Batch Butanol Fermentation Using Jerusalem Artichoke With Oxidoreduction Potential Control

The use of biobutanol is an ideal solution for energy shortage and environgment pollution. The problems in production are the cost and the shortage of raw material. Jerusalem artichoke is a kind of non-scaple crops which attracts more and more attention as a new substrate. In the previous butanol fermentations with Jerusalem artichoke, low concentration of target products and sugar utilization with acid crash has existed. In this study, oxidoreduction potential (ORP) control strategy and ORP-pH phased control strategy were used to optimize the butanol fermentation with mixed sugar or Jerusalem artichoke.Butanol production and sugar utilization were greatly improved via ORP control strategy during batch acetone-butanol-ethanol (ABE) fermentation using the mixed sugars and jerusalem artichoke with less acids accumulation. The results showed that butanol production were all more than9.10g·L-1while residual sugars concentration and organic acid were all lower than3.20g·L-1and2.10g·L-1, respectively. When ORP was controlled above-460mV, butanol production and total solvents reached13.19g·L-1and19.71g·L-1, respectively, increased by139.38%and117.07%compared to the uncontrolled process.Four batch fermentations using mixed sugars of glucose and fructose were controlled via ORP-pH phased strategy for higher concentration of butanol products. In the four fermentations, butanol production were all more than9.01g·L-1. The fermentation, which pH controlled at5.5until OD reached0.8, then ORP controlled above-460mV, was the most beneficial to butanol accumulation. Butanol production and total solvents reached10.78g-L’1and16.58g·L-1, respectively, increased by95.64%and82.60%compared to the uncontrolled process. The results showed that ORP-pH phased control strategy increased butanol production and the sugar utilization, at the meanwhile, it solved the problem that the fermentation would last too long time using single-ORP-control strategy and that too much organic acid accumulation using single-pH-control strategy, respectively.On the basis of the optimized schemes with mixed sugars, four batch fermentations using jerusalem artichoke were controlled via ORP. The results showed that it was beneficial for bacterial growth and butanol production which were all above6.54g·L-1. When ORP was controlled above-460mV, butanol production and total solvents reached6.88g·L-1and10.94g·L-1, respectively, increased by49.57%and48.44%compared to the uncontrolled process. The results showed that the ORP-control strategy improved the reducing sugar utilization and butanol production which further demonstrate the feasibility of the ORP-control strategy applied to the butanol fermentation using jerusalem artichoke.Three Batch fermentations using jerusalem artichoke were controlled via ORP-pH phased strategy. In the three fermentations, butanol production were all more than5.15g·L-1. The fermentation, which pH controlled at5.5until OD reached1.3, then ORP controlled above-460mV, was the most beneficial to butanol accumulation. Butanol production and total solvents reached7.01g·L-1and11.73g·L-1, respectively, increased by52.39%and59.16%compared to the uncontrolled process. The results showed that ORP-pH phased control strategy promoted butanol production, the bacteria growth and sugar utilization, at the meanwhile, it shortened the fermentation time. However the butanol production didn’t increase too much which need to be explored further.The results presented in this study demonstrated that the ORP-control strategy and ORP-pH phased control strategy can be successfully applied to the butanol fermentation with mixed sugars or jerusalem artichoke for the butanol improvement, which provide important references and practical significance on the key method in the anaerobic fermentation...