transform Infra-Red absorption peaks and Gas chromatography mass spectrometry were used to determine the functional groups of the chemical make-up and the chemical profile of the biosurfactant respectively.
RESULTS: Lysinibacillus fusiformis surfactant had emulsification index of 65.15 ± 0.35 %, oil displacement of 2.7 ± 0.26 mm, zone of haemolysis of 7.3 ± 0.16 mm and a positive drop collapse test. Optimized culture conditions for biosurfactant production: temperature, 35 ºC; pH, 7.0; starch solution, 40 g/L and urea, 1.5 g/L showed a reduction in surface tension to 28.46 ± 1.11 mN/m and increased emulsification index to 93.80 ± 0.41 %. Maximum biosurfactant production of 2.92 ± 0.04 g/L was obtained after 72 h. The biosurfactant contained peptides and fatty acids. The predominant fatty acid was 9-Octadecenoic acid (80.80%).
CONCLUSIONS: The above results showing high emulsification potential and remarkable reduction in the surface tension are good biosurfactant attributes. Consequently, Lysinibacillus fusiformis MK559526 is a good candidate for biosurfactant production.