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Background: Reducing the cost of producing cellulosic ethanol is essential for the industrialization of biorefinery. Several processes are currently under investigation, but few of these techniques are entirely satisfactory in terms of competitive cost or environmental impact. In this study, a new ethanol and lactic acid (LA) coproduction is proposed. The technique involved addition of waste alkaline peroxide pretreated hydrolysate (mainly LA and hemicelluloses) to the reaction mixture after ethanol fermentation (mainly LA and xylose) to reduce the ethanol production cost. Results: The following processes were investigated to optimize LA production: no addition of hemicelluloses or hydrolysate, addition of recycled hemicelluloses, and addition of concentrated hydrolysate. The addition of concentrated hydrolysate at 48 hours, which resulted in a maximum LA concentration of 22.3 g/L, was the most environment-friendly and cost-effective process. After the improved fermentation, 361 mg LA and 132 mg ethanol were produced from 1 g of raw poplar wood. That is, the production of one gallon of ethanol produced $9 worth of LA. Conclusions: The amount of LA produced from the pretreated hydrolysate and reaction mixture after ethanol fermentation cannot be underestimated. The recovery of hydrolysate rich in LA and hemicelluloses (or xylose) significantly improved LA yield and further reduced the ethanol production cost. [ABSTRACT FROM AUTHOR]

Ligno(hemi)cellulosics (L(h)Cs) as sugarcane bagasse and loblolly pine sawdust are currently being used to produce biofuels such as bioethanol and biobutanol through fermentation of free sugars that are often obtained enzymatically. However, this bioconversion requires a pretreatment to solubilize the hemicellulose fractions, thus facilitating the action of the cellulolytic enzymes. Instead of the main free monosaccharides used in these current models, the modulation of thermopressurized orthophosphoric acid as a pretreatment, in the ranges of 3-12 atm and pH 1.5-2.5, can produce nondigestible oligosaccharides (NDOS) such as xylo-oligosaccharides (XOS) because heteroxylan is present in both types of hardwood and softwood hemicelluloses. A comparative thin-layer chromatographic analysis of the hydrolytic products showed the best conditions for NDOS production to be 7 atm/water, pH 2.25 and 2.50, and 8.5 atm/water for both sources. Particular hydrolysates from 7 atm (171 °C) at pHs 2.25 and 2.50 both for cane bagasse and pine sawdust, with respective oligosaccharide contents of 57 and 59 %, once mixed in a proportion of 1:1 for each plant source, were used in vitro as carbon sources for Bifidobacterium or Lactobacillus. Once both bacteria attained the stationary phase of growth, an unforeseen feature emerged: the preference of B. animalis for bagasse hydrolysates and, conversely, the preference of L. casei for pine hydrolysates. Considering the fact that nutraceutical oligosaccharides from both hemicelluloses correspond to higher value-added byproducts, the technology using a much diluted thermopressurized orthophosphoric acid pretreatment becomes an attractive choice for L(h)Cs. [ABSTRACT FROM AUTHOR]

Abstract: The visibility of using municipal bio-waste, wood shavings, as a potential feedstock for ethanol production was investigated. Dilute acid hydrolysis of wood shavings with H3PO4 was undertaken in autoclave parr reactor. A combined severity factor (CSF) was used to integrate the effects of hydrolysis times, temperature and acid concentration into a single variable. Xylose concentration reached a maximum value of 17g/100g dry mass corresponding to a yield of 100% at the best identified conditions of 2.5wt.% H3PO4, 175°C and 10min reaction time corresponding to a CSF of 1.9. However, for glucose, an average yield of 30% was obtained at 5wt.% H3PO4, 200°C and 10min. Xylose production increased with increasing temperature and acid concentration, but its transformation to the degradation product furfural was also catalysed by those factors. The maximum furfural formed was 3g/100g dry mass, corresponding to the 24% yield. [Copyright &y& Elsevier]

The combustion in bed fluidized appear with good perspectives inside the technological options for the energetic availability from a fuel, given his flexibility as regards the fuels to employ like his possibilities of clean operation and efficient, beside the possibility of change of scale . In this article expose the results achieved to scale of pilot plant of the operation of a reactor of bed fluidized in the combustion of pellets of sawdust with views to his application in the exploitation of the solid waste in the process of production of bioethanol of lignocelulosicos. [ABSTRACT FROM AUTHOR]

Abstract: The feasibility of ethanol production from the construction and demolition (C&D) wood waste acid hydrolysates was investigated. The chemical compositions of the classified C&D wood waste were analyzed. Concentrated sulfuric acid hydrolysis was used to obtain the saccharide hydrolysates and the inhibitors in the hydrolysates were also analyzed. The C&D wood waste composed of lumber, plywood, particleboard, and medium density fiberboard (MDF) had polysaccharide (cellulose, xylan, and glucomannan) fractions of 60.7–67.9%. The sugar composition (glucose, xylose, and mannose) of the C&D wood wastes varied according to the type of wood. The additives used in the wood processing did not appear to be released into the saccharide solution under acid hydrolysis. Although some fermentation inhibitors were detected in the hydrolysates, they did not affect the ethanol production by Pichia stipitis. The hexose sugar-based ethanol yield and ethanol yield efficiency were 0.42–0.46g ethanol/g substrate and 84.7–90.7%, respectively. Therefore, the C&D wood wastes dumped in landfill sites could be used as a raw material feedstock for the production of bioethanol. [Copyright &y& Elsevier]

As demand for oil increases, production from large oil fields is declining at 4–5% annually, and the world production of oil is expected to peak around 2010. In the meantime, there is one liquid fuel that is renewable and can be used in vehicles without major modification of the engine—it is biofuel (biomass fuel). Ethanol is an alcohol-based fuel produced by fermenting and distilling crops such as corn, barley, wheat, and the like. There are a few issues to be discussed regarding the use of ethanol biofuel: (i) there is a possibility that more energy is used to grow and process the raw material (e.g. corn) into ethanol than is contained in the ethanol itself; (ii) it is unclear whether the adoption of ethanol fuel will increase greenhouse gas; and (iii) a common objection to biofuel production is that it could divert agricultural production away from food crops (i.e. subsidized food burning). After analysis of these issues, biofuel production from wood (forest) residues is considered a sustainable approach to a renewable energy-based society. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: Sulfuric acid lignin (SAL), which is formed as a by-product during the production of bioethanol from woody biomass, was solubilized and functionalized by hydrothermal reaction. SAL could be easily dissolved in an alkaline medium, especially sodium hydroxide solution, by this reaction. The soluble part of the reaction products (S-HSAL) could be dissolved at neutral pH. IR spectrometric analysis of SAL revealed that hydrophilic groups were introduced in it during the reaction. The dispersibility of S-HSAL was increased by sulfonation (SS–HSAL), and it was found to be an effective dispersant for gypsum paste. [Copyright &y& Elsevier]