SOIL-BASED ISOLATION AND MASS CULTURE OF AZOTOBACTER: A STEP TOWARD SUSTAINABLE AGRICULTURE

This study focuses on the isolation, identification, and mass cultivation of Azotobacter spp., a free-living nitrogen-fixing bacterium widely recognized for its biofertilizer potential. Soil samples were aseptically collected from the Vastral region of Ahmedabad and subjected to serial dilution followed by primary isolation using Nutrient Agar. Distinct bacterial colonies were purified and characterized through Gram staining and selective media growth on Ashby’s and Mannitol agar, both of which are nitrogen-free. Biochemical tests, including catalase activity, ammonia production, nitrate reduction, starch hydrolysis, and indole production, were conducted to confirm the identity of Azotobacter species. Positive results across these tests supported the classification of the isolates as Azotobacter. The confirmed strains were then cultivated in nitrogen-free liquid media under controlled conditions for mass production. The study demonstrates a systematic approach to isolating and confirming Azotobacter spp. and highlights its potential application in sustainable agriculture as an eco-friendly alternative to chemical fertilizers.