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[en] The well-to-wheel (WtW) results of biomass-based chains are found to be significantly sensitive to changes in the elements of the chain model such as the land use change. Our new standardization model is based on the conviction that the synthesis of a statistical aggregate of the possibilities that are defined by the major models in the field including GREET and GEMIS would build reliability into the result by buffering against the changes in the elements of the chain model. In this paper we assess a chosen set of biomass-based chains in terms of energy and GHG emissions using the innovative concept of the standardization transport model (STM). Hydrogen was found to be very attractive with the use of waste wood. On the other hand, sugar ethanol was found to be a promising fuel for the reduction of GHG emissions. Unfavorable land use changes and high fertilizers use should be avoided to maximize confidence in significant reductions from sugar ethanol. - Highlights: ► We generate the standardization transport model (STM). ► We measure the uncertainty of well-to-wheel results with the use of biomass. ► Hydrogen from waste wood is a very attractive second generation transport fuel. ► Bioethanol from sugar is a promising first generation transport fuel.
[en] With more than 95% of India's surface transport dependent on imported fossil fuel, India has made a concerted effort to promote biofuel. The newly announced biofuel policy of India stipulates a blending target of 20% for both bioethanol and biodiesel. In the case of biodiesel, complement to fossil fuel diesel, India's predominant transport fuel, this target is to be achieved by cultivating non-edible oil seed plants in wastelands and fallow land. In spite of best effort, very little progress has been made on the ground. As the result, the deadline for blending target of 20% for biodiesel has been postponed from 2011–2012 to 2006–2017. This paper makes an attempt to understand the factors behind the tardy progress in India's biodiesel scene and suggests policy remedies. - Highlights: ► Even after a decade of efforts in promoting biofuel, India's achievement does not augur well. ► Objective is to understand the factors behind tardy progress. ► Suggests policy remedies.
[en] Hydrogen-producing granules formation was studied in a Continuos Stirred Tank Reactor (CSTR). The aim of this process is to later transfer the mixed liquor to a Up-flow Anaerobic Sludge Blanket (UASB) reactor to reduce its start-up period. Vinasses from a national bioethanol-producing industry (from sugar cane) were used as substrate and their anaerobic fermentation was carried out under mesophilic conditions. The seed sludge was collected from an UASB reactor operated in an industrial wastewater treatment plant and it was heat treated to inactivate methanogenic bacteria. Total viable and non-viable material growth curves were generated and it was determined that the exponential growth phase of the thermally pretreated mixed culture was between 20 and 120 h. Finally, the anaerobic fermentation of the vinasses in batch mode for 70 hours, and then in continuous CSTR mode for 7 days, showed to be an effective method for accelerating the formation of hydrogen-producing granules. Using this method, granules with an average size of 1.24 mm were achieved. The good efficiency of the process is attributed to high mass transfer in the CSTR reactor (author)
[es]Se estudio la formacion de granulos productores de hidrogeno en un Reactor de Tanque Agitado Continuo (CSTR), por sus siglas en ingles), con el fin de transferirlos luego a un reactor Up-flow Anaerobic Sludge Blanket (UASB, por sus siglas en ingles) y asi acortar el tiempo de arranque del mismo. El sustrato utilizado fueron vinazas provenientes de una agroindustria nacional productora de etanol a partir de melazas de cana de azucar y su fermentacion anaerobia se llevo a cabo bajo condiciones mesofilicas. Los lodos para realizar la inoculacion del sistema se tomaron de un reactor UASB de una planta de tratamiento de agua industrial, a los cuales se les realizo un tratamiento termico con el objetivo de inhibir el crecimiento de bacterias metanogenicas. Se generaron curvas de crecimiento de materia viable y no viable total, con las cuales se determino que la fase de crecimiento exponencial de las bacterias en cultivo mixto pretratadas termicamente se encontraba entre las 20 y las 120 h. Finalmente, la fermentacion anaerobica de las vinazas durante 70 horas en modo 'batch' (por lotes) y posteriormente durante 7 dias en modo continuo tipo CSTR, demostro ser un procedimiento efectivo para acelerar la formacion de los granulos productores de hidrogeno, lograndose obtener granulos con un tamano promedio de 1,24 mm. La alta eficiencia del proceso se le atribuye a la elevada transferencia de masa que se obtiene en el reactor CSTR (autor)
[en] In November-December 2009, at the end of the France-Brazil year, La Revue de l'energie published a special issue (n. 592) 'Energy in Brazil'. Within this framework, a dozen Brazilian academics and professionals had chosen to examine a number of issues that were hotly debated in their country, including the role of nuclear power, the experience of bio-ethanol, the 'oil surprise' constituted by the great pre-salt discoveries, the institutional evolution of the energy industries and Brazil's place in world geopolitics. Ten years later, what has become of these major issues?
[fr]En novembre-decembre 2009, alors que s'achevait l'annee France-Bresil, La Revue de l'energie publiait un numero special (no. 592) 'L'energie au Bresil'. Dans ce cadre, une dizaine d'universitaires et de professionnels bresiliens avaient choisi d'examiner quelques questions tres debattues dans leur pays, au premier rang desquelles le role du nucleaire, l'experience du bioethanol, la 'surprise petroliere' que constituaient les grandes decouvertes du pre-sal, l'evolution institutionnelle des industries de l'energie et la place du Bresil dans la geopolitique mondiale. Qu'en est-il, dix ans plus tard, de ces grandes questions?
[en] This study aims at the screening of four cultivars of sorghums as a feedstock for bioethanol production. The straw of these varieties were subjected to pretreatment (dilute sulfuric acid) followed by enzyme hydrolysis to evaluate their potential to produce sugars. Four factor full factorial experimental design (2*2*2*4=32) was used to investigate the effects of experimental factors; sorghum varieties (84-Y-01, 85-G-86, Mr. Buster and RARI S-3), acid concentration (1 and 2%), temperature (121 and 140 degree C) and pretreatment time (30 and 60 min). The tested sorghum varieties follow the order 85-G-86 (47 g/100g) > Mr. Buster (44.6 g/100g) > 84-Y-01 (42 g/100g) > RARI S-3 (36 g/100g) for their sugar yield. The factors followed given order of significance; variety > temperature > acid concentration > pretreatment time. Sorghum variety (85-G-86) was selected as an appropriate feedstock for bioethanol production due to its higher sugar yield and lower concentration of by-products and furans. (author)
[en] Bioconversion of hemicellulose sugars is essential for increasing fuel ethanol yields from lignocellulosic biomass. We report for the first time with rape straw, bioethanol production from hemicellulose sugars. Rape straw was pretreated at mild conditions with sulfuric acid to solubilize the hemicellulose fraction. This pretreatment allows obtaining a prehydrolysate, consisting basically in a solution of monomeric hemicellulosic sugars, with low inhibitor concentrations. The remaining water insoluble solid constitutes a cellulose-enriched, free of extractives material. The influence of temperature (120ºC and 130ºC), acid concentration (2-4% w/v) and pretreatment time (30-180 min) on hemicellulose-derived sugars solubilisation was evaluated. The highest hemicellulosic sugars recovery, 72.3%, was achieved at 130ºC with 2% sulfuric acid and 60 min. At these conditions, a concentrated sugars solution, 52.4 g/L, was obtained after three acid consecutive contacts, with 67% xylose and acetic acid concentration above 4.5 g/L. After a detoxification step by activated charcoal or ion-exchange resin, prehydrolysate was fermented by ethanologenic Escherichia coli. An alcoholic solution of 25 g/L and 86% of theoretical ethanol yield was attained after 144 h when the prehydrolysate was detoxified by ion-exchange resin. The results obtained in the present work show sulfuric acid pretreatment under mild conditions and E. coli as an interesting process to exploit hemicellulosic sugars in rape straw. (Author)
[en] Highlights: • Two processing routes using green solvents were used to fractionate Miscanthus. • Purified cellulose fibres were analysed using physicochemical & statistical tools. • Different processes generated fibres with different physicochemical properties, which impacted in downstream processing. - Abstract: Using a biorefinery approach, biomass polymers such as lignin and carbohydrates can be selectively purified from lignocellulosic feedstocks with the aim of generating not only lignocellulosic bioethanol but also high value bio-based compounds. Furthermore, the efficient use of the entire biomass can increase overall feedstock value and significantly contribute to process cost-effectiveness. Therefore, the aim of this work was to fractionate the main compounds of the energy crop Miscanthus x giganteus (MxG) using ‘green’ solvents in order to obtain cellulose-enriched fibres as well as non-toxic streams rich in hemicellulose and lignin. Two processing routes were compared: a direct 1-step modified organosolv method for simultaneous lignin and hemicellulose removal; and a 3-step sequential process using subcritical water extraction for recovery of first extractives then hemicellulose, followed by modified organosolv lignin extraction. Both methods successfully generated cellulose-enriched fibres; from a complex mixture of compounds present in MxG, it was possible to obtain fibres comprising 78% cellulose without the use of commonly-applied toxic solvents that can potentially limit end uses for processed biomass and/or need additional neutralization steps. Fibres generated by the direct and sequential processes were very similar in composition; however, physicochemical analysis of the fibres using scanning electron microscopy, Fourier-transform infrared spectroscopy and principal component analysis confirmed structural differences resulting from the two processing routes, which were demonstrated to have an impact on downstream processing.
[en] The increasing fossil fuel scarcity has led to an urgent need to develop alternative fuels. Currently microorganisms have been extensively used for the production of first-generation biofuels from lignocellulosic biomass. Yeast is the efficient producer of bioethanol among all existing biofuels option. Tools of synthetic biology have revolutionized the field of microbial cell factories especially in the case of ethanol and fatty acid production. Most of the synthetic biology tools have been developed for the industrial workhorse Saccharomyces cerevisiae. The non-conventional yeast systems have several beneficial traits like ethanol tolerance, thermotolerance, inhibitor tolerance, genetic diversity, etc., and synthetic biology have the power to expand these traits. Currently, synthetic biology is slowly widening to the non-conventional yeasts like Hansenula polymorpha, Kluyveromyces lactis, Pichia pastoris, and Yarrowia lipolytica. Herein, we review the basic synthetic biology tools that can apply to non-conventional yeasts. Furthermore, we discuss the recent advances employed to develop efficient biofuel-producing non-conventional yeast strains by metabolic engineering and synthetic biology with recent examples. Looking forward, future synthetic engineering tools’ development and application should focus on unexplored non-conventional yeast species.
[en] Simple fermentation, reflux distillation and blending protocols were developed to produce a bioethanol azeotrope and a hydrous gasohol fuel: the MMSU hBE gasohol fuel, respectively. The 95% fuel-grade hydrous ethanol, MMSU 95 hBE, was produced from sweet sorghum and sugarcane. It was subsequently used to formulate a hydrous gasohol blend: the MMSU hBE-20. Unlike other hydrous gasohol blends, our formulation does not need dispersants, nor cosolvents. When MMSU 95 hBE was added to the commercially available anhydrous E-10, the resulting MMSU hBE 20 was stable at ambient temperature and did not show phase segregation even at refrigerated conditions. Tests of the hydrous gasohol fuel in stationary 4-stroke engines, motorcycles and motor vehicles, revealed no discernible problems. The performance of a 6.5 HP engine fueled with MMSU hBE-20 was similar to that fueled with commercial E-10. Under engine load of 4, 61 and 8 kg, fuel consumption (L/hr), brake horsepower (BHP), brake fuel rate (L/BHP-hr), heat value (Btu/lb), and brake thermal efficiency were also comparable. Further tests show that MMSU 95 hBE can also be used in blends up to E-85, indicating the possibility that it can be used in Flex Fuel Vehicles (FFV) when they become available in the Philippines. The MMSU hBE 20 is a promising fuel for gas powered engines and vehicles. It is more economical and environmentally sustainable to produce and use than blends using anhydrous ethanol. More important, these technologies are scale-adaptable and easily adoptable at the village level to create an enterprise that is economically viable. Current forecast indicate an average production cost of PHP 30 per liter using feedstocks from sugarcane and sweet sorghum. Commercialization of these technologies will open opportunities for village level ethanol production and would be a significant contribution towars the implementation of several Republic Acts: The RA 9637- the Philippine Biofuels Act, RA 9003 - Philippines' Ecological Solid Waste Management Act, RA 9513- The Philippines Renewable Energy Act, and the RA 8749- The Philippine Air Act. (author)
[en] Microalgal biofuels are currently considered to be the most promising alternative to future renewable energy source. Microalgae have great potential to produce various biofuels, including biodiesel, bioethanol, biomethane, and biohydrogen. Cultivation of biofuel-producing microalgae demands favorable environmental conditions, such as suitable light, temperature, nutrients, salinity, and pH. However, these conditions are not always compatible with the conditions beneficial to biofuel production, because biofuel-related compounds (such as lipids and carbohydrates) tend to accumulate under environmental-stress conditions of light, temperature, nutrient, and salt. This paper presents a brief overview of the effects of environmental conditions on production of microalgal biomass and biofuel, with specific emphasis on how to utilize environmental stresses to improve biofuel productivity. The potential avenues of reaping the benefits of enhanced biofuel production by environmental stresses while maintaining high yields of biomass production have been discussed.