Biosurfactants of Nitrogen Fixers and their Potential Applications

Rising agricultural productivity is a matter of great concern globally, to meet the ever increasing food demands of human population. Numerous areas of agriculture use surfactants, like in crop protection and agrochemical formulations. The use of hydrocarbons has resulted in widespread environmental pollution. It is important to clean up contaminated sites because of their toxicity, persistent and negative effects on living organisms. Majority of surfactants produced at present are chemically derived from petroleum. These surfactants present in formulations of pesticides get deposited in soil and affects plant's texture, colour and growth. These toxic pesticides are also leached from the soil to the ground water. Consequently, by physico-chemical procedures, the hydrocarbon pollutants show moderate to low recovery; minimal bioavailability to microorganisms; and limited availability when applied to in-situ and/or ex-situ applications of oxidative and reductive chemicals. Chemically generated surfactants have gradually been replaced by bio-based products obtained either from plant sources or microbial sources. Surface active biomolecules produced by microorganisms are known as biosurfactants. They mark features such as emulsification, foaming, detergency and dispersing. They are a highly useful group of chemical compounds because of their low toxicity and eco-friendly nature and the wide variety of possible industrial applications in the bio-remediation, health care, food processing and oil industries. In this chapter we have discussed about research investigations on biosurfactants from nitrogen fixing microorganisms and their applications in agriculture.