Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)


Biology and Microbiology

First Advisor

Carl A. Westby


Since the Arab oil embargo of 1973, we have become increasingly aware of the finite nature of our petroleum supplies. Current studies estimate that our supplies of petroleum will be depleted in the next 25 to 50 years. As supplies diminish and prices rise, we will need alternate forms of energy to take up the slack. One of the leading alternatives is the use of biomass in the production of liquid fuel that is, conversion of cellulose, starch, glucose, or other carbohydrates to ethanol. In the United States, the fuel ethanol industry is still in its infancy. Approximately a dozen large scale plants provide the bulk of the fuel ethanol currently used for octane enhancement and gasohol production. Numerous other large-scale plants are on the drawing board. These larger plants use ethanol production processes which have been extensively studied and characterized. On the other end of the spectrum are the smaller scale, farm or cooperative plants, which produce 0.7 to 4 million liters of ethanol per year. This size plant has only been in existence for 3 - 4 years and, consequently, there is a distinct lack of research information pertaining to them. While the overall process of ethanol production is similar for large and small scale plants, there exists many significant differences between the two scales. It is in these areas of difference where the process must be modernized and optimized before true technical and economical feasibility can be achieved for small scale plants. My research was based upon the small-scale-production of fuel ethanol from biomass. This size operation can be used by large farms, farm-based cooperatives, or community sized plants. The small plant size significantly reduces transportation costs, as the surrounding area supplies the raw materials and uses the products. thus, a community and the surrounding area could substantially reduce their dependence on foreign energy sources, provide a new and stable market for agricultural products, provide new jobs, and stimulate the local economy by adopting a locally based fuel alcohol production system. However, before this industry can be fully developed, the production of fuel ethanol must be modernized so that the process can be carried out more efficiently. It was the purpose of this study, then, to optimize the small-scale production of ethanol by incorporating new technologies into the basic process of fuel ethanol production from biomass. The primary emphasis of my research was to optimize the cooking, fermentation, and centrifugation processes involved in the production of fuel ethanol. This involved an initial study of existing plant procedures and operations for the purpose of collecting baseline data on plant performance. Utilizing this data, plant components, procedures, and feedstocks were then altered so that the process could be optimized in terms of time, temperature, energy, cost, yield, and other significant parameters.

Library of Congress Subject Headings

Biomass energy
Alcohol as fuel



Number of Pages



South Dakota State University