Economic Analysis of Cellulase Production by Clostridium thermocellum in Solid State and Submerged Fermentation

Dependence on foreign oil remains a serious issue for the U.S. economy. Additionally, automobile emissions related to petroleum-based, fossil fuel has been cited as one source of environmental problems, such as global warming and reduced air quality. Using agricultural and forest biomass as a source for the biofuel ethanol industry, provides a partial solution by displacing some fossil fuels. However, the use of high cost enzymes as an input is a significant limitation for ethanol production. Economic analyses of cellulase enzyme production costs using solid state cultivation (SSC) are performed and compared to the traditional submerged fermentation (SmF) method. Results from this study indicate that the unit costs for the cellulase enzyme production are $15.67 per kilogram ($/kg) and $40.36/kg, for the SSC and SmF methods, respectively, while the market price for the cellulase enzyme is $36.00/kg. Profitability analysis and sensitivity analysis also provide positive results. Since these results indicate that the SSC method is economical, ethanol production costs may be reduced, with the potential to make ethanol a viable supplemental fuel source in light of current political, economic and environmental issues