Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/18/2021
Publication Date: 4/2/2021
Citation: Johnston, D., Nghiem, N.P. 2021. Mixed fermentation of corn and pretreated corn stover for fuel ethanol production. Cereal Chemistry. 98:926-934. https://doi.org/10.1002/cche.10434.
Interpretive Summary: Production of cellulosic ethanol in a dedicated production facility faces a number of difficulties. One of these is the low final ethanol concentrations produced that make the economic recovery of the ethanol difficult. To address this problem, we utilized mixed fermentation of pretreated corn stover (a cellulosic feedstock) with conventional corn ethanol fermentation. This allowed us to produce higher ethanol concentrations while still producing cellulosic ethanol. The results show that it is possible to produce some cellulosic ethanol in an existing corn ethanol facility. This will benefit ethanol producers and researchers by providing information that could lead to the utilization of new feedstocks for fuel ethanol.
Technical Abstract: Fuel ethanol is almost exclusively produced from corn with minor contributions from other cereal grains. Cellulosic ethanol production has significant potential as well as serious limitations. The work described, evaluates the direct incorporation of low moisture ammonia pretreated corn stover with the existing corn-based fuel ethanol process. Ethanol yields in the mixed fermentation process increased significantly relative to the control fermentations. Incorporation of 5% pretreated corn stover increased ethanol yields by 12.7% with 10% corn mash and 11.9% with 20% corn mash over corn only control fermentations. Using 20% corn, residual xylose and arabinose were 0.072 and 0.023 grams/gram biomass respectively, indicating addition ethanol potential with a C5 fermenting yeast. DDGS color and lipid contents were negatively impacted; however, the nutrient value of the corn portion is unlikely to be altered.