| Summary: | 碩士 === 國立中興大學 === 化學工程學系所 === 105 === Succinate, which is one of the acids with the structure of four-carbon and two carboxylic acids, has the wide range of applications, such as surfactant, detergent, extender, foaming agent, and ion chelator and also, it could be the precursor of many important industrial chemicals. Lactate is also one of the chemicals which have the wide range of application such as food, leather, and textile industries. In recent year, lactate was attractive because of the biodegradable plastic of PLA. To produce these products in the same time, Actinobacillus succinogenes was the strains that could produce succinate and lactate with the wide range of carbon source consumption. Although A. succinogenes could produce metabolites of succinate and lactate with high yield, it was easily be contaminated by other bacteria which might be the strains of Lactobacillus and Leuconostoc. In this research, improving the impurity of the strains that caused the contamination of producing lactate to enhance the stability of the A. succinogenes would be studied. The method of purification the strains would be applied in the continuous fermentation and the stability and the performance in producing succinate and lactate would be investigated. In the statuaries of high concentration of lactate, 0.8M Na+, 0.4mM Cu2+, and carbon source for purifying the impurity strains xylose could be the condition to select the A. succinogenes from the contamination of lactate producer. And the efficiency of the purification was high that it could be purified by culturing the impurity strains with xylose once by raising the succinate yield from 37.6% to 58.5%. In the immobilized continuous fermentation, with oleyl alcohol reflux could not only solve to problem of MgCO3 clogging and prolong the operation time from 344h to over 1410h but also make the A. succinogenes produce succinate and lactate with MgCO3 as pH buffer and CO2 resource in the yield of 55.31 % and 91.69% with the productivity of 1.53 g/L/h and 16.87 g/L/h stable. With the stable of the immobilized continuous fermentation, the metabolites of succinate and lactate would switch rapidly with changing carbon source as xylose and glucose and the mass ratio of succinate to acetate was dependent in the value of 2.25 (g/g) which could make sure that the strains in the immobilized continuous fermentation was A. succinogenes. Xylose could be the condition to make the impurity strains be purified and it also had good performance of purification in the immobilized continuous fermentation. With the oleyl alcohol reflux, the immobilized continuous fermentation could be more stable. By switching the carbon source of glucose and xylose could make the mainly metabolites be lactate and succinate which would make the products be purified easily and make the process more attractive and competitive.
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