| Municipal solid waste (MSW) is a major by-product of most communities. About 240 million tons of MSW are produced annually in the United States, and approximately half of the MSW is composed of cellulosic materials. Several bioconversion techniques have been evaluated to convert lignocellulose-derived sugars into fuels, chemicals and single-cell protein. Clostridium thermoaceticum was chosen as the organism for the bioconversion of sugar to acetic acid, because it theoretically can convert 100% of glucose to acetic acid.;Clostridium thermoaceticum fermented glucose, fructose and xylose in formulated thioglycollate broth (FTB), yielding 2.8, 2.6 and 2.2 moles of acetic acid, respectively, per mole of sugar used. Xylose was fermented preferentially to glucose, and mannose was not used at all when the sugars are fermented in a mixture. The optimum pH for growth of the bacterium was between 6 and 8.5. The addition of 80 mM PO;Municipal solid waste hydrolyzate required pretreatment to improve the substrate for production of acetic acid. Calcium hydroxide treatment of MSW to pH 10-11, followed by charcoal treatment and supplementation with nutrients derived from FTB was most effective in improving the fermentability of MSW by C. thermoaceticum. The culture acclimated to grow in 40% MSW grew faster and produced more acetic acid in MSW than an unacclimated culture.;Under optimum conditions determined by this study (pH 7, 60... |
