초록
<P>Surfactants have been demonstrated to be effective in increasing the cellulase enzyme efficacy and overall enzymatic hydrolysis efficiency. However, the impact of the surfactant addition on the economic viability and environmental impacts of the bioethanol process has not been well-investigated. The objective of this study was to determine the economic and the environmental impacts of using five surfactant types-polyethylene glycol (PEG) 3000, PEG4000, PEG6000, PEG8000, and Tween80-at various concentrations (8%, 5%, 2%, 1%, 0.75%, 0.5%, 0.25%, and 0% (w/w)) during enzymatic hydrolysis and fermentation of pretreated Banagrass. We used an integrated techno-economic and life cycle assesment to guide the selection of optimal surfactant concentration in the bioethanol process. A surfactant concentration of >2% negatively affects the profitability of ethanol, even when there is a statistically significant increase in glucose and ethanol titers. Based on the overall performance indicators for final ethanol, economic viability and environmental impacts, the addition of PEG6000 at 2% (w/w) were determined to be the optimal option. Glucose and ethanol concentrations of 119.2 ± 5.4 g/L and 55.0 ± 5.8 g/L, respectively, with an 81.5% cellulose conversion rate, were observed for 2% (w/w) PEG6000. Techno-economic and life cycle analysis indicated that 2% w/w PEG6000 addition resulted in ROI of 3.29% and had reduced the global warming potential by 6 g CO<SUB>2</SUB>/MJ ethanol produced.</P><P>A case study of using integrated techno-economic and life cycle assessments as tools to identify hotspots and optimize bioprocess design is presented.</P><BR>[FIG OMISSION]</BR>