| Summary: | 碩士 === 大同大學 === 生物工程學系(所) === 93 === 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.
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