Microbial surfactants are green molecules with high surface activities having the most promising advantages over chemical surfactants including their ability to efficiently reducing surface and interfacial tension, nontoxic emulsion-based formulations, biocompatibility, biodegradability, simplicity of preparation from low cost materials such as residual by-products and renewable resources at large scales, effectiveness and stabilization under extreme conditions and broad spectrum antagonism of pathogens to be part of the biocontrol strategy. Thus, biosurfactants are universal tools of great current interest. The present work describes the major types and microbial origin of surfactants and their production optimization from agro-industrial wastes in the batch shake-flasks and bioreactor systems through solid-state and submerged fermentation industries. Various downstream strategies that had been developed to extract and purify biosurfactants are discussed. Further, the physicochemical properties and functional characteristics of biosurfactants open new future prospects for the development of efficient and eco-friendly commercially successful biotechnological product compounds with diverse potential applications in environment, industry, biomedicine, nanotechnology and energy-saving technology as well.
Keywords: Microbial surfactants; SSF and SmF processes; agro-industrial wastes; environmental and industrial applications; productivity optimization.
HighlightsBiosurfactants are important biotechnological products with unique superior potentials over their synthetic counterparts.Physiological roles of biosurfactants in survival of the producing microorganisms under unfavorable conditions.Classification of biosurfactants.Biosurfactant types produced by yeasts, fungi and bacteria.Production efficiency optimization of biosurfactants.Utilization of agro-industrial wastes as economic renewable substrates for biosurfactants production.Production of biosurfactants by solid-state and submerged fermentation industries.Potential applications of biosurfactants in environment.Glycolipid biosurfactants efficiently control pathogens causing their membrane disruption.Potential application of biosurfactants in the oil industry.Natural surfactants are novel capping and stabilizing agents for nanoparticles synthesis.