Isolation of Free Living Nitrogen Fixing Bacteria from Crude Oil Contaminated Soil

Three bacterial isolates enriched from crude oil contaminated soil, situated nearby Digboi crude oil refinery of Assam; fixed nitrogen heterotrophically and non symbiotically. The three isolates were identified by their 16S rDNA analyses as Acinetobacter junii, Achromobacter sp. and Alcaligenes faecalis. Nitrogenase activity was determined by Acetylene Reduction Assay. Results obtained from the present study relates the potentiality of using nitrogen fixing bacteria to overcome the problem of nitrogen limitation in crude oil contaminated soil. This study also confirms that crude oil may also be considered as a good source of carbon and energy for nitrogen fixing microorganisms.