Comparative economic assessment of ABE fermentation based on cellulosic and non-cellulosic feedstocks

Biobutanol can become the replacement of petroleum gasoline in near future. However, economic feasibility of biobutanol production from ABE fermentation is suffering due to the unavailability of cheap feedstocks, production inhibition and inefficient product recovery processes. Here, economic analysis of ABE fermentation has been performed based on cellulosic (bagasse, barley straw, wheat straw, corn stover, and switchgrass) and non-cellulosic (glucose, sugarcane, corn, and sago) feedstocks, which are widely and cheaply available in agriculture based countries. Analysis shows that utilization of glucose required 37% lesser total fixed capital cost than the other cellulosic and non-cellulosic feedstocks for the per year production of 10,000 tonnes of butanol. However, the production cost of butanol from glucose was fourfold higher than sugarcane and cellulosic materials because of its (glucose) high cost. The cost of sago also affected threefold production cost of butanol comparative to other feedstocks. Therefore, these two substrates turned the biobutanol production far from being economically feasible. Interestingly, sugarcane and cellulosic materials showed suitability for economically feasible production of butanol with the production cost range of $0.59–$0.75 per kg butanol. Consequently, quantitative variation in the design and process parameters namely fermentor size, plant capacity, production yield using sugarcane and cellulosic materials as raw materials, trigger significant reduction in unitary cost of butanol up to 53%, 19%, and 31% respectively. Therefore, these parameters will play significant role in making the butanol production economical from cheaper feedstocks (sugarcane and cellulosic materials). Further, high sensitivity of production cost from the product yield postulates significant manipulation in genome of butanol producing bacteria for improving the yield of ABE fermentation.