Techno-economic analysis of corn stover fungal fermentation to ethanol

Researchers at the Pacific Northwest National Laboratory (PNNL) perform fungal research and development activities to support the goal of promoting renewable energy production as set by the U.S. Department of Energy (DOE). This techno-economic analysis assesses the process economics of ethanol production from lignocellulosic feedstock by fungi to identify promising opportunities, and the research needed to exploit them. Based on literature derived data, four different ethanologen strains are considered in this study: native and recombinant Saccharomyces cerevisiae, the natural pentose-fermenting yeast, Pichia stipitis and the filamentous fungus Fusarium oxysporum. In addition, filamentous fungi are applied in multi-organism and consolidated process configurations. Organism performance and technology readiness are categorized as near-term (<5 years), mid-term (5-10 years), and long-term (>10 years) process deployment. Processes classified as near-term could reasonably be developed in this shorter time frame, as suggested by recent literature. Mid-term technology process models are based on published lab-scale experimental data. Yields near the theoretical limit are classified as long-term technology goals. Among the four ethanologen strains, recombinant S. cerevisiae provides the most attractive process economics as defined by the lowest Minimum Ethanol Selling Price (MESP). This also falls in a range of the model analysis results suggested by literature based on different feedstock and organisms. Moreover, the analysis of mid-term and long-term processes shows improved profitability, revenue and process economics when co-producing chemicals on-site is applied, resulting in 1.98$/gallon of ethanol from a mid-term process scenario. The results of the analysis suggest that the opportunity for fungal fermentation exists for lignocellulosic ethanol production.