Papers by Keyword: Fuel Ethanol

Abstract: Simultaneous saccharification and fermertation (SSF) were studied to produce ethanol from corn stover, which include three continuous stages, stover pretreatment, cellulose fermentation, and ethanol production. Firstly, the crude was treated by propionic acid, and the disposal rate of lignin and hemicellulose in corn stover was 60.6%, 98.5%, respectively, with a residual rate of cellulose 90.68%. Then, cellulase production was carried out by Trichoderma reesei Rut C-30. 10% stillage and other nutrition were added to the pretreated corn stover, water moisture and initial pH were adjusted to 70% and 4.8, liquid inoculum was (1.7~2.0)×10⁷spore/g stover. The stover was kept under 30°C for 7d, then mixed with equal pretreated stover. Ratio of water was 2, the inoculum was 3.2×10⁷cell (Saccharomyces cerevisiae)/g substrate, After incubated at 36°C for 72h, the SSF process achieved a yield of ethanol (0.326g/g substrate).

Abstract: To study the saccharification conditions of cellulase on lignocellulose material, this paper used corn straw as the material to do research on the effect of cellulase. The hydrolysis factors, including reaction temperature, reaction time and cellulase concentration, were measured in order to determine the optimal saccharification conditions for fuel ethanol production. The results showed that, when the reaction temperature was 45°C, reaction time was 72 h and cellulase concentration was 60 IU/g, the hydrolysis rate can respectively reach 6.25 %, 14.7 % and 14.4 %. By the analysis of orthogonal test, the main factors effects the saccharification was reaction time. And the optimal combination of saccharification conditions was the reaction time of 54 h, the reaction temperature of 45 °C, and the cellulase concentration of 55 IU/g.

Abstract: The pretreatment of bamboo with dilute alkali and the effects on chemical components and enzymatic hydrolysis were studied, and the fiber structural properties of pretreated residues were studied with Scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The results showed that dilute alkali was highly effective in delignification of the biomass, reducing the lignin content by 50-70%. Bamboo solid recovery was 74.40%, and cellulose, hemicellulose and lignin content were 60.02%, 25.93% and 9.08%, respectively, when pretreated with 1.0% sodium hydroxide, with a solid-liquid ratio of 1:10 at 100 °C for 40 min. Under the conditions, the pretreated residue was hydrolyzed for 72 h with cellulose and xylanase dosage 40 FPU/g cellulose, and the hydrolysis yield of cellulose was 81.38% and that of hemicelluloses was 84.78%, resulting in a total of 66.74 g fermentable sugars from 100 g dry bamboo. The SEM pictures indicated that the biomass structure was deformed and its fibers were exposed, and FTIR results verified the lignin removal by the pretreatment.

Abstract: The biomass replaces the petroleum as energy is involved in energy transformations. There are two grade transformations from the wheat which are the fuel ethanol and the marsh gas ferment. The study on their transformation mechanisms and how to improve their energy efficiency will be benefit for both the academic and practical significance. Studies have shown that at least 67.05% wheat energy changes into fuel ethanol and at least 15.46% the rest of accessory substance alcohol lees energy changes into marsh gas. The total energy transformation amount is not less than 82.51%.The ratio of the wheat fuel ethanol input to output is 1.04, and NEV is 1167 MJ. The result shows the values of energy gain are positive.

Abstract: In his paper, we analyzed the cellulosic ethanol lifecycle, and CO₂ emissions in straw planting stage, transport stage,production stage and the final dispose stage which based on the 2001-2010 tenyears of straw resources in Tianjin. Thecalculation is that 0.92-1.1 million tons CO₂ is discharged in the cellulosicethanol life cycle

Abstract: In this paper, multiplier decomposition is adopted to examine the effects of expanding grain-based fuel ethanol and cassava-based fuel ethanol on agriculture in China. The results show that, reasonable development of grain-based fuel ethanol has a greater role than cassava-based fuel ethanol in accelerating China’s economy, improve rural household’s income, and mitigate gap between rich and poor

Abstract: The fuel ethanol industry has been in rapid development in recent years with the US as a leading force, which consumes large amount of corn. In order to assess the impact of corn-ethanol production on global corn price, a VAR model is used in this paper. By impulse responses analysis and variance decomposition analysis the direct impact of corn-ethanol production on global corn price and its relative importance compared with other external factors are proved. The results show that increasing amount of corn used for US ethanol production leads to rapid increases of global corn price when the corn production is steady. The proportion of corn used for ethanol production among total corn production in the US plays an important role in affecting global corn price among all external factors, and the significance of its impact will enhance in the long run. The fuel ethanol industry should turn to non-grain materials in the future to keep the global corn price steady and guarantee global food security, and it’s necessary for all fuel ethanol producers to take action.

Abstract: The conventional ethanol fermentaion is a typical inhibitory process, leading to low productivity and yield. A new ethanol fermentation process coupled with gas stripping and vacuum flash, named as strip-flash fermentation, is proposed. The process is provided with the advantages of both stripping fermentation and flash fermentation, and improves the ethanol productivity by increasing the in-situ ethanol removal. And a model of flash-strip fermentation process was established. The theoretically analyses indicate that increasing gas flux and liquid phase recycling ratio can help to enhance productivity and yield of strip-flash fermentation process, and comparison to striping fermentation or flash fermentation, flash-strip fermentation has shown a better productivity. The results has also shown the possibilities of further application and optimization of this process.

Abstract: The pretreatment of corn stover with dilute sulfuric acid has been investigated by varying the acid concentration (0.5%-1.25%(w/w)) and the temperature (130-160°C). The pretreatment is aimed at improving enzymatic hydrolysis and increasing the fermentability of the biomass. Given the overall sugar yield, the most favourable pretreatment condition was performed with 0.75% sulfuric acid at 150°C for 30min and then with an enzyme loading of cellulase 15 FPU per gram of cellulose, and it resulted in a total of 49.74g glucose and xylose from 100g dry corn stover. The fiber physical feature, structure and property of pretreated residues were studied with Scanning Electron Microscope (SEM) and Fourier transform infrared spectroscopy. The SEM pictures indicated that the biomass structure was deformed and its fibers were exposed by the pretreatment. FTIR study showed that lignin and hemicellulose were partially removed during the diluted sulfuric acid pretreatment.

Abstract: In order to study the nature and function of Pyruvate decarboxylase (PDC, E.C.4.1.1.1), which is the key enzyme to produce ethanol by fermentation; full-length cDNA library was constructed with SMART technique from Monascus anka CICC 5031. The pdc gene, including a 1713-bp open reading frame, encoding a 570 amino acid protein, was obtained by screening the constructed M. anka cDNA library. The pdc gene was successfully heterologously expressed in E.coli BL21(DE3), accounting for 32.7% of total cellular proteins. Recombinant PDC was expressed in prokaryotic cells and purified by affinity chromatography, and native PDC was extracted and purified from M. anka through Sephadex G-25 and DEAE-anion exchange resin. The enzymatic characterization of both recombinant and native PDC were studied, respectively. The specific activity of recombinant and native PDC was 20.2 and 30.11U/mg respectively. Kinetic analysis indicated that recombinant and native PDC had the same optimum conditions: pH6.0, 30°C, the Km value for pyruvate of recombinant PDC was 2.6 mmol/L and native PDC was 0.56 mmol/L. The high activity and stable PDC from M. anka accounts for the new candidate resources of fuel ethanol production.