Biosurfactants from marine bacterial isolates

Biosurfactants are extracellular surface active compounds produced by bacteria, fungi and yeast. Most microbial surfactants are complex molecules, comprising different structures that include lipopeptides, glycolipids, polysaccharide protein complexes, fatty acids and phospholipids. In the past two decades, biosurfactants have gained increasing attention due to their useful properties such as biodegradability, low toxicity, ecological acceptability and ability to be produced from renewable and cheaper substrates. The range of industrial applications of biosurfactants includes enhanced oil recovery, crude oil drilling, lubricants, and bioremediation of environmental pollutants, health care, food processing, medical applications as adjuvants and as antimicrobial biocontrol agents. In this chapter we report on an investigation to explore biosurfactant producing marine bacteria. The main criteria used for the isolation of biosurfactants producers were hemolytic assay, bacterial adherence to hydrocarbons (BATH), emulsification of crude oil and the drop-collapse test. Bacterial strains were isolated and subjected to screening tests for biosurfactants production. 3 bacterial strains were found as potential biosurfactant producers and identified as Bacillus megaterium, Corynebacterium kutscheri and Pseudomonas aeruginosa. Crude oil was used as a carbon source for biosurfactant production in shake flask fermentation experiments to optimize the culture conditions. Fermentor production of biosurfactant was carried out with economically cheap or sustainable carbon sources such as waste motor lubricant oil and peanut oil cake. Preliminary characterization of biosurfactant products for isolated B. megaterium, C. kutscheri and P. aeruginosa were glycolipid, glycolipopetide and lipopeptide respectively.