Patents

The invention discloses a process for the preparation of liquid and dry bio-inoculant comprising aerobic nitrogen fixing bacteria Azotobacter sp. by controlling rate of oxygen transfer in the liquid cultures for use as bio-fertilizers and/or for use in the preparation of a fertilizer composition. The bioinoculant is useful as a bio-fertilizer and/or in the preparation of a fertilizer composition. In particular, the invention relates to a method for controlling the oxygen transfer rate in non-symbiotic, nitrogen fixing aerobic bacterial culture during its initial phase of growth so as to maximize the growth rate thereby resulting in rapid fermentation followed by changing the culture conditions so as to achieve a conversion of more than 99% vegetative cells of Azotobacter sp. ATCC4412 into cysts. The invention further relates to a formulation which contains high density of Azotobacter cysts that helps in improving the shelf life, viability and nitrogen fixing ability of the microorganism.