Biochemical Engineering and Pilot Plant Research and Development Unit, King Mongkut's University of Technology Thonburi, 49 Soi Tientalay 25, Bangkhuntien-Chaytalay Rd, Thakhum, Bangkhuntien, Bangkok, Thailand.
Appl Biochem Biotechnol. 2013 Mar;169(6):1895-909. doi: 10.1007/s12010-013-0100-y. Epub 2013 Jan 24.
Scheffersomyces stipitis was cultivated in an optimized, controlled fed-batch fermentation for production of ethanol from glucose-xylose mixture. Effect of feed medium composition was investigated on sugar utilization and ethanol production. Studying influence of specific cell growth rate on ethanol fermentation performance showed the carbon flow towards ethanol synthesis decreased with increasing cell growth rate. The optimum specific growth rate to achieve efficient ethanol production performance from a glucose-xylose mixture existed at 0.1 h(-1). With these optimized feed medium and cell growth rate, a kinetic model has been utilized to avoid overflow metabolism as well as to ensure a balanced feeding of nutrient substrate in fed-batch system. Fed-batch culture with feeding profile designed based on the model resulted in high titer, yield, and productivity of ethanol compared with batch cultures. The maximal ethanol concentration was 40.7 g/L. The yield and productivity of ethanol production in the optimized fed-batch culture was 1.3 and 2 times higher than those in batch culture. Thus, higher efficiency ethanol production was achieved in this study through fed-batch process optimization. This strategy may contribute to an improvement of ethanol fermentation from lignocellulosic biomass by S. stipitis on the industrial scale.
酿酒酵母（Scheffersomyces stipitis）在优化的、控制的分批补料发酵中进行培养，用于从葡萄糖-木糖混合物中生产乙醇。研究了补料培养基组成对糖利用和乙醇生产的影响。研究特定细胞生长速率对乙醇发酵性能的影响表明，随着细胞生长速率的增加，碳流向乙醇合成的方向减少。从葡萄糖-木糖混合物中实现高效乙醇生产性能的最佳比生长速率为 0.1 h(-1)。利用这些优化的补料培养基和细胞生长速率，采用动力学模型来避免溢出代谢，并确保在分批补料系统中均衡地供给营养底物。基于该模型设计的补料方案进行分批补料培养，与分批培养相比，可提高乙醇的浓度、产率和生产效率。最大乙醇浓度为 40.7 g/L。在优化的分批补料培养中，乙醇的产率和生产效率分别比分批培养提高了 1.3 倍和 2 倍。因此，通过分批补料过程优化，本研究实现了更高效率的乙醇生产。该策略可能有助于提高酿酒酵母（Scheffersomyces stipitis）从木质纤维素生物质发酵生产乙醇的效率，从而在工业规模上得到应用。
