与液态发酵相比,甜高粱秆固态发酵制燃料乙醇具有能耗低、工艺设备简单和排放废物少等优点,近年来引起人们越来越多的注意.发酵动力学是工业放大过程中设计、操作和模拟优化的基础,文中基于实验室自行筛选的高效酵母菌株TSH-SC-1,对甜高粱秆分批固态发酵制乙醇的动力学进行了研究.根据固态发酵实验结果,分别采用Logistic方程、Leudeking-Piret方程和类似Luedeking-Piret方程,建立了描述固态发酵过程中菌体生长、底物消耗和产物生成的动力学模型方程,并利用最小二乘法对模型参数进行非线性拟合.结果表明,酒精作为酵母厌氧呼吸的能量代谢副产物,与菌体生长速率和菌体浓度都有关系,最大比生长速率为0.331/h,维持常数为0.0127 g(糖分)/[g(菌体干重)·h].模型预测值和实验值有良好的拟合性,菌体生长、糖分消耗、乙醇生成3条曲线的相关指数R2分别为0.83,0.996和0.994.表明该动力学模型可以较好地定量描述基于TSH-SC-1菌株的甜高梁秆乙醇固态发酵过程,对指导其下一步过程放大和生产具有实际意义.%Compared with liquid state fermentation, solid state fermentation of sweet sorghum stalks has such advantages as lower energy consumption, simpler process and equipment, and fewer waste water emissions, so it has drawn more and more attention recently. Fermentation kinetics models are the basis of design, operation, simulation and optimization during industrial scale up process. Based on selective yeast TSH-SC-1, we performed research on fermentation kinetics of solid state fermentation of sweet sorghum stalks to produce ethanol. The models for biomass, substrate consumption and product were established respectively based on Logitstic equation, Leudeking-Piret equation and Leudeking-Piret-like equation, and those parameters in the models were estimated by Non-linear Least Squares method. The results showed that, as a by-product of the anaerobic energy metabolism of yeast, ethanol production is related to both the growth rate and content of yeast cells. The maximum specific growth rate and maintenance constant were estimated about 0. 331 h~(-1)and 0. 0127 g sugar/g dry cell/h. The predicted value by the kinetic models could agree well with the experimental data, and the relative index R_2 of the curves of cell growth, sugar consumption and ethanol production were 0. 83 ,0. 996和0. 994 respectively. The results also indicated that the kinetic models could be used to quantitatively describe the process of solid state fermentation to tum sweet sorghum stalks into fuel ethanol.
展开▼
