Poster Presentation 5-14
Thermophilic Anaerobic Fermentation of Waste Biomass for Producing Acetic Acid
Sally Chan and Mark T. Holtzapple
Department of Chemical Engineering Texas A&M University 3122 TAMU College Station, TX 77843
Telephone: (979) 862-4558; E-mail: w0c9515@chennov2.tamu.edu
The purpose of this research was to develop an approach for generating acetic acid from the biodegradable fraction of municipal solid wastes (MSW), sewage sludge (SS), corn stover, and pig manure, by using thermophilic (55oC) anaerobic high-solid fermentation. One of the advantages of using thermophilic, as opposed to mesophilic, fermentation is higher selectivity for acetic acid, which has greater value and demand than other carboxylic acids. One other goal of this research was to maximize substrate conversion, which was accomplished using the MixAlco process. The substrates used were combinations of energy and nutrient/mineral sources: MSW and corn stover provided high carbohydrate content, while SS and pig manure provided good sources for minerals, metals, and vitamins. The fermentation inocula were mixed cultures obtained from rumen fluid, swamp, and marine sources. Because MSW and corn stover consist mainly of cellulose, their hydrolysis becomes the rate-limiting step in cellulose decomposition. Lime pretreatment enhances enzymatic hydrolysis and increases microbial digestibility and thus increases carboxylic acids production. The Continuum Particle Distribution Modeling method was used to predict the final acid product concentrations and substrate conversions at different liquid and substrate feed rates. The predictions will be compared to the experimental results.
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