嗜鹽菌於批次饋料醱酵下之胞內與胞外多醣之研究

Production of Intracellular and Extracellular Polysaccharides by Haloferax mediterranei in the Fed-Batch Fermentation

謝秋蕙(Chiu-Hui Hsieh)

指導教授 ： 陳志成

大同大學/工程學院/生物工程學系所/碩士(2005年)

摘要

已知Haloferax mediterranei的胞外多醣的化學結構中帶有硫酸基，可以考慮開發成抗凝血藥物(如肝素)之替代物。本研究目的乃是探討改變碳源和導電度於批次饋料醱酵培養中對於H. mediterranei 之胞內外多醣的影響。發現以葡萄糖為碳源時，胞外多醣最大濃度為2.14 g/L，胞內多醣最大濃度為2.96 g/L，而單位菌體之胞內多醣含量最大量有125.9 mg/g cell。如果使用擠壓米糠澱粉為碳源時，胞外多醣最大濃度上升為5.24 g/L，而胞內多醣最大濃度下降為1.33 g/L，胞內多醣含量最大量只有72.4 mg/g cell。所以擠壓米糠澱粉會抑制胞內多醣之形成而促成胞外多醣的生產。於提高醱酵液導電度下，胞外多醣最大濃度可達5.57 g/L，胞內多醣最大濃度為1.50 g/L，胞內多醣含量最大值有74.9 mg/g cell。顯示升高導電度對於多醣形成的影響不顯著。同時發現胞外多醣的含硫量約在4.64 ﹪至 5.98 ﹪的範圍，此代表胞外多醣的三糖重複單元裡可能含有1-2個硫酸基。

關鍵字

胞外多醣

並列摘要

Extracellular polysaccharides (EPS) of Haloferax mediterranei contained sulfated groups. The earlier studies showed that the structure and chemical composition of EPS are similar to those of anticoagulant such as heparin. The present study investigated the effects of different carbon sources and conductivity of fermentation broth on the productivity of EPS and intracellular polysaccharides (IPS) during fed-batch culture.
Using glucose as carbon source, the maximum concentration of EPS was 2.14 g/L and IPS was 2.96 g/L. The maximum amount of IPS content was 125.9mg/g cell. Using extruded rice bran/corn starch (ERB/ST) as carbon source, the maximum concentration of EPS was increased to 5.24 g/L but the IPS was decreased to 1.33 g/L and the IPS content was 72.4 mg/g cell. Therefore, using ERB/ST as carbon source seem to enhance the production of EPS and depress the IPS production. When we increased the conductivity of broth, then the maximum EPS could reach 5.57 g/L and IPS was 1.50 g/L with IPS content of 74.9mg/g cell. Therefore, increasing conductivity did not significantly affect the polysaccharides production. The percentage of sulfate in the EPS was measured as 4.64% to 5.98%. These imply that the sulfated groups in the trisaccharides repeated units of EPS were 1-2 groups.

並列關鍵字

extracellular polysaccharide ； Haloferax mediterranei

參考文獻

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