ABSTRACT
Background: Bacterial Extracellular Polymeric Substances [EPS] are environmental friendly and versatile polymeric materials that are used in a wide range of industries such as: food, textile, cosmetics, and pharmaceuticals. To make the production process of the EPS cost-effective, improvements in the production yield is required which could be implemented through application of processes such as optimized culture conditions, and development of the strains with higher yield [e.g. through genetic manipulation], or using low-cost substrates
Objectives: In this work, the effects of carbon and nitrogen sources were studied in order to improve the EPS production by the submerged cultivation of Chryseobacterium indologenes MUT.2
Materials and Methods: The mesophilic microorganism Chryseobacterium indologenes MUT.2, was grown and maintained in the Luria Bertani agar. The initial basal medium contained: glucose [20 g.L-1], yeast extracts [5 g.L[-1]], K[2]HPO[4] [6 g.L[-1]], NaH[2]PO[4] [7 g.L[-1]], NH[4]CL [0.7 g.L[-1]], and MgSO[4] [0.5 g.L[-1]]. For evaluating the carbon and nitrogen sources' effect on the fermentation performance, cultures were prepared in 500 mL flasks filled with 300 mL of the medium. The single-factor experiments based on statistics was employed to evaluate and optimize the carbon and nitrogen sources for EPS production in the liquid culture medium of Chryseobacterium indologenes MUT.2
Results: The preferred carbon-sources, sucrose and glucose, commonly gave the highest EPS production of 8.32 and 6.37 g.L[-1], respectively, and the maximum EPS production of 8.87 g.L[-1] was achieved when glutamic acid [5 g.L[-1]] was employed as the nitrogen source
Conclusions: In this work, the culture medium for production of EPS by Chryseobacterium indologenes MUT.2 was optimized. Compared to the basal culture medium in shake-flasks and stirred tank bioreactor, the use of optimized culture medium has resulted in a 53% and 73% increase in the EPS production, respectively