Dynamic modeling and analyses of simultaneous saccharification and fermentation process to produce bio-ethanol from rice straw

Abstract

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.

Producing bioethanol from cellulosic hydrolyzate via co-immobilized cultivation strategy

“…Several studies have shown that, for bioethanol production, the aeration strategy is as important as substrate feeding. Aeration is also believed to improve the overall productivity of the SSF process (22,23). These experimental results confirm that improving the aeration of PU carriers promotes rapid proliferation of fungi and increases saccharification enzyme production.…”

Recent trends in the modeling of cellulose hydrolysis

“…In the work by Ko et al (2010), rice straw was collected to convert cellulose into ethanol through enzymatic hydrolysis followed by fermentation. In their research, the kinetic model parameters of cellulose saccharification were determined from real experimental data for cellulase hydrolysis.…”

Ethanol Production from Lignocelluloses by Native Strain Klebsiella oxytoca THLC0409

“…Therefore, it is important to find new types of biomass for ethanol production. Lignocellulosic materials such as crop residues, grass straw, saw dust, and wood chips are particularly suitable sources due to their high abundance, low cost, and that their uses do not compete with food supply [1][2][3]. The development of ethanol production from these sources is thus considered as the second-generation biofuel technology.…”