Optimization of growth conditions of native alginate-producing Azotobacter strains isolated from kerman soil through carbon and nitrogen sources of culture medium

Background and Aim : Optimization of alginate production during microbial biotechnology process through native productive strains of Azotobacter can have an important impact on microbial production of this important product. In this research, the effect of carbon and nitrogen source parameters of the culture medium on the optimization of alginate production by native Azotobacter isolates from the soil has been investigated.Methods : Azotobacter isolates were inoculated in mannite broth culture medium without carbon source (without mannitol) and fructose, mannitol, glucose and sucrose carbon sources were added separately in ۲% medium and finally incubated. Also for evaluation. Nitrogen source was optimized by ۱% separately nitrogen sources including: peptone, yeast extract, malt extract and casein were added to the culture medium and incubated. Finally, the amount of alginate production from each of the optimized culture media was evaluated by testing the carbazol reagent of the Nutson-Jeans method.Results : The highest alginate production was as follows - In the medium containing carbon source from high to low, respectively: sucrose, glucose, fructose and finally mannitol. - In the medium containing nitrogen source from high to low, respectively: Peptone, malt extract, yeast extract and finally casein.Conclusion : Under equal growth conditions, carbon glucose source and peptone nitrogen source showed the highest efficiency in optimizing alginate production by native Aztobacter strains.