Abstract: A review is presented of EtOH production from plant raw materials in relation to the cost elements of multistage conversion processes and alternatives for improving the production costs.

Abstract: Preliminary studies show minimal conversion of wood by sulfur dioxide at pressures of 38 psi at room temperature. Evaluation studies of Rut-C-30 and Rut-L-5 Trichoderma viride strains were compared. Studies on the continuous production system by manipulating temperature, pH, Tween 80 level substrate concentration, and dilution rate were performed. The known major components of cellulases were characterized. Studies on the reduction of the cost of producing sugar from corn stover were performed. Development of medium for continuous ethanol fermentation is discussed. Experiments show that the growth limiting factors for continuous fermentation were in the yeast extract. Biotin, pantothenic acid, and pyridoxine appear to be growth limiting factors. Addition of other vitamins had no effect on cell yield but increased ethanol production. The flash ferm process is discussed. Utilization of hemicellulose sugars is described. (DC)

Abstract: The capture of solar energy in the form of glycerol-rich cell mass of the halophilic algae Dunaliella offers some unique possibilities for the production of food, fuels, and chemicals. Especially interesting is the possibility for an all-microbial route to liquid fuels such as ethanol starting with CO/sub 2/, although the most immediate applications will probably be the production of glycerol itself. 5 figures, 5 tables.

Abstract: A .42 m/sup 3/ digester was operated for one year with various operational problems. Changing the swine ration from predominantly corn to wheat resulted in lower gas production. The antibiotic lincomycin appears to be detrimental to digester bacteria. Using large organic loading rates during a startup period can lead to digester upset with a resulting decrease in gas production and excessive foaming. Gas production is a good indicator of daily digester performance. But, other information such as TS in effluent indicate digester long-term stability.

Abstract: The objective of this research is to demonstrate on a laboratory scale the technical feasibility of the direct microbial conversion of pretreated wood to ethanol. During the first year of this contract, we investigated the feasibility of biologically delignifying wood with C. pruinosum and directly fermenting the pretreated wood to ethanol with a mixed culture. Bench-top fermentations of a thermophilic bacillus growing on glucose and of a mixed culture of thermophilic sporocytophaga (US) and a thermophilic bacillus growing on microcrystalline and amorphous cellulose were evaluated for growth and ethanol production. In the mixed culture fermentation of amorphous and microcrystalline cellulose, the specific rate of substrate depletion was calculated to be 0.087 hr/sup -1/ and 0.0346 hr/sup -1/, respectively. However, defining the growth requirements of C. pruinosum and sporocytophaga (US) proved more difficult than originally anticipated. In order to achieve the program objectives within the contract period, a revised research plan was developed based upon chemical pretreatment and the direct fermentation of pretreated hardwood to ethanol. In place of the biological delignification pretreatment step, we have substituted a chemically supplemented steam pretreatment step to partially delignify wood and to enhance its accessibility to microbial utilization. Clostridium thermocellum, which ferments cellulose directlymore » to ethanol and acetic acid, has replaced the mixed culture fermentation stage for ethanol production. Research on the production of ethanol from xylose by the thermophilic bacillus ZB-B2 is retained as one means of utilizing the hemicellulose fraction of hardwood. Work on the genetic improvement of the ethanol yields of both cultures by suppressing acetic acid production is also retained. The rationale, experimental approach, and economic considerations of this revised research plan are also presented.« less

Abstract: Progress is reported in studies on the pretreatment of cellulosic materials to facilitate enzymatic hydrolysis, sulfuric acid hydrolysis, investigation of the Purdue processing scheme including an economic analysis, and the fermentability of the enzymatic hydrolyzate. Progress is also reported on enzyme fermentation studies, hydrolysis reactor development, and utilization of hemicellulose sugars. (JSR)

Abstract: This discussion of enzyme saccharification covers the destruction of the cellulose crystalline structure by chemical and physical methods. Delignified rice hull was decomposed >90% using Cx-glucanase, to produce 5-10% glucose solution, which can be used for the production of microbiological protein, fructose, ethanol etc.