Production of Red Pigment of Haloferax mediterranei by Using Extruded Rice Bran and Starch Under Different Conductivity

• Main Authors: Shu-Hui Hsu, 許淑惠
• Other Authors: C. Will Chen
• Format: Others
• Language: en_US
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/41322110018021641713

碩士 === 大同大學 === 生物工程學系(所) === 92 === Haloferax mediterranei, used in this study is an extremely halophilic bacterium that is not easily contaminated. As a result, costs for sterility and fermentation process can be reduced. In this study two carbon materials – glucose and extruded rice bran/starch which is a cheap agricultural ingredients was compared for the source cost. A pH-stat control strategy is performed in a repeated fed-batch fermentation process under varying conductivity to enhance the cell mass of H. mediterranei and the productivity of red pigment. Acetone was found as an excellent extracting solvent. The extracted pigment shows three peaks of absorbance at 530, 495 and 470 nm that are similar to the absorbance profile of bacterioruberin. This study found that the fermentation using extruded rice bran/starch as a carbon source can dramatically increase cell mass of H. mediterranei to 117 g/L and pigment concentration to 361.4 mg/L, when the conductivity was controlled around 3.0 S/m. However, when the conductivity was maintained at 2.5 S/m, pigment concentration can reaches 555.6 mg/L even the maximum cell concentration was only with 83.5 g/L. Therefore, we conclude that low conductivity is beneficial for the massive production of pigments.