Biosurfactant Producing Diazotroph Azotobacter salinestris Isolated from North Gujarat

A total of 21 isolate of nitrogen-fixing bacteria were isolated from rhizospheric soils of different agricultural plant species, including rye, maize and wheat, from North Gujarat, using nitrogen-deprived selective isolation conditions. Ability to fix nitrogen was verified by the acetylene reduction assay. Out of them one individual isolate was found to produce biosurfactant. Biosurfactant production was confirmed by conventional screening methods, including haemolytic, drop collapsing and lipase production activity. These studies revealed that the isolate produced surface active agents which degrade oil and hence, find its importance in oil contaminated soils to maintain soil fertility by performing dual role of nitrogen fixation and oil degradation. Molecular identification results from 16S r-DNA analysis were also corroborated by morphological and biochemical data.