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Ethanol Production (ethanol + production)
Kinds of Ethanol Production Selected AbstractsCARBON SOURCES AND THEIR EFFECT ON GROWTH, ACETIC ACID AND ETHANOL PRODUCTION BY BRETTANOMYCES BRUXELLENSIS IN BATCH CULTUREJOURNAL OF FOOD PROCESS ENGINEERING, Issue 1 2007M.G. AGUILAR USCANGA ABSTRACT The influence of available low-cost carbohydrates as carbon sources on Brettanomyces bruxellensis growth, acetic acid and ethanol production was studied in order to ascertain the viability of this yeast to eventually become an industrial acetic acid producer. Six different raw materials were included as carbon sources (glucose, sugarcane molasses, refined cane sugar, pineapple, sugarcane and beet juices). B. bruxellensis develops in a complex culture medium like plant juices and sugarcane molasses better than in a medium with a simple carbohydrate such as glucose. The maximum acid acetic yield (0.24 g/g) and productivity (0.14 g/L/h) were attained in tests carried out with sugarcane molasses containing 60 g/L sucrose. The strain produced low levels of ethanol in a refined sugarcane medium, but was able to produce a substantial quantity of acetic acid (13 g/L). [source] Modeling and Parameter Identification of the Simultaneous Saccharification-Fermentation Process for Ethanol ProductionBIOTECHNOLOGY PROGRESS, Issue 6 2007Silvia Ochoa Despite many environmental advantages of using alcohol as a fuel, there are still serious questions about its economical feasibility when compared with oil-based fuels. The bioethanol industry needs to be more competitive, and therefore, all stages of its production process must be simple, inexpensive, efficient, and "easy" to control. In recent years, there have been significant improvements in process design, such as in the purification technologies for ethanol dehydration (molecular sieves, pressure swing adsorption, pervaporation, etc.) and in genetic modifications of microbial strains. However, a lot of research effort is still required in optimization and control, where the first step is the development of suitable models of the process, which can be used as a simulated plant, as a soft sensor or as part of the control algorithm. Thus, toward developing good, reliable, and simple but highly predictive models that can be used in the future for optimization and process control applications, in this paper an unstructured and a cybernetic model are proposed and compared for the simultaneous saccharification-fermentation process (SSF) for the production of ethanol from starch by a recombinant Saccharomyces cerevisiae strain. The cybernetic model proposed is a new one that considers the degradation of starch not only into glucose but also into dextrins (reducing sugars) and takes into account the intracellular reactions occurring inside the cells, giving a more detailed description of the process. Furthermore, an identification procedure based on the Metropolis Monte Carlo optimization method coupled with a sensitivity analysis is proposed for the identification of the modelapos;s parameters, employing experimental data reported in the literature. [source] Bioreactor Coupled with Electromagnetic Field Generator: Effects of Extremely Low Frequency Electromagnetic Fields on Ethanol Production by SaccharomycescerevisiaeBIOTECHNOLOGY PROGRESS, Issue 5 2007Victor H. Perez The effect of extremely low frequency (ELF) magnetic fields on ethanol production by Saccharomyces cerevisiae using sugar cane molasses was studied during batch fermentation. The cellular suspension from the fermentor was externally recycled through a stainless steel tube inserted in two magnetic field generators, and consequently, the ethanol production was intensified. Two magnetic field generators were coupled to the bioreactor, which were operated conveniently in simple or combined ways. Therefore, the recycle velocity and intensity of the magnetic field varied in a range of 0.6,1.4 m s,1 and 5,20 mT, respectively. However, under the best conditions with the magnetic field treatment (0.9,1.2 m s,1 and 20 mT plus solenoid), the overall volumetric ethanol productivity was approximately 17% higher than in the control experiment. These results made it possible to verify the effectiveness of the dynamic magnetic treatment since the fermentations with magnetic treatment reached their final stage in less time, i.e., approximately 2 h earlier, when compared with the control experiment. [source] Ethanol production from raw starch by a recombinant yeast having saccharification and fermentation activitiesJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 10 2002Yoshitoshi Nakamura Abstract In order to develop a method for converting raw starch into ethanol efficiently, direct fermentation of ozonized raw starch using a recombinant yeast was investigated. Ozonolysis was carried out as a pretreatment to convert raw starch into ethanol rapidly and efficiently, and then the effect of the ozone degradation conditions on the degree of polymerization and the amount of amylose in a raw starch was determined. Since the degree of polymerization was low and the amount of amylose was high, raw starch treated with an ozone concentration of 40,gm,3 and an ozonation time of 30,min was the material chosen for alcohol fermentation. Though the recombinant yeast could not convert the untreated raw starch, it converted the soluble starch and the ozonized raw starch at a comparatively high yield into ethanol. About 56% of the ozonized raw starch decomposed, and the ethanol concentration obtained from the ozonized raw starch was markedly greater than that obtained from untreated raw starch. The dynamic behavior of cell growth, substrate degradation, and ethanol production was examined in a continuous culture under various dilution rates, and the optimal dilution rate, ie 0.15,h,1, was determined for maximizing the ethanol productivity (amount of ethanol produced per unit time). © 2002 Society of Chemical Industry [source] The potential for first-generation ethanol production from sugarcaneBIOFUELS, BIOPRODUCTS AND BIOREFINING, Issue 1 2010José Goldemberg Abstract Ethanol production from sugarcane, mainly in Brazil, on the basis of first-generation technology (22.5 billion liters, in 2007/2008 season, in 3.4 million hectares) replaces 1% of the gasoline used in the world today and is highly competitive in economic terms with ethanol produced from other crops in the USA and Europe. In this paper we discuss the potential for sugarcane ethanol expansion from two angles: (1) productivity gains which would allow greater production in the same area and (2) geographical expansion to larger areas. The potential of first-generation technology for the production of ethanol from sugarcane is far from being exhausted. There are gains in productivity of approximately a factor of two from genetically modified varieties and a geographical expansion by a factor of ten of the present level of production in many sugar-producing countries. The replacement of 10% of the gasoline used in the world by ethanol from sugarcane seems possible before second-generation technology reaches technological maturity and possibly economic competitiveness. Copyright © 2009 Society of Chemical Industry and John Wiley & Sons, Ltd [source] Ethanol production from paper sludge by simultaneous saccharification and co-fermentation using recombinant xylose-fermenting microorganismsBIOTECHNOLOGY & BIOENGINEERING, Issue 2 2010Jiayi Zhang Abstract Simultaneous saccharification and co-fermentation (SSCF) of waste paper sludge to ethanol was investigated using two recombinant xylose-fermenting microbes: Zymomonas mobilis 8b and Saccharomyces cerevisiae RWB222. S. cerevisiae RWB222 produced over 40,g/L ethanol with a yield of 0.39,g ethanol/g carbohydrate on paper sludge at 37°C, while similar titers and yields were achieved by Z. mobilis 8b at 30°C. Both S. cerevisiae RWB222 and Z. mobilis 8b exhibited decreasing cell viability at 37°C when producing over 40,g/L ethanol. A high ethanol concentration can account for S. cerevisiae RWB222 viability loss, but ethanol concentration was not the only factor influencing Z. mobilis 8b viability loss at 37°C. Over 3,g/L residual glucose was observed at the end of paper sludge SSCF by Z. mobilis 8b, and a statistical analysis revealed that a high calcium concentration originating from paper sludge, a high ethanol concentration, and a high temperature were the key interactive factors resulting in glucose accumulation. The highest ethanol yields were achieved by SSCF of paper sludge with S. cerevisiae RWB222 at 37°C and Z. mobilis 8b at 30°C. With good sugar consumption at 37°C, S. cerevisiae RWB222 was able to gain an improvement in the polysaccharide to sugar yield compared to that at 30°C, whereas Z. mobilis 8b at 30°C had a lower polysaccharide to sugar yield, but a higher sugar to ethanol yield than S. cerevisiae. Both organisms under optimal conditions achieved a 19% higher overall conversion of paper sludge to ethanol than the non-xylose utilizing S. cerevisiae D5A at its optimal process temperature of 37°C. Biotechnol. Bioeng. 2010;107: 235,244. © 2010 Wiley Periodicals, Inc. [source] Bioconversions of maize residues to value-added coproducts using yeast-like fungi,FEMS YEAST RESEARCH, Issue 2 2003Timothy D Leathers Abstract Agricultural residues are abundant potential feedstocks for bioconversions to industrial fuels and chemicals. Every bushel of maize (approximately 25 kg) processed for sweeteners, oil, or ethanol generates nearly 7 kg of protein- and fiber-rich residues. Currently these materials are sold for very low returns as animal feed ingredients. Yeast-like fungi are promising biocatalysts for conversions of agricultural residues. Although corn fiber (pericarp) arabinoxylan is resistant to digestion by commercially available enzymes, a crude mixture of enzymes from the yeast-like fungus Aureobasidium partially saccharifies corn fiber without chemical pretreatment. Sugars derived from corn fiber can be converted to ethanol or other valuable products using a variety of naturally occurring or recombinant yeasts. Examples are presented of Pichia guilliermondii strains for the conversion of corn fiber hydrolysates to the alternative sweetener xylitol. Corn-based fuel ethanol production also generates enormous volumes of low-value stillage residues. These nutritionally rich materials are prospective substrates for numerous yeast fermentations. Strains of Aureobasidium and the red yeast Phaffia rhodozyma utilize stillage residues for production of the polysaccharide pullulan and the carotenoid astaxanthin, respectively. [source] Effects of a hexokinase II deletion on the dynamics of glycolysis in continuous cultures of Saccharomyces cerevisiaeFEMS YEAST RESEARCH, Issue 2 2002Jasper A. Diderich Abstract In glucose-limited aerobic chemostat cultures of a wild-type Saccharomyces cerevisiae and a derived hxk2 null strain, metabolic fluxes were identical. However, the concentrations of intracellular metabolites, especially fructose 1,6-bisphosphate, and hexose-phosphorylating activities differed. Interestingly, the hxk2 null strain showed a higher maximal growth rate and higher Crabtree threshold dilution rate, revealing a higher oxidative capacity for this strain. After a pulse of glucose, aerobic glucose-limited cultures of wild-type S. cerevisiae displayed an overshoot in the intracellular concentrations of glucose 6-phosphate, fructose 6-phosphate, and fructose 1,6-bisphosphate before a new steady state was established, in contrast to the hxk2 null strain which reached a new steady state without overshoot of these metabolites. At low dilution rates the overshoot of intracellular metabolites in the wild-type strain coincided with the immediate production of ethanol after the glucose pulse. In contrast, in the hxk2 null strain the production of ethanol started gradually. However, in spite of the initial differences in ethanol production and dynamic behaviour of the intracellular metabolites, the steady-state fluxes after transition from glucose limitation to glucose excess were not significantly different in the wild-type strain and the hxk2 null strain at any dilution rate. [source] Regional water resource implications of bioethanol production in the Southeastern United StatesGLOBAL CHANGE BIOLOGY, Issue 9 2009JASON M. EVANS Abstract The Energy Independence and Security Act (EISA) of 2007 mandates US production of 136 billion L of biofuel by 2022. This target implies an appropriation of regional primary production for dedicated feedstocks at scales that may dramatically affect water supply, exacerbate existing water quality challenges, and force undesirable environmental resource trade offs. Using a comparative life cycle approach, we assess energy balances and water resource implications for four dedicated ethanol feedstocks , corn, sugarcane, sweet sorghum, and southern pine , in two southeastern states, Florida and Georgia, which are a presumed epicenter for future biofuel production. Net energy benefit ratios for ethanol and coproducts range were 1.26 for corn, 1.94 for sweet sorghum, 2.51 for sugarcane, and 2.97 for southern pine. Corn also has high nitrogen (N) and water demand (11.2 kg GJnet,1 and 188 m3 GJnet,1, respectively) compared with other feedstocks, making it a poor choice for regional ethanol production. Southern pine, in contrast, has relatively low N demand (0.4 kg GJnet,1) and negligible irrigation needs. However, it has comparatively low gross productivity, which results in large land area per unit ethanol production (208 m2 GJnet,1), and, by association, substantial indirect and incremental water use (51 m3 GJnet,1). Ultimately, all four feedstocks require substantial land (10.1, 3.1, 2.5, and 6.1 million ha for corn, sugarcane, sweet sorghum, and pine, respectively), annual N fertilization (3230, 574, 396, 109 million kg N) and annual total water (54 400, 20 840, 8840, and 14 970 million m3) resources when scaled up to meet EISA renewable fuel standards production goals. This production would, in turn, offset only 17.5% of regional gasoline consumption on a gross basis, and substantially less when evaluated on a net basis. Utilization of existing waste biomass sources may ameliorate these effects, but does not obviate the need for dedicated primary feedstock production. Careful scrutiny of environmental trade-offs is necessary before embracing aggressive ethanol production mandates. [source] Ensilage of wilted whole crop rice (Oryza sativa L.) using a roll baler for chopped material: Silage quality in long-term storageGRASSLAND SCIENCE, Issue 2 2007Hidenori Kawamoto Abstract We examined the effects of long-term storage on the fermentation quality, chemical composition, and digestibility of wilted whole crop rice silage prepared using a roll baler for chopped material (set chop length, 13 mm) and compared the results with those obtained by using a conventional roll baler. The roll balers were used for ensiling whole crop rice of three types: (i) dough-ripe stage with light wilting (45% dry matter); (ii) dough-ripe stage with heavy wilting (65% dry matter); and (iii) yellow-ripe stage with light wilting (45% dry matter). The apparent dry matter density was higher in the ensiled roll bales composed of chopped whole crop rice (chopped bales) than in those composed of non-chopped whole crop rice (conventional bales) (195,250 kg m,3 vs 156,218 kg m,3, respectively). The formation of volatile fatty acids and ammonia-nitrogen was low in all types of silage. Further, no marked differences in the chemical composition and apparent dry matter digestibility were observed between silage from the two types of bales. However, there were significant differences in their lactic acid and ethanol contents. The lactic acid production in the conventional silage was low (0.08,0.14% fresh matter), whereas that in the chopped silage was high (0.71,0.97% fresh matter). A lower pH value (pH 4.0,4.3) was retained in the chopped silage after 10 months of storage. High ethanol production (1.1,2.5% fresh matter) was observed in the conventional silage, whereas ethanol production decreased to less than 1% in the chopped silage. These results indicate that although the ethanol fermentation is readily enhanced in the ensilage of wilted whole crop rice performed by a conventional baler, the ensilage performed by a baler for chopped material encourages lactic acid fermentation and suppresses ethanol production over a wide moisture range throughout the long-term storage. [source] Functional enhancement of Sake yeast strains to minimize the production of ethyl carbamate in Sake wineJOURNAL OF APPLIED MICROBIOLOGY, Issue 3 2010M.S. Dahabieh Abstract Aims:, In fermented alcoholic beverages and particularly in Japanese Sake wine, the ubiquitous presence of the probable human carcinogen ethyl carbamate (EC) is a topic of significant concern. This study aims to develop novel methods for the reduction of EC in Sake wine. Methods and Results:, To reduce the high levels of EC in Sake wine, urea-degrading and urea-importing yeast strains were created by integrating linear cassettes containing either the respective DUR1,2 or DUR3 genes, under the control of the constitutively active Saccharomyces cerevisiae PGK1 promoter, into the Sake yeast strains K7 and K9. The self-cloned, urea-degrading Sake strains K7DUR1,2 and K9DUR1,2 produced Sake wine with 87 and 68% less EC, respectively, while the urea-importing Sake yeast strain K7DUR3 reduced EC by 15%. All functionally enhanced yeast strains were shown to be substantially equivalent to their parental strains in terms of fermentation rate, ethanol production, phenotype and transcriptome. Conclusions:, Under the conditions tested, urea-degrading yeast (constitutive DUR1,2 expression) are superior to urea-importing yeast (constitutive DUR3 expression) for EC reduction in Sake wine, and constitutive co-expression of DUR1,2 and DUR3 does not yield synergistic EC reduction. Significance and Impact of the Study:, The self-cloned, substantially equivalent, urea-degrading Sake yeast strains K7DUR1,2 and K9DUR1,2, which contain the integrated DUR1,2 cassette, are capable of highly efficacious EC reduction during Sake brewing trials, are suitable for commercialization and are important tools for modern Sake makers in their efforts to reduce high EC levels in Sake wine. [source] Genome-scale modeling of Synechocystis sp.JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 4 2009PCC 680, prediction of pathway insertion Abstract BACKGROUND: Cyanobacterium Synechocystis sp. PCC 6803 has been used widely as a model system for the study of photosynthetic organisms and higher plants. The aim of this work was to integrate the genomic information, biochemistry and physiological information available for Synechocystis sp. PCC 6803 to reconstruct a metabolic network for system biology investigations. RESULTS: A genome-scale Synechocystis sp. PCC 6803 metabolic network, including 633 genes, 704 metabolites and 831 metabolic reactions, was reconstructed for the study of optimal Synechocystis growth, network capacity and functions. Heterotrophic, photoautotrophic and mixotrophic growth conditions were simulated. The Synechocystis model was used for in silico predictions for the insertion of ethanol fermentation pathway, which is a novel approach for bioenergy and biofuels production developed in the authors' laboratory. Simulations of Synechocystis cell growth and ethanol production were compared with actual metabolic measurements which showed a satisfactory agreement. CONCLUSION: The Synechocystis metabolic network developed in this study is the first genome-scale mathematical model for photosynthetic organisms. The model may be used not only in global understanding of cellular metabolism and photosynthesis, but also in designing metabolic engineering strategies for desirable bio-products. Copyright © 2008 Society of Chemical Industry [source] Effect of oxygen transfer rates on alcohols production by Candida guilliermondii cultivated on soybean hull hydrolysateJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2009Ângela Cristina Schirmer-Michel Abstract BACKGROUND: In this research the use of soybean hull hydrolysate (SHH) as substrate for xylitol and ethanol production using an osmotolerant strain of Candida guilliermondii was studied. The production of alcohols was investigated in batch cultivations in which the variable parameter was the volumetric oxygen mass transfer coefficient (kLa) obtained from three different conditions of air supply: anaerobic (150 rpm, no aeration); microaerobic (300 rpm, 1 vvm), and aerobic (600 rpm, 2 vvm), corresponding to kLa values of 0; 8; and 46 h,1, respectively. RESULTS: SHH, although presenting a very high osmotic pressure (1413 mOsm kg,1), was completely metabolized under aerobic conditions with high biomass productivities of 0.49 g cells (L h),1, with little formation of ethanol. Xylitol was produced under microaeration, with product yield of 0.22 g g,1 xylose, with the formation of glycerol as a by-product. No xylose was metabolized under anaerobic conditions, but ethanol was produced from hexoses with high product yields of 0.5 g g,1. CONCLUSION: These results suggest that the hydrolysis of soybean hull and its conversion to ethanol and other alcohols could be an important use of this agro-industrial waste, which could be used for biofuel, xylitol or biomass production, depending on the aeration conditions of the cultures. Copyright © 2008 Society of Chemical Industry [source] Cell-free ethanol production: the future of fuel ethanol?JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2007Eric J. Allain Abstract The production of fuel ethanol from renewable resources as an economically viable alternative to gasoline is currently the subject of much research. Most studies seek to improve process efficiency by increasing the rate of ethanol production; ultimately, this approach will be limited by the selected ethanol-producing microorganism. Cell-free ethanol production, using only the enzymes involved in the conversion of glucose to ethanol, may offer a practical and beneficial alternative. Mathematical modeling of such a system has suggested that a cell-free process should be capable of producing ethanol much more efficiently than the microbial based process. This finding along with other potential benefits of a microorganism-free process suggests that a cell-free process might significantly improve the economy of fuel ethanol production and is a worthy target for further research. Copyright © 2007 Society of Chemical Industry [source] Zymomonas mobilis: an alternative ethanol producerJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 4 2006Parmjit S Panesar Abstract Zymomonas mobilis is a unique bacterium in the microbial world, and offers a number of advantages over the existing ethanol-producing microorganisms. Being a prokaryote, it is more amenable to genetic manipulations. Thus, it has attracted great attention in the ethanol production world and efforts have been made to commercialize its application for the purpose. Despite the various efforts made worldwide, none of the processes using this microbe has been commercialized owing to certain bottlenecks. To circumvent the hindrances currently associated with a Zymomonas process, researchers have made various attempts to improve the technology using different techniques. This paper reviews the different substrates and the genetic improvement techniques with special emphasis on mutagenesis and recombinant DNA technology used for ethanol production by Zymomonas strains. Copyright © 2006 Society of Chemical Industry [source] Ethanol production from raw starch by a recombinant yeast having saccharification and fermentation activitiesJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 10 2002Yoshitoshi Nakamura Abstract In order to develop a method for converting raw starch into ethanol efficiently, direct fermentation of ozonized raw starch using a recombinant yeast was investigated. Ozonolysis was carried out as a pretreatment to convert raw starch into ethanol rapidly and efficiently, and then the effect of the ozone degradation conditions on the degree of polymerization and the amount of amylose in a raw starch was determined. Since the degree of polymerization was low and the amount of amylose was high, raw starch treated with an ozone concentration of 40,gm,3 and an ozonation time of 30,min was the material chosen for alcohol fermentation. Though the recombinant yeast could not convert the untreated raw starch, it converted the soluble starch and the ozonized raw starch at a comparatively high yield into ethanol. About 56% of the ozonized raw starch decomposed, and the ethanol concentration obtained from the ozonized raw starch was markedly greater than that obtained from untreated raw starch. The dynamic behavior of cell growth, substrate degradation, and ethanol production was examined in a continuous culture under various dilution rates, and the optimal dilution rate, ie 0.15,h,1, was determined for maximizing the ethanol productivity (amount of ethanol produced per unit time). © 2002 Society of Chemical Industry [source] The fermentation of mixtures of D -glucose and D -xylose by Candida shehatae, Pichia stipitis or Pachysolen tannophilus to produce ethanolJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2002Sebastián Sánchez Abstract The fermentation of mixtures of D -glucose and D -xylose by three non-traditional yeasts: Candida shehatae (ATCC 34887), Pachysolen tannophilus (ATCC 32691) and Pichia stipitis (ATCC 58376) have been studied to determine the optimal strain and initial culture conditions for the efficient production of ethanol. The comparison was made on the basis of maximum specific growth rate (µm), biomass productivity, the specific rates of total substrate consumption (qs) and ethanol production (qE) and the overall yields of ethanol and xylitol. All the experiments were performed in stirred-tank batch reactors at a temperature of 30,°C. The initial pH of the culture medium was 4.5. The highest values of µm (above 0.5,h,1) were obtained with P stipitis in cultures containing high concentrations of D -xylose. All three yeasts consumed the two monosaccharides in sequence, beginning with D -glucose. The values of qs diminished during the course of each experiment with all of the yeasts. The highest values of the specific rates of total substrate consumption and ethanol production were obtained with C shehatae (for t,=,10,h, qs and qE were above 5,g,g,1,h,1 and 2,g,g,1,h,1, respectively), although the highest overall ethanol yields were fairly similar with all three yeasts, at around 0.4,g,g,1. © 2002 Society of Chemical Industry [source] Enhanced ethanol production from enzymatically treated steam-exploded rice straw using extractive fermentationJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2001Yoshitoshi Nakamura Abstract Alcohol fermentation of an enzymatic hydrolyzate of exploded rice straw was studied experimentally. Rice straw was treated under variable conditions, such as steam pressure and steaming time. The exploded rice straw was separated into water-soluble material, methanol-soluble lignin, Klason lignin, and a mixture of cellulose and a low molecular weight substance. The effects of steam explosion on the characteristics of the exploded rice straw were clarified from the point of view of the amounts of extractive components. Steam explosion was found to be effective for the delignification of rice straw and for increasing its susceptibility to enzyme hydrolysis and alcohol fermentation. The polysaccharides (cellulose and hemicellulose) in the rice straw treated at a steam pressure of 3.5,MPa with a steaming time of 2,min were hydrolyzed almost completely into monosaccharides, (ie glucose and xylose) by a mixture of Trichoderma viride cellulase (Meicelase) and Aspergillus aculeatus cellulase (Acucelase). The enzymatic hydrolyzate of exploded rice straw was converted into ethanol efficiently by Pichia stipitis and the ethanol yield from sugar was about 86%(w/w) of the theoretical value. The ethanol concentration in a membrane bioreactor coupled with a pervaporation system reached 50,gdm,3 and was about five times higher than that in the culture broth. The energy efficiency (ratio of combustion energy of ethanol produced to energy for steam explosion) reached a maximum value at a pressure of 3.5,MPa for 2,min. © 2001 Society of Chemical Industry [source] NQR1 controls lifespan by regulating the promotion of respiratory metabolism in yeastAGING CELL, Issue 2 2009María Jiménez-Hidalgo Summary The activity and expression of plasma membrane NADH coenzyme Q reductase is increased by calorie restriction (CR) in rodents. Although this effect is well-established and is necessary for CR's ability to delay aging, the mechanism is unknown. Here we show that the Saccharomyces cerevisiae homolog, NADH-Coenzyme Q reductase 1 (NQR1), resides at the plasma membrane and when overexpressed extends both replicative and chronological lifespan. We show that NQR1 extends replicative lifespan in a SIR2-dependent manner by shifting cells towards respiratory metabolism. Chronological lifespan extension, in contrast, occurs via an SIR2-independent decrease in ethanol production. We conclude that NQR1 is a key mediator of lifespan extension by CR through its effects on yeast metabolism and discuss how these findings could suggest a function for this protein in lifespan extension in mammals. [source] CARBON SOURCES AND THEIR EFFECT ON GROWTH, ACETIC ACID AND ETHANOL PRODUCTION BY BRETTANOMYCES BRUXELLENSIS IN BATCH CULTUREJOURNAL OF FOOD PROCESS ENGINEERING, Issue 1 2007M.G. AGUILAR USCANGA ABSTRACT The influence of available low-cost carbohydrates as carbon sources on Brettanomyces bruxellensis growth, acetic acid and ethanol production was studied in order to ascertain the viability of this yeast to eventually become an industrial acetic acid producer. Six different raw materials were included as carbon sources (glucose, sugarcane molasses, refined cane sugar, pineapple, sugarcane and beet juices). B. bruxellensis develops in a complex culture medium like plant juices and sugarcane molasses better than in a medium with a simple carbohydrate such as glucose. The maximum acid acetic yield (0.24 g/g) and productivity (0.14 g/L/h) were attained in tests carried out with sugarcane molasses containing 60 g/L sucrose. The strain produced low levels of ethanol in a refined sugarcane medium, but was able to produce a substantial quantity of acetic acid (13 g/L). [source] Energy optimization for the design of corn-based ethanol plantsAICHE JOURNAL, Issue 6 2008Ramkumar Karuppiah Abstract In this work, we address the problem of optimizing corn-based bioethanol plants through the use of heat integration and mathematical programming techniques. The goal is to reduce the operating costs of the plant. Capital cost, energy usage, and yields,all contribute to production cost. Yield and energy usage also influence the viability of corn-based ethanol as a sustainable fuel. We first propose a limited superstructure of alternative designs including the various process units and utility streams involved in ethanol production. Our objective is to determine the connections in the network and the flow in each stream in the network such that we minimize the energy requirement of the overall plant. This is accomplished through the formulation of a mixed-integer nonlinear programming problem involving short-cut models for mass and energy balances for all the units in the system, where the model is solved through two nonlinear programming subproblems. We then perform a heat integration study on the resulting flowsheet; the modified flowsheet includes multieffect distillation columns that further reduces energy consumption. The results indicate that it is possible to reduce the current steam consumption required in the transformation of corn into fuel grade ethanol by more than 40% compared to initial basic design. © 2008 American Institute of Chemical Engineers AIChE J, 2008 [source] Expression of the inulinase gene from the marine-derived Pichia guilliermondii in Saccharomyces sp.MICROBIAL BIOTECHNOLOGY, Issue 5 2010ethanol production from inulin Summary It has been confirmed that Saccharomyces sp. W0 can produce high concentration of ethanol. In this study, the INU1 gene cloned from the marine-derived Pichia guilliermondii was transformed into uracil mutant of Saccharomyces sp. W0. The positive transformant Inu-66 obtained could produce 34.2 U ml,1 of extracellular inulinase within 72 h of cultivation. It was found that 15.2 U of inulinase activity per one gram of inulin was suitable for inulin hydrolysis and ethanol production by the transformant Inu-66. During the small-scale fermentation, 13.7 ml of ethanol in 100 ml of medium was produced and 99.1% of the added inulin was utilized by the transformant. During the 2 l fermentation, 14.9% (v/v) of ethanol was produced from inulin and 99.5% of the added inulin was converted into ethanol, CO2 and cell mass. [source] Doubled sugar content in sugarcane plants modified to produce a sucrose isomerPLANT BIOTECHNOLOGY JOURNAL, Issue 1 2007Luguang Wu Summary Sucrose is the feedstock for more than half of the world's fuel ethanol production and a major human food. It is harvested primarily from sugarcane and beet. Despite attempts through conventional and molecular breeding, the stored sugar concentration in elite sugarcane cultivars has not been increased for several decades. Recently, genes have been cloned for bacterial isomerase enzymes that convert sucrose into sugars which are not metabolized by plants, but which are digested by humans, with health benefits over sucrose. We hypothesized that an appropriate sucrose isomerase (SI) expression pattern might simultaneously provide a valuable source of beneficial sugars and overcome the sugar yield ceiling in plants. The introduction of an SI gene tailored for vacuolar compartmentation resulted in sugarcane lines with remarkable increases in total stored sugar levels. The high-value sugar isomaltulose was accumulated in storage tissues without any decrease in stored sucrose concentration, resulting in up to doubled total sugar concentrations in harvested juice. The lines with enhanced sugar accumulation also showed increased photosynthesis, sucrose transport and sink strength. This remarkable step above the former ceiling in stored sugar concentration provides a new perspective into plant source,sink relationships, and has substantial potential for enhanced food and biofuel production. [source] Effect of a perfluorocarbon-Pluronic F 68-based emulsion on a Phanerochaete chrysosporium biofilm immobilised in a membrane gradostat bioreactorASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2010S. K. O. Ntwampe Abstract The present study highlights the application of perfluorooctyl bromide (PFOB), an oxygen carrier, in a fixed-film membrane gradostat reactors (MGRs) in which biofilms of Phanerochaete chrysosporium BKMF-1767 (ATCC 24725) were immobilised. The nutrient medium used in the MGRs was supplemented with PFOB and Pluronic F 68 (PF 68) to alleviate limitations associated with the performance of the immobilised fungus. Lower lignin peroxidase production in PFOB/PF 68 cultures was observed compared to manganese peroxidase production, suggesting an insignificant generation of reactive oxygen species (ROS). Lipid peroxidation, quantified by the formation of malondialdehyde, was lower in the immobilised cultures. After successfully applying PFOB and PF 68 to immobilised P. chrysosporium biofilms in the MGRs, the following results were obtained:1 reduced ethanol production,2 reduced trace element accumulation,3 lower ,-glucan production and4 an improved dissolved oxygen penetration ratio in the immobilised biofilms. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of 2-keto-3-deoxy-6-phosphogluconate aldolase from Zymomonas mobilis ZM4ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 4 2010Ho-Chang Ryu Zymomonas mobilis ZM4 is an organism optimized for ethanol production which uses the Entner,Doudoroff (ED) pathway for the breakdown of glucose. The key enzyme in this process is 2-keto-3-deoxy-6-phosphogluconate (KDPG) aldolase, which produces glyceraldehyde 3-phosphate and pyruvate. In order to provide a molecular background for the KDPG aldolase from this ethanologenic organism (zmKDPG aldolase), the ZMO0997 gene of Z. mobilis ZM4 coding for zmKDPG aldolase was cloned and expressed and the purified protein was crystallized from 25%(w/v) polyethylene glycol 3350 and 0.1,M bis-tris pH 5.5. Diffraction data were collected to 1.8,Å resolution using synchrotron radiation. The crystal belonged to the orthorhombic space group P212121, with unit-cell parameters a = 63.7, b = 83.0, c = 117.2,Å. A trimeric zmKDPG aldolase molecule was present in the asymmetric unit, resulting in a crystal volume per unit protein weight of 2.40,Å3,Da,1 and a solvent content of 48%. [source] A conceptual framework for siting biorefineries in the Canadian PrairiesBIOFUELS, BIOPRODUCTS AND BIOREFINING, Issue 4 2010Jason Luk Abstract Ethanol is increasingly used as a means to reduce gasoline consumption. As a result, it has also attracted analysis of its economic, social, and environmental merit. In order for the ethanol production industry to continue to expand, these issues must be confronted in future development. Although technological development is often relied upon, carefully considered ethanol refinery siting also mitigates some of these concerns. Five alternative siting locations were selected in the western Canadian Prairies. These were evaluated using 12 criteria which represent regional resources, economic conditions, government support, or social indicators. The criteria were weighted to represent the perspectives of two stakeholders. The Preference Ranking Organization Method for Enrichment and Evaluations (PROMETHEE) method was applied to this data, ranking the alternative sites. Several future scenarios were created to analyze the sensitivity of the results to both statistical data and subjective inputs. The rankings proved to be robust, and varied little in the different scenarios. Southern Alberta had an advantage with a high ethanol byproduct demand, education level, and ethanol demand. Southern Manitoba benefitted from the lowest labor and miscellaneous costs, due to higher unemployment. Saskatchewan suffers from low byproduct demand and a decrease in water availability while having a heated economy which increases costs. In addition, Saskatchewan as a whole is currently the leader in ethanol production, resulting in less net demand, reduced access to government incentives, and more local competition. Southern Alberta and Southern Manitoba are the optimal regions for future ethanol biorefinery, where as the Saskatchewan locations are the least attractive. © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd [source] The potential for first-generation ethanol production from sugarcaneBIOFUELS, BIOPRODUCTS AND BIOREFINING, Issue 1 2010José Goldemberg Abstract Ethanol production from sugarcane, mainly in Brazil, on the basis of first-generation technology (22.5 billion liters, in 2007/2008 season, in 3.4 million hectares) replaces 1% of the gasoline used in the world today and is highly competitive in economic terms with ethanol produced from other crops in the USA and Europe. In this paper we discuss the potential for sugarcane ethanol expansion from two angles: (1) productivity gains which would allow greater production in the same area and (2) geographical expansion to larger areas. The potential of first-generation technology for the production of ethanol from sugarcane is far from being exhausted. There are gains in productivity of approximately a factor of two from genetically modified varieties and a geographical expansion by a factor of ten of the present level of production in many sugar-producing countries. The replacement of 10% of the gasoline used in the world by ethanol from sugarcane seems possible before second-generation technology reaches technological maturity and possibly economic competitiveness. Copyright © 2009 Society of Chemical Industry and John Wiley & Sons, Ltd [source] Commercializing lignocellulosic bioethanol: technology bottlenecks and possible remediesBIOFUELS, BIOPRODUCTS AND BIOREFINING, Issue 1 2010Saumita Banerjee Abstract With diminishing oil supplies and growing political instability in oil-producing nations, the world is facing a major energy threat which needs to be solved by virtue of alternative energy sources. Bioethanol has received considerable attention in the transportation sector because of its utility as an octane booster, fuel additive, and even as neat fuel. Brazil and the USA have been producing ethanol on a large scale from sugarcane and corn, respectively. However, due to their primary utility as food and feed, these crops cannot meet the global demand for ethanol production as an alternative transportation fuel. Lignocellulosic biomass is projected as a virtually eternal raw material for fuel ethanol production. The main bottleneck so far has been the technology concerns, which do not support cost-effective and competitive production of lignocellulosic bioethanol. This review sheds light on some of the practical approaches that can be adopted to make the production of lignocellulosic bioethanol economically attractive. These include the use of cheaper substrates, cost-effective pre-treatment techniques, overproducing and recombinant strains for maximized ethanol tolerance and yields, improved recovery processes, efficient bioprocess integration, economic exploitation of side products, and energy and waste minimization. An integrated and dedicated approach can help in realizing large-scale commercial production of lignocellulosic bioethanol, and can contribute toward a cleaner and more energy efficient world. Copyright © 2009 Society of Chemical Industry and John Wiley & Sons, Ltd [source] Protein feeds coproduction in biomass conversion to fuels and chemicalsBIOFUELS, BIOPRODUCTS AND BIOREFINING, Issue 2 2009Bruce E. Dale Abstract Agriculture has changed greatly in the past in response to changing human needs. Now agriculture is being called on to provide raw materials for very large-scale fuel and chemical production. Agriculture will change again in response to this demand and all producers and users of agricultural feedstocks will be affected by this change. For example, livestock feeding practices have already changed in response to the availability of distillers' grains from corn ethanol production. A fuels industry based on herbaceous biomass energy crops will be many-fold larger than the existing corn ethanol industry and will produce its own set of impacts on livestock feeding. We explore here one of these impacts: the availability of large new sources of feed protein from biomass energy crops. In addition to structural carbohydrates, such as cellulose and hemicellulose, herbaceous biomass energy crops can easily be produced with approximately 10% protein, called ,leaf protein'. This leaf protein, as exemplified by alfalfa leaf protein, is superior to soybean meal (SBM) protein in its biological value. Leaf protein recovery and processing fit well into many process flow diagrams for biomass fuels. When leaf protein is properly processed to concentrate it and remove antinutritional factors, as we have learned over the years to do with soybean meal protein, protein in leaf protein concentrate (LPC) will probably be at least as valuable in livestock diets as SBM protein. If LPC is used to meet 20% of total animal protein requirements (i.e., market penetration of 20%) then the potential utilization of leaf protein concentrate could reach as much as 24 million metric tons annually. This leaf protein will replace protein from SBM and other sources. This much leaf protein will reduce by approximately 16 million hectares the amount of land required to provide protein for livestock. Likewise the amount of land required to meet fuel needs will effectively be reduced by 8 million hectares because this land will effectively do ,double duty' by producing needed animal protein as well as feedstocks for fuel production. © 2009 Society of Chemical Industry and John Wiley & Sons, Ltd [source] Alkali-based AFEX pretreatment for the conversion of sugarcane bagasse and cane leaf residues to ethanolBIOTECHNOLOGY & BIOENGINEERING, Issue 3 2010Chandraraj Krishnan Abstract Sugarcane is one of the major agricultural crops cultivated in tropical climate regions of the world. Each tonne of raw cane production is associated with the generation of 130,kg dry weight of bagasse after juice extraction and 250,kg dry weight of cane leaf residue postharvest. The annual world production of sugarcane is ,1.6 billion tones, generating 279 MMT tones of biomass residues (bagasse and cane leaf matter) that would be available for cellulosic ethanol production. Here, we investigated the production of cellulosic ethanol from sugar cane bagasse and sugar cane leaf residue using an alkaline pretreatment: ammonia fiber expansion (AFEX). The AFEX pretreatment improved the accessibility of cellulose and hemicelluloses to enzymes during hydrolysis by breaking down the ester linkages and other lignin carbohydrate complex (LCC) bonds and the sugar produced by this process is found to be highly fermentable. The maximum glucan conversion of AFEX pretreated bagasse and cane leaf residue by cellulases was ,85%. Supplementation with hemicellulases during enzymatic hydrolysis improved the xylan conversion up to 95,98%. Xylanase supplementation also contributed to a marginal improvement in the glucan conversion. AFEX-treated cane leaf residue was found to have a greater enzymatic digestibility compared to AFEX-treated bagasse. Co-fermentation of glucose and xylose, produced from high solid loading (6% glucan) hydrolysis of AFEX-treated bagasse and cane leaf residue, using the recombinant Saccharomyces cerevisiae (424A LNH-ST) produced 34,36,g/L of ethanol with 92% theoretical yield. These results demonstrate that AFEX pretreatment is a viable process for conversion of bagasse and cane leaf residue into cellulosic ethanol. Biotechnol. Bioeng. 2010;107: 441,450. © 2010 Wiley Periodicals, Inc. [source] | |||||||||||||||||||||||||||||||