Biofuels

Endophytes are microorganisms that live within host plants for at least part of their life and do not cause apparent symptoms of diseases. In general, beneficial endophytes promote host plant growth, increase plant nutrient uptake, inhibit plant pathogen growth, reduce disease severity, and enhance tolerance to environmental stresses. As sustainable and renewable agricultural production (including current biofuel and bioenergy crops) increases in prominence, endophytic microorganisms will play important roles and offer environmentally-friendly methods to increase productivity while reducing chemical inputs. This review discusses various aspects of beneficial fungal and bacterial endophyte interactions with plants, including the physiological and molecular mechansims by which they benefit plant performance. We also discuss the potential for genetic modification of endophytes with useful genes, which could be used to impart additional traits following inoculation with the genetically engineered endophytes. Finally, we review US-issued patents over the past decade which relate to the use of fungal and bacterial endophytes for plant growth and stress tolerance improvement.

While research and development of algal biofuels are currently receiving much interest and funding, they are still not commercially viable at today's fossil fuel prices. However, a niche opportunity may exist where algae are grown as a by-product of high rate algal ponds (HRAPs) operated for wastewater treatment. In addition to significantly better economics, algal biofuel production from wastewater treatment HRAPs has a much smaller environmental footprint compared to commercial algal production HRAPs which consume freshwater and fertilisers. In this paper the critical parameters that limit algal cultivation, production and harvest are reviewed and practical options that may enhance the net harvestable algal production from wastewater treatment HRAPs including CO 2 addition, species control, control of grazers and parasites and bioflocculation are discussed.

Advances in Biochemical Engineering/Biotechnology reviews actual trends in modern biotechnology. Its aim is to cover all aspects of this interdisciplinary technology where knowledge, methods and expertise are required for chemistry, biochemistry, micro-biology, genetics, chemical engineering and computer science. Special volumes are dedicated to selected topics which focus on new biotechnological products and new processes for their synthesis and purification. They give the state-of-the-art of a topic in a comprehensive way thus being a valuable source for the next 3-5 years.

Perennial biofuel crops such as Miscanthus and switchgrass are thought to increase soil organic matter and therefore may increase soil nitrogen (N) mineralization rates. Our objective was to evaluate a range of N-mineralization indices for soils with established biofuel crops and compare these results with soils in a traditional corn and soybean rotation. We sampled surface soil (0-10 cm deep) from switchgrass (6 years after establishment) and Miscanthus plots (5 years) in a high-organic-matter Mollisol. The longest potential N mineralization index, a 24-day incubation, was significantly greater in Miscanthus soils compared to switchgrass and corn-soybean. In addition, 7-day anaerobic N and potassium chloride-extractable ammonium N were both greater in Miscanthus soils compared to switchgrass and corn-soybean. Our results do support our hypothesis that N-mineralization rates are greater in soils under biofuel production.

Decarbonizing the transportation sector is critical to achieving global climate change mitigation. Although biofuels will play an important role in conventional gasoline and diesel applications, bioderived solutions are particularly important in jet fuels and lubricants, for which no other viable renewable alternatives exist. Producing compounds for jet fuel and lubricant base oil applications often requires upgrading fermentation products, such as alcohols and ketones, to reach the appropriate molecular-weight range. Ketones possess both electrophilic and nucleophilic functionality, which allows them to be used as building blocks similar to alkenes and aromatics in a petroleum refining complex. Here, we develop a method for selectively upgrading biomass-derived alkyl methyl ketones with >95% yields into trimer condensates, which can then be hydrodeoxygenated in near-quantitative yields to give a new class of cycloalkane compounds. The basic chemistry developed here can be tailor...

Biomass is a potential energy resource that can be converted to hydrogen and is available from a wide range of sources. In this study, non-conventional biomass sources: soybean (Glycine max.), cassava (Manihot esculenta) and banana rachis (Musa paradisiaca L.) had been tested for hydrogen production from biomass pyrolysis. The influence of biomass microstructure and reducing sugar content on the hydrogen production was studied through a high-energy ball-milling pre-process of the soybean source. The results

Production of biogas from different organic materials is a most interesting source of renewable energy. The biomethane potential (BMP) of these materials has to be determined to get insight in design parameters for anaerobic digesters. Although several norms and guidelines for BMP tests exist, inter-laboratory tests regularly show high variability of BMPs for the same substrate. A workshop was held in June 2015, in Leysin, Switzerland, with over 40 attendees from 30 laboratories around the world, to agree on common solutions to the conundrum of inconsistent BMP test results. This paper presents the consensus of the intense roundtable discussions and cross-comparison of methodologies used in respective laboratories. Compulsory elements for the validation of BMP results were defined. They include the minimal number of replicates, the request to carry out blank and positive control assays, a criterion for the test duration, details on BMP calculation, and last but not least criteria fo...

En julio de 2014, el grupo de Trabajo Abierto de la Asamblea General de las Naciones Unidas propuso un documento con 17 objetivos para su aprobacion en septiembre de 2015. Este documento fijo las pautas para la promulgacion de los Objetivos de Desarrollo Sostenible y la agenda global de desarrollo en el periodo 2015 – 2030; esfuerzo que marca unas nuevas bases para los planes gubernamentales de crecimiento de las naciones. La propuesta de los Objetivos de Desarrollo Sostenible plantea unos retos para Colombia en diferentes sectores y una vision sistemica y no fraccionada del desarrollo para garantizar la sustentabilidad. En este documento se describen los incentivos fiscales en la produccion de biocombustible y se reflexiona en los dilemas que surgen a la luz de los Objetivos de Desarrollo Sostenible. Bajo este contexto surgen preguntas sobre los limites y alcances de los contadores publicos y su rol dentro del ejercicio profesional de la contabilidad ambiental.

Biodiesel is an alternative fuel and fuel extender easily derived from vegetable oil or animal fat. In 2006, the US Environmental Protection Agency mandated that maximum sulfur content of diesel fuels be reduced to 15 ppm to protect catalysts employed in exhaust aftertreatment devices. Processing to produce this ultra-low sulfur petrodiesel (ULSD) alters fuel lubricity, density, cold flow, viscosity, and other properties. Consequently, there is a need to develop a better understanding of the basic fuel properties of biodiesel/ULSD blends. This work evaluates the effects of biodiesel volumetric blend ratio (V BD) on cloud point (CP), kinematic viscosity (m), specific gravity (SG), and refractive index (RI) of blends with petrodiesel. Properties measured for various blends of methyl esters of soybean oil (SME) and used cooking oil (UCOME) in ULSD were compared with those for blends with low sulfur (B500 ppm) petrodiesel fuel (LSD). With respect to increasing V BD , CP and SG increased and RI decreased with each parameter demonstrating a linear correlation. In contrast, m showed a curvilinear relationship with respect to increasing V BD. Calibration curves were derived from regression analyses to determine V BD in biodiesel/ULSD blends from measurements of each individual property. While the models had generally high coefficients of regression (R 2 [ 0.986), SG models were most accurate for predicting V BD to within 1.3 vol%. Keywords Biodiesel Á Blend ratio Á Cloud point Á Refractive index Á Specific gravity Á Kinematic viscosity Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the US Department of Agriculture. USDA is an equal opportunity provider and employer.

Crop residues are common in rural Ghana due to the predominant role agriculture plays in livelihood activities in these communities. In this paper we investigate the prospects of exploiting agricultural crop residues for rural development in Ghana through bioenergy schemes. A theoretical energy potential of 623.84 PJ per year, which is equivalent to 19,781 MW was estimated using crop production data from the Food and Agricultural Organization of the United Nations and residue-to-product ratios. Ghana has a total installed generation capacity of 4577 MW which is four times less the energy potential of crop residues in the country. Cocoa pod husks were identified as important biomass resources for energy generation as they are currently wasted. To further assess the energy potential of cocoa pod husks, different cocoa pod husks samples were collected across the six cocoa growing regions in Ghana and thermo-chemically characterised using proximate and ultimate analysis. The low levels of nitrogen and sulphur observed, together with the high heating value, suggest that cocoa pod husks and for that matter crop residues are eco-friendly feedstock that can be used to power rural communities in Ghana.

The present study deals with the biohydrogen production from starch-containing wastewater collected from the textile industry in Taiwan. The effects of inoculums collected from different sources (sewage sludge, soil and cow dung), substrate concentrations (5–25 g COD/L) and pH (4.0–8.0) on hydrogen production from wastewater were investigated.The cow dung seed had the highest hydrogen production of 101 mL with hydrogen content in biogas of 32.2%. It corresponds to a hydrogen yield (HY) of 1.56 mol H2/mol hexose and hydrogen production rate (HPR) of 0.93 L/L/d. Response surface methodology was used to evaluate the effects of initial cultivation pH (4.0–8.0) and substrate concentration (5–25 g COD/L) on the hydrogen production at 35 °C. At pH 7.0 with a wastewater concentration of 20 g COD/L, a maximum hydrogen production of 66 mL with 31.9% H2 and corresponding to an HY of 0.97 mol H2/mol hexose and an HPR of 1.14 L/L/d were obtained. According to the response surface analysis, the optimal conditions for high HPR were a wastewater concentration of 13 g COD/L at an initial cultivation pH of 7.0. The main soluble metabolic products were acetate and butyrate for hydrogen fermentation from textile wastewater.► The textile wastewater containing starch is a potential energy resource for anaerobic hydrogen fermentation. ► The optimum initial cultivation pH for H2production was 7.0. ► The optimum wastewater concentration for H2 production was 13 g COD/L. ► The main soluble metabolic products were acetate and butyrate.

Ideal bacterial support medium for fixed film denitrification processes/bioreactors must be inexpensive, durable and possess large surface area with sufficient porosity. The present study has been focussed on removing nitrate nitrogen at two different nitrate nitrogen loading rates (60 (NLR I) and 120 (NLR II) mg l-1) from simulated aquaculture wastewater. Coconut coir fibre and a commercially available synthetic reticulated plastic media (Fujino Spirals) were used as packing medium in two independent upflow anaerobic packed bed column reactors. Removal of nitrate nitrogen was studied in correlation with other nutrients (COD, TKN, dissolved orthophosphate). Maximum removal of 97% at NLR-I and 99% at NLR – II of nitrate nitrogen was observed in with either media. Greater consistency in the case of COD removal of upto 81% was observed at NLR II where coconut coir was used as support medium compared to 72% COD removal by Fujino Spirals. The results observed indicate that the organic support medium is just as efficient in nitrate nitrogen removal as conventionally used synthetic support medium. The study is important as it specifically focuses on denitrification of aquaculture wastewater using cheaper organic support medium in anoxic bioreactors for the removal of nitrate nitrogen; which is seldom addressed as a significant problem.

h i g h l i g h t s " A purification step of the methyl acetate is needed to remove contaminants. " Adsorption isotherms of methyl acetate mixtures correlated with a Langmuir model. " Breakthrough curves showed the feasibility of the adsorption on zeolite 5A.

Biofuels have been considerably developed as a probable alternative resource of fossil fuel. In recent times, the continuously increasingdemand and prices of fossil fuel as well asclimate change, makes biodiesel and bioethanol as the only key target for future energy market especially in transportation sector.A large amount of biodiesel and bioethanol productions cost belongs to feedstock that makes it to be as an essential issue for the future of biofuel. The significance of feedstock will be increased while it derives from food feedstock.The purpose of this paper is to describe various type of biodiesel and bioethanol feedstock. Apart from that, this paper will also attempt to compare the biodiesel and bioethanol respect to feedstock.

According to the United Nation Development Programme, access to modern low-cost energy systems in developing countries is important in the realization of the globally agreed developmental goals, as well as the Millennium Development Goals, and sustainable development, which would assist in the reduction of poverty and to improve the conditions and quality of life for the greater part of the world's population. Planners have suggested hybrid energy system for the electrification of rural areas worldwide. This study investigates the techno-economic and environmental effect of applying demand side management (DSM) activities to rural loads before design and sizing of hybrid energy systems for such community. Iporin a rural area in Ibadan, Nigeria which is endowed with an average daily solar radiation of 3.84 kWh/m 2 /day was taken as a case study. The total daily consumption which was initially estimated as 297 kWh/day after the application of DSM techniques dropped to 130 kWh/day representing a decrease of 56.80 %. Hybrid Optimization Model for Electric Renewables software was used for simulation and optimization purpose. Parameters such as DSM index, net present cost, and emission level were used in determining the effect of the DSM technique. Overall, the DSM activities proved to be more economical and environmental friendly.

Gasification of biomass produces a mixture of gas (mainly carbon monoxide (CO), carbon dioxide (CO 2), and hydrogen (H 2)) called synthesis gas, or syngas, by thermal degradation without combustion. Syngas can be used for heat or electricity production by thermochemical processes. This project aims at developing an alternative way to bioupgrade syngas into biogas (mainly methane), via anaerobic fermentation. Nonacclimated industrial granular sludge to be used as reactor inoculum was initially evaluated for mesophilic carboxydotrophic methanogenesis potential in batch tests at 4 and 8 mmol CO/g VSS.d, in the absence and presence of H 2 and CO 2 , respectively. Granular sludge was then introduced into a 30 L gas-lift reactor and supplied with CO, to study the production of methane and other metabolites, at different gas dilutions as well as feeding and recirculation rates. A maximal CO conversion efficiency of 75%, which was gas-liquid mass transfer limited, occurred at a CO partial pressure of 0.6 atm combined with a gas recirculation ratio of 20:1. The anaerobic granule potential for methanogenesis from CO was likely hydrogenotrophic, combined with CO-dependent H 2 formation, either under mesophilic or thermophilic conditions. Thermophilic conditions provide the anaerobic granules with a CO-bioconversion potential significantly larger (5-fold) than under mesophilic conditions, so long as the gas-liquid transfer is alleviated.

Switchgrass (Panicum virgatum L.) is a potential biofuel crop in the midwestern United States. The objective of this experiment was to test the effect of nitrogen application on biomass dry matter yield and fiber and mineral concentrations in large field plots in Lucas and Wayne counties in southern Iowa. Two established switchgrass fields with a previous history of limited management were evaluated from 1998 through 2002. Nitrogen was applied in the spring at rates of 0, 56, 112, and 224 kg N ha −1 , and a single biomass harvest was made in autumn. Biomass production averaged across locations and N levels increased by 3.6 mg ha −1 between 1998 and 2002 to 6.5 mg ha −1. Nitrogen improved yields, with the response declining as N levels increased. The highest yield throughout the experiment was 8.5 mg ha −1 at the Lucas location in 2002. Changes in fiber and mineral concentrations did not follow any trend over years but were likely due to differences in harvest date among years. Nitrogen fertilization had no meaningful effect on the quality of the biofuel produced. This study clearly shows that nitrogen application and proper agronomic management can substantially increase the yield of established switchgrass fields over time without affecting the quality of the feedstock. As this experiment was conducted in large plots using commercial farm machinery, the results should be broadly applicable to real world situations.

Several wastes from agro-industrial activities were mixed in different ratios to evaluate the co-digestion process. Methane yield ðY CH 4 Þ, specific methanogenic activity (SMA) and a kinetic parameter (k 0) were determined. A second feeding was also performed to examine the recovery of bacterial activity after exhaustion. Mixture ratios of 1:1:1:1 and 1:3:4:0.5 (w/w) showed the best performance, with Y CH 4 of 664; 582 NmL CH 4 /gVS substrate , as well as SMA of 0.12; 0.13 gCOD NmLCH 4 =gVS inoculum =d, respectively, during the digestion of the first feed. It was possible to relate synergetic effects with enhancement in Y CH 4 by up to 43%, compared with values calculated from Y CH 4 of the individual substrates. All batches started up the biogas production after an exhaustion period, when a second feed was added. However, long lag phases (up to 21 days) were observed due to stressed conditions caused by the substrate limitation prior to the second feed.

This paper assesses the global and sectoral implications of the European Union Biofuels Directive (BFD) in a multi-region computable general equilibrium framework with endogenous determination of land supply. The results show that, without mandatory blending policies or subsidies to stimulate the use of biofuel crops in the petroleum sector, the targets of the BFD will not be met in 2010 and 2020. With a mandatory blending policy, the enhanced demand for biofuel crops has a strong impact on agriculture at the global and European levels. The additional demand from the energy sector leads to an increase in global land use and, ultimately, a decrease in biodiversity. The development, on the other hand, might slow or reverse the long-term process of declining real agricultural prices. Moreover, assuming a further liberalization of the European agricultural market imports of biofuels are expected to increase to more than 50% of the total biofuel demand in Europe.

we are highlighting how the biofuel as an alternative fuel source, presents the advantages behind using such an energy source, challenges behind using it, and what is the expectation of this source on the future. We will go through Brazil as a country which is making benefits behind using this clean source; and the urges of its future on using this source.

Batang Ai reservoir has been an inland aquaculture site. However, little is known about the water quality of the reservoir which is important for aquaculture expansion. Therefore, the objective of this study was to determine the level of dissolved oxygen (DO), biochemical oxygen demand (BOD 5 ) and sulfide in the reservoir. Samplings were conducted at 12 stations and at three different depths. Results show that pH and dissolved oxygen decreased as depth increased. Mean DO at 0.5 m, 14 m and 27 m were 6.4 mg/L, 3.9 mg/L and 2.95 mg/L respectively. BOD 5 were 3.9 mg/L, 8.7 mg/L and 8.3 mg/L at 0.5 m, 14 m and 27 m depth respectively. Total sulfide ranged from 0.33 to 32.0 µg/l and the mean at 27 m was significantly higher than 0.5 m depth. Multiple linear regression indicates that BOD 5 was the only significant predictor of total sulfide. This study shows that sulfide was much lower than the lethal level and it would only be unhealthy for the caged fish if there were upwelling or mixing where lower DO water with toxic sulfide at and below 14 m depth were to be brought to the culture zone.

segments the crop protection chemicals market with currant trends and forecasting of the revenues for herbicides, fungicides and insecticides. It also identifies the driving and restraining factors for the crop protection chemicals market with analysis of drivers, opportunities and challenges. The market segmented and revenues are forecasted on the basis of major countries such as U.S., Canada and Brazil. Further, the market is segmented and revenues are forecasted on the basis of product types and crop types.

h i g h l i g h t s Biohydrogen production using coffee mucilage and swine manure was achieved. C/N ratio around 50 could support the increase in organic load keeping stability. Repetitive batch cultivation is useful to detect changes in the pathway. Butyric and acetic pathways are the main routes in biohydrogen production.

This paper aims to provide a bibliometric analysis of publication trends on the themes of biomass and bioenergy worldwide. A wide range of studies have been performed in the field of the usage of biomass for energy production, in order to contribute to the green transition from fossil fuels to renewable energies. Over the past 20 years (from 2000 to 2019), approximately 10,000 articles have been published in the "Agricultural and Biological Sciences" field on this theme, covering all stages of production-from the harvesting of crops to the particular type of energy produced. Articles were obtained from the SCOPUS database and examined with a text mining tool in order to analyze publication trends over the last two decades. Publications per year in the bioenergy theme have grown from 91 in 2000 to 773 in 2019. In particular the analyses showed how environmental aspects have increased their importance (from 7.3% to 11.8%), along with studies related to crop conditions (from 10.4% to 18.6%). Regarding the use of energy produced, growing trends were recognized for the impact of biofuels (mentions moved from 0.14 times per article in 2000 to 0.38 in 2019) and biogases (from 0.14 to 0.42 mentions). Environmental objectives have guided the interest of researchers, encouraging studies on biomass sources and the optimal use of the energy produced. This analysis aims to describe the research evolution, providing an analysis that can be helpful to predict future scenarios and participation among stakeholders in the sector.

Fatty acid metabolism is an attractive route to produce liquid transportation fuels and commodity oleochemicals from renewable feedstocks. Recently, genes and enzymes, which comprise metabolic pathways for producing fatty acid-derived compounds (e.g. esters, alkanes, olefins, ketones, alcohols, polyesters) have been elucidated and used in engineered microbial hosts. The resulting strains often generate products at low percentages of maximum theoretical yields, leaving significant room for metabolic engineering. Economically viable processes will require strains to approach theoretical yields, particularly for replacement of petroleum-derived fuels. This review will describe recent progress toward this goal, highlighting the scientific discoveries of each pathway, ongoing biochemical studies to understand each enzyme, and metabolic engineering strategies that are being used to improve strain performance.

The aim of this paper is to understand and to model the environmental performance of biodiesel
produced by various Greek raw materials under current conditions. Three energy crops (rapeseed,
sunflower and soybean) have been studied, with regard to their levels of biodiesel productivity.
Throughout the entire process, current Greek climatic conditions and cultivation parameters have been
taken into account. At the stage of assessment, we conclude that the environmental impacts per crop
area indicate that soybean has the lowest environmental impacts. However, by assessing the results per
quantity of produced biodiesel, the crop with the minimum environmental impacts is sunflower. This
paper shows that environmental benefits from biodiesel have better results, compared to conventional
diesel, thus leading to the conclusion that it is feasible to succeed improved environmental performance.

The isolation of lipid-rich autochthonous strains of microalgae is a crucial stage for the development of a microalgae-based biofuel production plant, as these microalgae already have the necessary adaptations to withstand competition, predation and the temperatures observed at each production site. This is particularly important in extreme climates such as in Saudi Arabia. Resorting to fluorescence activated cell sorting (FACS) we screened for and isolated several microalgal strains from samples collected from the Red Sea. Relying on the fluorescence of BODIPY 505/515 (4,4-difluoro-1,3,5,7tetramethyl-4-bora-3a,4a-diazasindacene) and growth performance, four promising candidates were identified and the total lipid content and fatty acid profile was assessed for biofuels production. Selected isolates were classified as chlorophytes, belonging to three different genera: Picochlorum, Nannochloris and Desmochloris. The lipid contents were assessed microscopically by means of BODIPY 505/515-associated fluorescence to detect

Background Pretreatment is a critical step in the conversion of lignocellulose to fermentable sugars. Although many pretreatment processes are currently under investigation, none of them are entirely satisfactory in regard to effectiveness, cost, or environmental impact. The use of hydrogen peroxide at pH 11.5 (alkaline hydrogen peroxide (AHP)) was shown by Gould and coworkers to be an effective pretreatment of grass stovers and other plant materials in the context of animal nutrition and ethanol production. Our earlier experiments indicated that AHP performed well when compared against two other alkaline pretreatments. Here, we explored several key parameters to test the potential of AHP for further improvement relevant to lignocellulosic ethanol production. Results The effects of biomass loading, hydrogen peroxide loading, residence time, and pH control were tested in combination with subsequent digestion with a commercial enzyme preparation, optimized mixtures of four commercial ...

Overview of biodiversity in wastewaters Biodiversity is complex in wastewaters, involving micro/macro flora and fauna, and viruses. Interactions among the biota range from mutualism to predation. Community and trophic level cascades dominate the processes. Algal diversity in wastewaters Algae, include both micro and macrophytes. Crucial for the proper functioning of food webs. Cyanophyceae, Chlorophyceae and Bacillariophyceae predominate in most types of wastewaters. Fungi, bacteria and viruses also present with algae, but less investigated. Nutrient removal Chlorella spp.-most investigated alga in wastewaters, especially for N/P sequestration. Consortial approach more effective in nutrient recycling and bioremediation. Algal polycultures, algae-bacteria/algae-fungi consortia mostly utilized. Applications of harvested biomass Feasibility dependent upon type of wastewater, environmental/cultural conditions and end users. Untreated, primary and secondary treated wastewaters evaluated. 18-33% lipid content reported using Chlorella or mixed cultures. Potential for up-scaling and commercialization, but comparison of published work difficult due to heterogeneity in experimentation. Algae cultivation techniques Cultivation of algae in open ponds pose significant challenges. Microalgal communities more robust and productive. High rate algal ponds most advantageous and effective. Advanced Integrated Wastewater Pond Systems and Algal scrubbers gaining significance. Future perspective Algae based wastewater treatment gaining importance globally, especially in developing countries. Environment friendly option, which can reduce CO 2 emissions, generate valuable biomass using domestic, agricultural or industrial wastewaters. Biomass generated can meet energy needs as biocrude/biogas. Biofilms/algal mats ideal for treating low strength wastewaters. Life cycle assessments essential for enhancing economic and environmental sustainability. Cost-effective technologies need to be developed with reduced footprint area for algae cultivation to treat wastewater and produce biomass for biofuel applications.

Microalgae have significant potential to form the basis of the next biofuel revolution. They have high growth and solar energy conversion rates. Furthermore, their osmotolerance, metabolic diversity and capacity to produce large amounts of lipids have attracted considerable interest. Although there are a handful of commercially successful examples of the photoautotrophic mass-culture of algae, these have focused on the production of higher value products (pigments, health-foods etc.). The technical and commercial challenges to develop an economically viable process for biofuels are considerable and it will require much further R&D. In this paper the biological constraints, with a particular focus on strain selection are discussed.

The increase in the price of oil has had an important impact in the rise of food prices in several ways; one of them has been the rise of biofuels whose production has experienced exponential growth in the last decade. In this article we describe what are biofuels, what factors have driven their boom, how positive are their balance in economic, energy and environmental terms, and, especially, what is their impact on food security and what role have played in the food crisis.

The paper reviews the pyrolysis of biomass constituents and possible secondary reactions. Biomass pyrolysis yields mostly liquid and solid fuel, easy to store and transport. Relevant working conditions for experiments and large-scale operation are: (i) biomass particles < 200 mm, (ii) a particle heating rate of at least about 80 K min À1 and (iii) a reactor environment where the internal resistance to heat penetration is smaller than the external resistance to heat transfer (Biot-number, Bi < 1). The circumstances of TGA and DSC experiments meet these requirements and fully determine the reaction kinetics and endothermicity of the pyrolysis reaction. The reaction rate constant and the heat of reaction are essential parameters in the design of a pyrolysis reactor. For most of the biomass species tested, the first order reaction rate constant is large and >0.5 s À1. The heat of reaction ranges from 207 to 434 kJ kg À1. All results tie in with literature data, although the reader is cautioned in using literature data since experiments were not always performed under relevant testing conditions.

Xylanase is an enzyme in high demand for various industrial applications, such as those in the biofuel and pulp and paper Welds. In this study, xylanase-producing microbes were isolated from the gut of the wood-feeding termite at 50°C. The isolated microbe produced thermostable xylanase that was active over a broad range of temperatures (40-90°C) and pH (3.5-9.5), with optimum activity (4,170 § 23.5 U mg ¡1 ) at 60°C and pH 4.5. The enzyme was puriWed using a strong cation exchanger and gel Wltration chromatography, revealing that the protein has a molecular mass of 205 kDa and calculated pI of 5.38. The half-life of xylanase was 6 h at 60°C and 2 h at 90°C. The isolated thermostable xylanase diVered from other xylanases reported to date in terms of size, structure, and mode of action. The novelty of this enzyme lies in its high speciWc activity and stability at broad ranges of temperature and pH. These properties suggest that this enzyme could be utilized in bioethanol production as well as in the paper and pulp industry.

Biomethanation Cookstove Appropriate technology Renewable energy a b s t r a c t Low-cost tubular digesters originally developed in tropical regions have been adapted to the extreme weather conditions of the Andean Plateau (3000e4000 m.a.s.l.). The aim of this study was to characterise biogas production in household digesters located at high altitude, operating under psychrophilic conditions. To this end, two pilot digesters were monitored and field campaigns were carried out in two representative digesters of rural communities.

This paper is confined to the production and physico-chemical characterization of peanut oil biodiesel (POB). An optimum conversion of POB from triglycerides (TD) was achieved by using 1:6 molar ratio (methanol : oil) at 60 o C. Fuel properties of POB were determined and compared with ASTM (American Standard Testing Material). The kinemetic viscosity at 40 o C (eta) of POB (100%) was 5.908, specific gravity 0.918, density at 40 o C (Rho) 0.0992, flash point (FP) 192, pour point (PP) 3 o C, cloud point (CP) 6

Algal biofuels and valuable co-products are being produced in both open and closed cultivation systems. Growing algae in open pond systems may be a more economical alternative, but this approach allows environmental microorganisms to colonize the pond and potentially infect or outcompete the algal “crop”. In this study, we monitored the microbial community of an outdoor, open raceway pond inoculated with a high lipid-producing alkaliphilic alga, Chlorella vulgaris BA050. The strain C. vulgaris BA050 was previously isolated from Soap Lake, Washington, a system characterized by a high pH (approximately 9.8). An outdoor raceway pond (200L) was inoculated with C. vulgaris and monitored for ten days and then the culture was transferred to a 2,000L raceway pond and cultivated for an additional six days. Community DNA samples were collected over the 16-day period in conjunction with water chemistry analyses and cell counts. Universal primers for the SSU rRNA gene sequences for Eukarya, Bacteria, and Archaea were used for barcoded pyrosequence determination. The environmental parameters that most closely correlated with C. vulgaris abundance were pH and phosphate. Community analyses indicated that the pond system remained dominated by the Chlorella population (93% of eukaryotic sequences), but was also colonized by other microorganisms. Bacterial sequence diversity increased over time while archaeal sequence diversity declined over the same time period. Using SparCC co-occurrence network analysis, a positive correlation was observed between C. vulgaris and Pseudomonas sp. throughout the experiment, which may suggest a symbiotic relationship between the two organisms. The putative relationship coupled with high pH may have contributed to the success of C. vulgaris. The characterization of the microbial community dynamics of an alkaliphilic open pond system provides significant insight into open pond systems that could be used to control photoautotrophic biomass productivity in an open, non-sterile environment.

This paper examines the demonization of biofuels in relation to food security and assess whether or not the negativity towards biofuels is justified. We first examine the concept of food security which has been a concern long before the emergence of biofuels. We show that creating food security is more than producing a 'sufficient' volume of food instead that it depends on complex, context dependent, social, economic, political and ecological factors in which growing biofuels. Indeed biofuels is only one of the influencing factors. We would suggest that too much focus on growing biofuels as the identified problem detracts from the underlying causes of food insecurity and hunger.

This article argues that, except in California, environmental justice considerations have not received sufficient attention in climate change policy debates. It explores the environmental justice implications of emerging domestic climate change policies and provides policymakers with specific suggestions on how to integrate environmental justice concerns. The article begins by introducing the environmental justice movement and its central principles, and then