Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, 10607, Taiwan, ROC.
Bioprocess Biosyst Eng. 2010 Feb;33(2):195-205. doi: 10.1007/s00449-009-0313-1. Epub 2009 Mar 24.
The rice straw, an agricultural waste from Asians' main provision, was collected as feedstock to convert cellulose into ethanol through the enzymatic hydrolysis and followed by the fermentation process. When the two process steps are performed sequentially, it is referred to as separate hydrolysis and fermentation (SHF). The steps can also be performed simultaneously, i.e., simultaneous saccharification and fermentation (SSF). In this research, the kinetic model parameters of the cellulose saccharification process step using the rice straw as feedstock is obtained from real experimental data of cellulase hydrolysis. Furthermore, this model can be combined with a fermentation model at high glucose and ethanol concentrations to form a SSF model. The fermentation model is based on cybernetic approach from a paper in the literature with an extension of including both the glucose and ethanol inhibition terms to approach more to the actual plants. Dynamic effects of the operating variables in the enzymatic hydrolysis and the fermentation models will be analyzed. The operation of the SSF process will be compared to the SHF process. It is shown that the SSF process is better in reducing the processing time when the product (ethanol) concentration is high. The means to improve the productivity of the overall SSF process, by properly using aeration during the batch operation will also be discussed.
水稻秸秆是亚洲主要粮食作物的农业废弃物，被收集作为原料，通过酶解将纤维素转化为乙醇，然后进行发酵。当这两个工艺步骤顺序进行时，被称为分步水解和发酵（SHF）。这两个步骤也可以同时进行，即同步糖化和发酵（SSF）。在这项研究中，使用水稻秸秆作为原料的纤维素糖化过程步骤的动力学模型参数是从纤维素酶水解的实际实验数据中获得的。此外，该模型可以与高葡萄糖和乙醇浓度下的发酵模型相结合，形成 SSF 模型。发酵模型基于文献中的控制论方法，并进行了扩展，包括葡萄糖和乙醇抑制项，以更接近实际植物。将分析酶解和发酵模型中操作变量的动态效应。将比较 SSF 工艺与 SHF 工艺的操作。结果表明，当产物（乙醇）浓度较高时，SSF 工艺可以更好地缩短加工时间。还将讨论通过在分批操作期间适当通风来提高整体 SSF 工艺生产力的方法。
