A Review on Biosurfactants: Fermentation, Current Developments and Perspectives

Surfactants are compounds that reduce the surface tension of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid. Surfactants are characteristically organic compounds containing both hydrophobic groups (their tails) and hydrophilic groups (their heads). Therefore, a surfactant molecule contains both a water insoluble (and oil soluble component) and a water soluble component. Biosurfactants encompass the properties of dropping surface tension, stabilizing emulsions, promoting foaming and are usually non-toxic and biodegradable. Interest in microbial surfactants has been progressively escalating in recent years due to their diversity, environmentally friendly nature, possibility of large-scale production, selectivity, performance under intense circumstances and their impending applications in environmental fortification. These molecules have a potential to be used in a variety of industries like cosmetics, pharmaceuticals, humectants, food preservatives and detergents. Presently the production of biosurfactants is highly expensive due to the use of synthetic culture media. Therefore, greater emphasis is being laid on procurement of various cheap agro-industrial substrates including vegetable oils, distillery and dairy wastes, soya molasses, animal fat, waste and starchy waste as raw materials. These wastes can be used as substrates for large-scale production of biosurfactants with advanced technology which is the matter of future research. This review article represents an exhaustive evaluation of the raw materials, with respect to their commercial production, fermentation mechanisms, current developments and future perspectives of a variety of approaches of biosurfactant production.