ABSTRACT
Surfactants produced from microorganisms, also known as biosurfactants, are amphiphilic molecules that help in reducing interfacial tension between fluid phases. In recent years, there has been an increased interest in the study of microbial surfactants, as these biomolecules find wide domestic, industrial and environmental applications as lubricants, detergents, pesticides, and agents for enhanced oil recovery and hydrocarbon remediation. Non-renewable energy resources like petroleum hydrocarbons are major environmental pollutants, posing a threat to terrestrial and marine life. Microbial surfactants are able to adhere, assimilate and degrade hydrocarbons that can cause damage to ecosystems and, therefore, are considered as suitable eco-friendly alternatives for remediation processes. Such biosurfactants produced by different bacteria and fungi, as extracellular materials or as components of their cell membranes, are advantageous because they have unique physico-chemical properties, low toxicity, high biodegradability and environmental compatibility as compared to chemical surfactants. They also display multi-functionality with the ability to function under varying conditions of temperature, pH and salinity. This review provides a comprehensive report on biosurfactants, including their structural diversity, classification, screening of microbial producers, assay methods, physico-chemical factors of biosynthesis and diverse applications along with emphases on their role in bioremediation.
