Production of ethanol from wheat straw (original) (raw)
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Production of Biocellulosic Ethanol from Wheat Straw
Wheat straw is an abundant lignocellulosic feedstock in many parts of the world, and has been selected for producing ethanol in an economically feasible manner. It contains a mixture of sugars (hexoses and pentoses). Two-stage acid hydrolysis was carried out with concentrates of perchloric acid, using wheat straw. The hydrolysate was concentrated by vacuum evaporation to increase the concentration of fermentable sugars, and was detoxified by over-liming to decrease the concentration of fermentation inhibitors. After two-stage acid hydrolysis, the sugars and the inhibitors were measured. The ethanol yields obtained from by converting hexoses and pentoses in the hydrolysate with the co-culture of Saccharomyces cerevisiae and Pichia stipites were higher than the ethanol yields produced with a monoculture of S. cerevisiae. Various conditions for hysdrolysis and fermentation were investigated. The ethanol concentration was 11.42 g/l in 42 h of incubation, with a yield of 0.475 g/g, productivity of 0.272 g/l ·h, and fermentation efficiency of 92.955 %, using a co-culture of Saccharomyces cerevisiae and Pichia stipites.
Ethanol production from mixtures of wheat straw and wheat meal
Biotechnology for Biofuels, 2010
Background: Bioethanol can be produced from sugar-rich, starch-rich (first generation; 1G) or lignocellulosic (second generation; 2G) raw materials. Integration of 2G ethanol with 1G could facilitate the introduction of the 2G technology. The capital cost per ton of fuel produced would be diminished and better utilization of the biomass can be achieved. It would, furthermore, decrease the energy demand of 2G ethanol production and also provide both 1G and 2G plants with heat and electricity. In the current study, steam-pretreated wheat straw (SPWS) was mixed with presaccharified wheat meal (PWM) and converted to ethanol in simultaneous saccharification and fermentation (SSF).
Pilot scale conversion of wheat straw to ethanol via simultaneous saccharification and fermentation
Bioresource technology, 2014
The production of ethanol from wheat straw (WS) by dilute acid pretreatment, bioabatement of fermentation inhibitors by a fungal strain, and simultaneous saccharification and fermentation (SSF) of the bio-abated WS to ethanol using an ethanologenic recombinant bacterium was studied at a pilot scale without sterilization. WS (124.2g/L) was pretreated with dilute H2SO4 in two parallel tube reactors at 160°C. The inhibitors were bio-abated by growing the fungus aerobically. The maximum ethanol produced by SSF of the bio-abated WS by the recombinant Escherichia coli FBR5 at pH 6.0 and 35°C was 36.0g/L in 83h with a productivity of 0.43gL(-1)h(-1). This value corresponds to an ethanol yield of 0.29g/g of WS which is 86% of the theoretical ethanol yield from WS. This is the first report on the production of ethanol by the recombinant bacterium from a lignocellulosic biomass at a pilot scale.
Romanian Biotechnological Letters, 2013
In this work we applied mechanical and physicochemical pretreatment methods to convert agricultural lignocellulosic residual biomass (wheat straw and corn stalks) to ethanol by enzymatic hydrolysis and fermentation. We determined total sugars and glucose released after hydrolysis and concentration of ethanol in the fermentation media. The highest yield of total sugars in wheat straw was observed after physicochemical pretreatment: 35.6 g total sugar/100 g biomass, followed by mechanical pretreated wheat straw: 20.8 g total sugar/100 g biomass, physicochemical pretreated corn stalks: 13.23 g total sugar/100 g biomass and mechanical pretreated corn stalks: 12.73 g total sugar/100 g biomass. The percentages of glucose from total reducing sugar released after hydrolysis of pretreated biomass are: 17.88% in the physicochemical pretreated corn stalks, 15.09% in the mechanical pretreated wheat straw and 20.5% in the physicochemical pretreated wheat straw. The concentrations of ethanol obta...
Ethanol Production From Steam-Explosion Pretreated Wheat Straw
Bioconversion of cereal straw to bioethanol is becoming an attractive alternative to conventional fuel ethanol production from grains. In this work, the best operational conditions for steam-explosion pretreatment of wheat straw for ethanol production by a simultaneous saccharification and fermentation process were studied, using diluted acid [H 2 SO 4 0.9 % (w/w)] and water as preimpregnation agents. Acid-or water-impregnated biomass was steam-exploded at different temperatures (160-200°C) and residence times (5, 10, and 20 min). Composition of solid and filtrate obtained after pretreatment, enzymatic digestibility and ethanol production of pretreated wheat straw at different experimental conditions was analyzed. The best pretreatment conditions to obtain high conversion yield to ethanol (approx 80% of theoretical) of cellulose-rich residue after steam-explosion were 190°C and 10 min or 200°C and 5 min, in acid-impregnated straw. However, 180°C for 10 min in acid-impregnated biomass provided the highest ethanol yield referred to raw material (140 L/t wheat straw), and sugars recovery yield in the filtrate (300 g/kg wheat straw).
2010
Barley straw used in this study contained 34.3% cellulose, 23.0% hemicellulose and 13.3% lignin (moisture, 6.5%). Several pretreatments (dilute acid, lime and alkaline peroxide) and enzymatic saccharification procedures were evaluated for the conversion of barley straw to monomeric sugars. The maximum release of sugars (glucose, 384 mg; xylose, 187 mg; arabinose, 32 mg; total sugars, 604 mg/g; 94% of maximum theoretical sugar yield) from barley straw (10%, w/v) was obtained by alkaline peroxide (2.5% H 2 O 2 , pH 11.5) pretreatment (358C, 24 hours) and enzymatic saccharification (458C, pH 5.0, 120 hours) after diluting 2 times before adding a cocktail of three commercial enzyme preparations (cellulase, b-glucosidase and hemicellulase) each at the dose level of 0.15 ml/g of straw. Dilute acid and lime pretreatments followed by enzymatic saccharification generated 566 mg (88% yield) and 582 mg (91% yield) total sugars/g of barley straw, respectively. The yield of ethanol from the dilute acid pretreated and enzymatically saccharified barley straw hydrolyzate (23.7 g sugars/L) was 11.4 g/L (0.48 g/g available sugars, 0.26 g/g straw) by the mixed sugar utilizing recombinant Escherichia coli strain FBR5 in 17 hours. The ethanol yields were 11.4 and 11.9 g/L from 24.4 and 26.2 g sugars/L obtained from lime and alkaline peroxide pretreated barley straw, respectively. No inhibition of fermentation occurred by any of the three pretreatments under the conditions used.
Production of Bio-Ethanol from Barley Straw and Reed Canary Grass: A Raw Material Study
The aim of the study was to estimate the optimal harvest time and overall potential of barley straw and reed canary grass (RCG) as feedstocks for bio-ethanol production. The estimate was conducted based on samples from field trials in Finland collected during the seasons 2005/06 and 2006/07. The total dry matter (DM) yield for barley was 8-10 metric tons ha -1 , whereof proportion of straw comprised 30%. For RCG the highest DM yield, more 11 tons ha -1 , was obtained one month after seed maturing. The content of soluble sugars decreased drastically when plant got older being the lowest in mature barley straw and in dead plants in spring for RCG. Cellulose and lignin content of barley straw increased until dough stage of grain and changed only slightly thereafter. Changes in hemicellulose content were equal but lesser. Cellulose and lignin content for RCG was higher the later the plant material was harvested. Only minor changes in hemicellulose content were discovered. Barley straw t...
Maejo International Journal of Energy and Environmental Communication (MIJEEC), 2022
Barley straw is a lignocellulose agricultural waste material that can be utilized as a raw material for ethanol production since it is easy to find, cheap, and has the potential to produce ethanol yield. This research aims to select the optimum pretreatment conditions to increase fermentable sugar production during enzymatic hydrolysis for bioethanol production. Initially, sulfuric acid at a concentration of 0.5, 1.0, 1.5, and 2.0% (v/v) pretreated barley straw biomass was applied by autoclaving at 121℃ for 15 lb/in 2 pressure for 15 min. Furthermore, acid-treated barley straw under the alkaline condition with calcium hydroxide concentrations of 1, 2, 3, and 4% (w/v) was autoclaved at 121℃ for 15 lb/in 2 pressure for 15 min. Subsequently, the pretreatment of barley straw in the acetic and alkaline processes was compared. It was found that calcium hydroxide at a concentration of 2% (w/v) gave more sugar concentrations. Finally, combined acid and alkaline pretreatment with 2% of cellulase enzymatic hydrolysis had the highest total sugar concentration of 205.43 g/L and reducing sugar of 134.42 g/L, producing the highest ethanol yield (16.17 g/L) by 24 hours of fermentation.