Biochemical conversion of sugarcane bagasse into the alcohol fuel mixture of isopropanol-butanol-ethanol (IBE): Is it economically competitive with cellulosic ethanol?

This work presents a techno-economic analysis of the production of isopropanol, butanol, and ethanol (IBE) from sugarcane bagasse using clostridia and compares IBE with cellulosic ethanol for the minimum selling price (MSP) and sustainability aspects. The MSPs of the fuels are similar (15 USD/GJ) provided that glucose and xylose are effectively utilized in both processes, and the IBE process is equipped with a genetically-modified Clostridium species with enhanced IBE yield and a highly productive continuous bioreactor with integrated product recovery. Notably, these technologies can reduce the size (from 23 × 3785-m3 to 3 × 3027-m3 fermentation tanks) and the wastewater footprint (from 50 to 10 m3/m3 IBE) of the IBE plant. Furthermore, given that the production of either fuel results in a similar increase in the value created by the sugarcane biorefinery and its energy efficiency, the alcohol mixture produced by clostridia is a promising alternative to the less energy-dense ethanol fuel.