Xi Zhang1, Chi Xu1, YingLi Liu1,2, Jing Wang1,2, YunYing Zhao3,4, Yu Deng5,6. 1. National Engineering Laboratory for Cereal Fermentation Technology (NELCF), School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, People's Republic of China. 2. China-Canada Joint Lab of Food Nutrition and Health (Beijing), Beijing Technology & Business University, Beijing, 100048, People's Republic of China. 3. National Engineering Laboratory for Cereal Fermentation Technology (NELCF), School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, People's Republic of China. yunyingzhao@jiangnan.edu.cn. 4. Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, People's Republic of China. yunyingzhao@jiangnan.edu.cn. 5. National Engineering Laboratory for Cereal Fermentation Technology (NELCF), School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, People's Republic of China. dengyu@jiangnan.edu.cn. 6. Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, People's Republic of China. dengyu@jiangnan.edu.cn.
Abstract
OBJECTIVE: To enhance the glucaric acid (GA) production in Saccharomyces cerevisiae, the Vitreoscilla hemoglobin was employed to reinforce cellular oxygen supplement. Additionally, the pH-free fermentation strategy was engaged to lower the cost brought by base feeding during the acid-accumulated and long-period glucaric acid production. RESULTS: Recombinant yeast Bga-4 was constructed harboring Vitreoscilla hemoglobin on the basis of previous Bga-3. Higher glucose uptake rate, growth rate, and ethanol reuse rate were achieved in Bga-4 in shake-flask fermentation than those in Bga-3. Furthermore, the fed-batch fermentation in a 5-L bioreactor was performed without pH control, resulting in a final glucaric acid titer of 6.38 g/L. CONCLUSIONS: Both the GA titer and biomass were enhanced along with the efficiency of ethanol re-utilization in the presence of VHb. Moreover, the absence of base feeding for long-period fermentation reduced production cost, which is meaningful for industrial applications.
OBJECTIVE: To enhance the glucaric acid (GA) production in Saccharomyces cerevisiae, the Vitreoscilla hemoglobin was employed to reinforce cellular oxygen supplement. Additionally, the pH-free fermentation strategy was engaged to lower the cost brought by base feeding during the acid-accumulated and long-period glucaric acid production. RESULTS: Recombinant yeast Bga-4 was constructed harboring Vitreoscilla hemoglobin on the basis of previous Bga-3. Higher glucose uptake rate, growth rate, and ethanol reuse rate were achieved in Bga-4 in shake-flask fermentation than those in Bga-3. Furthermore, the fed-batch fermentation in a 5-L bioreactor was performed without pH control, resulting in a final glucaric acid titer of 6.38 g/L. CONCLUSIONS: Both the GA titer and biomass were enhanced along with the efficiency of ethanol re-utilization in the presence of VHb. Moreover, the absence of base feeding for long-period fermentation reduced production cost, which is meaningful for industrial applications.