Biosurfactants

Abstract

Biosurfactants are amphiphilic compounds produced by microorganisms. They have high surface activity and low critical micelle concentrations (cmc), and therefore are promising substitutes for synthesized surfactants. Biosurfactants have several advantages over synthetic surfactants, including lower toxicity, higher biodegradability, better environmental compatibility, higher foaming in processes and applications requiring high foam, and high selectivity and specific activity at extreme temperatures, pH, and salinity. Furthermore, biosurfactants can be produced from agro-industrial waste as starting materials, which helps to reduce overall production costs. Biosurfactants are classified into high-MW (molecular weight) and low-MW biosurfactants. Low-MW biosurfactants include glycolipids, lipopeptides, and phospholipids, whereas high-mass surfactants include polymeric and small molecules surfactants. Biosurfactants can be used as emulsifiers, de-emulsifiers, wetting agents, spreading agents, foaming agents, functional food ingredients, and detergents. Biosurfactants are used in various industries such as petroleum and petrochemicals, organic chemicals and polymers, foods and beverages, cosmetics and pharmaceuticals, mining and metallurgy, agrochemicals and fertilizers, environmental control and management, and many others. This chapter deals with biosurfactants and their applications in tribology, the petroleum industry, and environmental remediation. The tribological applications of biosurfactants reported here include anticorrosion, antimicrobial, and emulsification processes.