SYNTHESIS OF EXTRACELLULAR AND INTRACELLULAR POLYMERS IN ISOLATES OF AZOTOBACTER SP

A.A.Haleem Khan, Naseem, B. Vidya Vardhini

Abstract: Soil is principal source of diverse group of microorganisms. The bacterial genera-Azotobacter is known asymbiotic diazotroph for long time and used as biofertilizer with multipurpose activities that improve plant productivity by maintaining sustainable soil health. Azotobacter species (A. beijerinckii, A. chroococcum, A. vinelandii) synthesize extracellular (alginate) and intracellular polymer (Poly-ß-hydroxybutyrate). Alginates are linear copolymers of ß-D-mannuronic acid and a-L-guluronic acid. Poly-ßhydroxybutyrate is lipid inclusion body, common in wide range of bacteria. Both the polymers are commercial components with high applied value in different fields. Azotobacter species are used as bio-inoculants in various cultivable crops to improve yield as they fix atmospheric nitrogen asymbiotically. In the present study we have screened the rhizospheric samples of cultivable crop plants like tomato, chili, rice, sugarcane and maize for Azotobacter species. The bacterial isolates were identified based on morphological and biochemical methods. Whey, wheat bran and molasses were used as cheap substrates for production of polymers. The substrates used in our study are inexpensive and could reduce the production cost of these polymers.

Keywords: Alginates, Poly-ß-hydroxybutyrate (PHB), whey, wheat bran, molasses

DOI: https://doi.org/10.15623/ijret.2015.0412044