| Summary: | 碩士 === 國立高雄海洋科技大學 === 水產食品科學研究所 === 106 === The aims of this study were to investigate the optimal culturing conditions for γ-aminobutyric acid (GABA) production. Lactobacillus brevis RK03 with high GABA production was isolated from fish intestines of Priacanthus macracanthus. The results showed that the optimum conditions for the production of GABA were carbon 1% (w/v) glucose, 3.5% (w/v) yeast extract as nitrogen source, 2 ppm calcium carbonate, cofactor 20 μM pyridoxal phosphate (PLP), the precursor 500 mM monosodium glutamate (MSG), medium initial pH 5.0, temperature of 30℃, and incubation time of 96 hours. A combination of addition of yeast extract at 4.08% (w/v), MSG at 530.71 mM and initial pH of 5.14, as statistically determined by Response Surface Methodology, was obtained to predict the highest GABA yield of 35,841.3 ppm. This predicted yield was not significantly different from the experimental yield (35,554 ppm). Although GABA yield from 10 L fermentor culture only 31,494 ppm, The yield increased from 31,494 to 46,652 ppm by shaking culture at 30 rpm. For industrial production, the dynamics of the fermentation process was investigated in a 10 L fermentation tank. The kinetic parameters of L.brevis RK03 were investigated by Logistic and Luedeking-Piret equations. The results showed that the parameters were maximum specific growth rate 0.1628 (h-1), Yield coefficient -0.2194 (g/g), product yield coefficient -8.2222, cell maintenance factor -1.2148, growth correlation coefficient 8.2222 and non-growth correlation coefficient 0.3311 respectively, the model was studied and compared with the experimental quality. The results show that the predicted values of the model have similar results with the experimental values.
|
|---|
