Khani Mojtaba, Bahrami Ali, Chegeni Asma, Ghafari Mohammad Davoud, Mansouran Zadeh ALi
Department of Bioscience and Biotechnology, Malek Ashtar University, Tehran, Iran.
Young Researchers and Elites Club, North Tehran Branch, Islamic Azad University, Tehran, Iran.
Iran J Biotechnol. 2016 Jun;14(2):13-18. doi: 10.15171/ijb.1266.
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 (. through genetic manipulation), or using low-cost substrates.
In this work, the effects of carbon and nitrogen sources were studied in order to improve the EPS production by the submerged cultivation of MUT.2.
The mesophilic microorganism MUT.2, was grown and maintained in the Luria Bertani agar. The initial basal medium contained: glucose (20 g.L), yeast extracts (5 g.L), KHPO (6 g.L), NaHPO (7 g.L), NHCL (0.7 g.L), and MgSO (0.5 g.L). 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 MUT.2.
The preferred carbon-sources, sucrose and glucose, commonly gave the highest EPS production of 8.32 and 6.37 g.L, respectively, and the maximum EPS production of 8.87 g.L was achieved when glutamic acid (5 g.L) was employed as the nitrogen source.
In this work, the culture medium for production of EPS by 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.
细菌胞外聚合物（EPS）是环境友好且用途广泛的聚合材料，应用于食品、纺织、化妆品和制药等众多行业。为使EPS的生产过程具有成本效益，需要提高产量，这可通过优化培养条件、开发高产菌株（通过基因操作）或使用低成本底物等方法来实现。
在本研究中，研究了碳源和氮源对MUT.2菌株深层培养生产EPS的影响，以提高EPS产量。
嗜温微生物MUT.2在Luria Bertani琼脂培养基中生长和保存。初始基础培养基包含：葡萄糖（20 g/L）、酵母提取物（5 g/L）、KH₂PO₄（6 g/L）、Na₂HPO₄（7 g/L）、NH₄Cl（0.7 g/L）和MgSO₄（0.5 g/L）。为评估碳源和氮源对发酵性能的影响，在装有300 mL培养基的500 mL烧瓶中制备培养物。采用基于统计学的单因素实验来评估和优化MUT.2液体培养基中用于EPS生产的碳源和氮源。
优选的碳源蔗糖和葡萄糖通常分别产生最高的EPS产量，为8.32 g/L和6.37 g/L，当使用谷氨酸（5 g/L）作为氮源时，EPS产量最高可达8.87 g/L。
本研究优化了MUT.2生产EPS的培养基。与摇瓶和搅拌罐生物反应器中的基础培养基相比，使用优化后的培养基分别使EPS产量提高了53%和73%。
