Techno-economic Implications of Fed-batch Enzymatic Hydrolysis

As ethanol production continues to increase in the United States, cellulosic ethanol continues to gain traction as a viable option for meeting ethanol demands. In this work, a literature review of techno-economic analyses for cellulosic ethanol was conducted. It was found that pretreatment methods greatly affect the ethanol production costs. There is a lack of techno-economic data comparing a batch enzymatic hydrolysis to a fed-batch enzymatic hydrolysis for a separate hydrolysis and fermentation production process. Consequently, a techno-economic analysis comparing cellulosic ethanol production using batch versus fed-batch enzymatic hydrolysis was conducted. SuperPro Designer software (Intelligen, Scotch Plains, New Jersey), a process simulation tool, was used to simulate ethanol production. The simulation revealed that the biggest difference between batch and fed-batch hydrolysis was facilities costs, which decreased by 41% when using fed-batch enzymatic hydrolysis. A sensitivity analysis revealed that our ethanol production costs were most sensitive to the cost of the corn stover biomass. In general our results support the idea that fed-batch enzymatic hydrolysis does improve the techno-economics of cellulosic ethanol production, even if the improvements came in process steps we did not expect. Advisor: Deepak R. Keshwan