Análisis de la mezcla de alcoholes en motor diésel

Debido a que el futuro del petróleo es incierto, en la búsqueda de los combustibles alternativos se ha encontrado que el alcohol es un fuerte candidato como combustible; los alcoholes inferiores más representativos son el metanol y el etanol, los cuales han demostrado en general baja miscibilidad, por lo que pueden generar una separación de fases al ser mezclados después de un cierto tiempo. La única manera de emplearlos en un motor diésel es mezclándolos con biodiésel o con surfactantes. Por el contrario, los alcoholes superiores tienen características más adecuadas para ser mezclados o empleados en el motor diésel. Por su parte, los éteres son una buena opción cuando se trate de combustión piloto en que se considere emplear combustibles gaseosos como el biogás o el syngas en motor diésel dual. En esta investigación se exploran las alternativas que existen para mejorar las características del alcohol, por ejemplo, mezclarlo con biodiésel, biogás, agua o nanopartículas, y también se analizan las emisiones que se producen con las mezclas generadas. El objetivo es indagar las diferencias entre los alcoholes inferiores y los alcoholes superiores de cadena larga, así como las mezclas que se pueden generar para mejorar el rendimiento del motor. Los resultados afirman que los alcoholes de cadena larga tienen mejores propiedades físico-químicas que los alcoholes de cadena corta; el butanol es el único combustible que puede ser transportado y almacenado en las mismas redes de tuberías actuales de los productos petroleros existentes. También se cuenta con la opción de usar el alcohol como combustible piloto en un motor diésel dual; esto puede servir para aplicar una enorme variedad de combustibles tanto líquidos como gaseosos, lo cual hace que las opciones en su aplicación se incrementen. Como conclusión, se recomienda explorar nuevas mezclas analizando sus sinergias con varios combustibles alternativos. La posibilidad de realizar el diesterol-BED genera resultados muy alentadores, por lo que se recomienda seguir haciendo análisis sobre esa línea para encontrar la mezcla óptima.

As the future of oil is uncertain and in the search for alternative fuels, it has been found that alcohol is a strong candidate as a fuel. The most representative lower alcohols are methanol and ethanol, which have generally demonstrated low miscibility so that they can generate phase separation when mixed after a certain period of time. The only way to use them in a diesel engine is to mix them with biodiesel or surfactants. By contrast, higher alcohols have more suitable characteristics to be mixed or used in the diesel engine. In the case of ethers they are a good option when it comes to pilot combustion considering using gaseous fuels such as biogas or syngas in dual diesel engine. This research explores the alternatives that exist to improve the characteristics of alcohol as it can be mixed with biodiesel, biogas, water or nanoparticles and also analyzes the emissions that are generated with the mixtures. The aim of this research is to explore the differences between lower alcohols and long chain upper alcohols, as well as the mixtures that can be generated to improve engine performance. The results of this research claim that long-chain alcohols have better physico-chemical properties than short-chain alcohols, butanol being the only fuel that can be transported and stored in the same current pipeline networks of existing oil products. There is also the option to use alcohol as a pilot fuel in a dual diesel engine. The latter can be used to apply a huge variety of both liquid and gaseous fuels, this makes the options in its application increase. As a conclusion of this work, it is recommended to explore new mixtures analyzing their synergies with various alternative fuels. The possibility of performing diesterol-BED generates very encouraging results, therefore it is recommended to continue to perform analyses on that line to find the optimal mixture.

Na busca por combustíveis alternativos porque o futuro do petróleo é incerto, verificou-se que o álcool é um forte candidato como combustível, onde os álcoois inferiores mais representativos são o metanol e o etanol, que, em geral, demonstraram baixa miscibilidade, de modo que podem gerar separação de fase quando misturadas após um determinado período de tempo, a única forma de as utilizar num motor diesel é misturá-las com biodiesel ou tensioactivos, pelo contrário, os álcoois superiores têm características mais adequadas para serem misturados ou utilizados no motor diesel, no caso dos éteres, são uma boa opção quando se trata de combustão piloto, considerando a utilização de combustíveis gasosos, como biogás ou gás de síntese em motores a diesel duplos, esta pesquisa explora as várias alternativas que existem para melhorar as características do álcool, pois pode ser misturado com biodiesel, biogás, água ou nanopartículas e também analisa as emissões que são geradas com as misturas geradas, O objetivo desta pesquisa é explorar as diferenças entre álcoois inferiores e álcoois superiores de cadeia longa, bem como as misturas que podem ser geradas para melhorar o desempenho do motor. Os resultados desta pesquisa afirmam que os álcoois de cadeia longa têm melhores propriedades físico-químicas do que os álcoois de cadeia curta, sendo o butanol o único combustível que pode ser transportado e armazenado nas mesmas redes de gasodutos atuais que os produtos petrolíferos existentes, há também a opção de usar álcool como combustível piloto em um motor diesel duplo, Este último pode ser usado para aplicar uma enorme variedade de combustíveis líquidos e gasosos, o que aumenta as opções em sua aplicação. Como conclusão deste trabalho recomenda-se explorar novas misturas analisando suas sinergias com vários combustíveis alternativos, a possibilidade de realizar diesterol-BED gera resultados muito encorajadores, portanto, recomenda-se continuar a realizar análises nessa linha para encontrar a mistura ideal.

Bioethanol Production from Various Lignocellulosic Materials by Encapsulated Saccharomyces cerevisiae NCIM 3095

Bioethanol has a greater promise for environmental safety and energy security than fossil fuels. The alternate source required to meet the fuel's requirements can be provided by bioethanol. Untapped sugar-rich sources, like cellulose-rich household wastes, industrial wastes, and agricultural wastes, can all be used to make bioethanol at a minimal cost. The study's objective was to determine whether saccharomyces cerevisiae cells from the encapsulated NCIM 3095 strain of Saccharomyces cerevisiae could be used to make low-cost ethanol from a variety of lignocellulosic wastes, including newspaper, banana leaves, gram straw, soybean straw, and cow dung. To reduce bacterial contamination and serve as an external growth stimulator, benzathine penicillin G and ammonium sulfate were added to each sample broth containing calcium alginate-encapsulated yeast cells. The samples were fermented for ten days. The ethanol content was evaluated every three days. The largest yield of bioethanol was produced by soybean straw (10.0%), while the lowest was by cow dung (4.0%).

Metagenomics approach to identify lignocellulose-degrading enzymes in the gut microbiota of the Chinese bamboo rat cecum

BACKGROUND: Lignocellulose is considered a renewable organic material, but the industrial production of biofuel from lignocellulose is challenging because of the lack of highly active hydrolytic enzymes. The guts of herbivores contain many symbiotic microorganisms that have evolved to hydrolyze plant lignocellulose. Chinese bamboo rats mainly consume high-fiber foods, indicating that some members of the intestinal tract microbiota digest lignocellulose, providing these rats with the energy required for growth. RESULTS: Here, we used metagenomics to analyze the diversity and functions of the gut microbiota in Chinese bamboo rats. We identified abundant populations of lignocellulose-degrading bacteria, whose main functions involved carbohydrate, amino acid, and nucleic acid metabolism. We also found 587 carbohydrate-active enzyme genes belonging to different families, including 7 carbohydrate esterase families and 21 glycoside hydrolase families. The glycoside hydrolase 3, glycoside hydrolase 1, glycoside hydrolase 43, carbohydrate esterase 4, carbohydrate esterase 1, and carbohydrate esterase 3 families demonstrated outstanding performance. CONCLUSIONS: The microbes and enzymes identified in our study expand the existing arsenal of proficient degraders and enzymes for lignocellulosic biofuel production. This study also describes a powerful approach for targeting gut microbes and enzymes in numerous industries.

Venturi: dispositivo de cavitação hidrodinâmica para acelerar a síntese de biodiesel / Venturi: hydrodynamic cavitation device to accelerate biodiesel synthesis

RESUMO O objetivo deste trabalho foi avaliar o potencial do Venturi para a síntese de biodiesel a partir de óleo comestível residual em rota metílica. Para tanto, foi construído em escala de laboratório um aparato experimental constituído de um tanque de 5,2 L e um dispositivo Venturi projetado para produzir o fenômeno de cavitação. A produção de biodiesel foi avaliada em três diferentes pressões de entrada do Venturi: 4,4; 2,9; e 1,4 bar. Os teores de ésteres metílicos foram determinados por cromatografia gasosa. O tempo de síntese de 5,2 L de biodiesel, com o Venturi, foi de 23,2 segundos (ou 4,5 segundos por litro de biodiesel produzido), o que equivale a um único ciclo de passagem pelo sistema a pressão máxima (4,4 bar). Nessa condição, o rendimento dos teores de ésteres foi superior a 98%. Não há na literatura outro caso de síntese tão rápida como a encontrada neste trabalho. A caracterização do biodiesel mostrou que os parâmetros viscosidade cinemática, índice de acidez, ponto de entupimento a frio e massa específica estão dentro dos limites estabelecidos pela Agência Nacional de Petróleo. A comparação com outros estudos da literatura mostrou que o Venturi é superior às placas de orifício na síntese de biodiesel.

Abstract The objective of this work was to evaluate the potential of Venturi in the synthesis of biodiesel from residual edible oil in a methyl route. For this purpose, an experimental apparatus consisting of a 5.2 L tank and a Venturi device designed to produce the cavitation phenomenon was constructed in laboratory scale. Biodiesel production was evaluated at three different Venturi inlet pressures: 4.4; 2.9; and 1.4 bar. Methyl esters contents were determined by gas chromatography. Biodiesel synthesis time with the Venturi device was 23.2 seconds (or 4.5 seconds per liter of biodiesel produced), which is equivalent to a single cycle of the system at maximum pressure (4.4 bar). In this condition, the yield of the ester contents was greater than 98%. There is no other case of synthesis as fast as that found in this work. The biodiesel characterization showed that the parameters kinematic viscosity, acidity index, cold clogging point, and specific mass are within the limits established by National Agency of Petroleum Natural Gas and Biofuels (Agência Nacional de Petróleo). The use of Venturi, as a cavitation device, was shown to be more efficient in biodiesel synthesis than other devices, such as orifice plates.

Determination of Bioethanol Production from Apricot (Prunus armeniaca) Pomace

Abstract Fruit juice industry generates massive amount of lignocellulosic by-products annually which are excellent raw materials for bioethanol production. In the current study, bioethanol production from apricot (Prunus armeniaca) pomace by Kluyveromyces marxianus was investigated for the first time. Some key parameters for fermentation such as pretreatment methods, biomass and cellulase loading and time, were optimized. Kluyveromyces marxianus produced 30.09 g/L ethanol in the 20% washed apricot pomace and 120 FPU/g cellulose enzyme loading. The highest theoretical yield and Y P/S values were also observed as 94.7% and 0.50 g/g, respectively, when 15 FPU/g cellulose enzyme was used. These results depict that apricot pomace is a promising feedstock for bioethanol production.

Metabolic characterization and oil profile of sunflower cultivars cultivated with increasing nitrogen doses / Caracterização metabólica e perfil do óleo de cultivares de girassol cultivados sob doses crescentes de nitrogênio

Sunflower (Helianthus annuus L.) has great economic importance due to its oil yield and quality. Among the factors influencing these parameters, nitrogen fertilization stands out. In this study we evaluated the effect of different N-urea doses (0,10,30,50,90,130 kg N-urea ha-1) at planting and 30 days after emergency on soluble fractions, oil profile and yield of three sunflower cultivars (BRS324, Catissol 01and Neon). Plants were harvested at the flowering stage for metabolic study, and at the end of the cycle for oil extraction and characterization. The Catissol 01 genotype presented the highest N-NO3- accumulation capacity, mainly in the stem. The Neon genotype presented the highest achene production at 30 and 50 kg N ha-1. Oleic oil had the highest yield, with the Catissol 01 and Neon cultivar standing out. Among the cultivars, Catissol 01 is economically more suitable for biofuel production, when cultivated at 50 kg N ha-1 since higher N doses did not result in increased oil yield.

O girassol é uma espécie com importante valor econômico pela qualidade e rendimento de óleo. Entre os fatores que influenciam esses parâmetros se destaca a fertilização nitrogenada. Este trabalho avaliou o efeito de doses crescentes de N-uréia (0, 10, 30, 50, 90, 130 kg de N-Uréia ha-1 aplicadas no plantio e aos 30 dias após a emergência) sobre as frações solúveis, rendimento e perfil do óleo de três genótipos de girassol (BRS324, Neon e Catissol 01). As plantas foram coletadas no estádio de floração para o estudo metabólico e ao final do ciclo para a extração e caracterização de óleo. O genótipo Catissol 01 apresentou maior capacidade de acúmulo de N-NO3-, preferencialmente no caule. A maior produção de óleo por planta foi observada no BRS324, nas doses entre 30 e 50 kg N ha-1, embora o genótipo Neon tenha apresentado a maior produção de aquênios. O ácido oléico foi o de maior rendimento com destaque para os genótipos Catissol 01 e Neon. Dentre os genótipos avaliados, o Catissol 01 é economicamente mais indicado para a produção de óleo destinada ao biocombustível, quando cultivado com a dose de 50 kg N ha-1, pois doses superiores de N não resultam em aumento na produção de óleo.

Emission Characteristics of Methyl Ester of Rice Bran Oil Blends with Ethanol in CI Engine

Increasing demand and rapid depletion of fossil fuels have together prompted the researchers of many countries to look for alternate renewable fuels. This study is an attempt to test the feasibility of rice bran oil as fuel in C. I. engine in its original and in its refined form. It is generally produced from rice bran which is a by-product produced during paddy processing. Its viscosity though relatively higher than diesel can be reduced by natural sedimentation process. In this attempt, the performance and emission characteristics of rice bran oil and its refined form were studied and compared with diesel by employing them as a fuel in a single cylinder, direct injection, 4.4 KW, air cooled diesel engine. The performance characteristics revealed that the brake thermal efficiency of the rice bran oil was higher than its refined form and were marginally lower than that of diesel. Emission measurements were carried out using MRU Delta 1600L gas analyzer and the soot concentration was measured with AVL smoke meter. It was found that though blends of rice bran oil with ethanolexhibited greater soot concentration characteristics than rice bran oil and diesel at all loads, it exhibited desirable characteristics for other emissions such as lower CO, HC, NOx emissions and lower exhaust gas temperatures with increasing load.

Composição nutricional e valores energéticos determinados com frangos de corte de coprodutos do processamento do etanol de milho / Nutritional composition and energy values determined with broilers of co-products from the processing of corn ethanol

It was determined by the total collection of excreta method, with broilers from 22 to 32 days of age, the coefficients of apparent metabolism of dry matter, crude protein and crude energy and apparent metabolizable energy corrected for zero nitrogen balance (AMEn) of the ethanol co-products of corn: acid oil and dried distillery grains with soluble (DDGS). The DDGS and corn acid oil presented nutritional metabolization coefficients ranging from 43 to 83% and AMEn equal 2393.5 and 7859.2kcal/kg respectively, and may be food alternatives to soybean meal and soybean oil.(AU)

Effects of weed management and plant arrangements on yield index of sweet sorghum / Eefeito do manejo de plantas daninhas e arranjo de plantas nos índices de produtividade do sorgo sacarino

Sweet sorghum is currently an important alternative for ethanol production in sugar cane off-season. In this study was to evaluate the effects of plant arrangements and the application of atrazine and S-metolachlor on growth and productivity of sweet sorghum. An experiment was conducted in randomized block design and, arranged in split plots with four repetitions. Plots consisted of spacing (0.25 m, 0.45 m 0.45-0.45-0.90 m) and sub-plots of weed control methods - atrazine (2000 g ha-1), atrazine + S-metolachlor (2000 + 720 g ha-1), atrazine + S-metolachlor (2000 + 960 g ha-1), atrazine + S-metolachlor (2000 + 1200 g ha-1), atrazine + S-metolachlor (2000 + 1440 g ha-1). Besides that, manual hoeing control was added. The intoxication of sorghum plants and weed control was evaluated at 7, 14 e 28 days after herbicides application (DAA). Plant height, stem diameter, total fresh matter, juice mass and total soluble solids (°Brix) were evaluated at 120 days after crop emergence (DAE). There was no interaction between the factors spacings and control method for variables total matter fresh (TMF), height (H), stem diameter (D), juice mass (JM), and Brix. Application of the mixture (atrazine + S-metolachlor) in the highest doses reduced total fresh matter and °Brix. The spacing of 0.25 m provided the highest productivity of fresh matter, juice mass and increased the °Brix. The application of mixture (atrazine + S-metolachlor) controlled 90% of the weeds at 28 days after application. The increasing in doses of S-metolachlor elevates the intoxication in sorghum plants. The mixture (atrazine + S-metolachlor) has a potential for use in weed control in sweet sorghum, but at doses below 960 g ha-1 of S-metolachlor.

O objetivo desse trabalho foi avaliar os efeitos de arranjos de plantas e dos herbicidas atrazine e S-metolachlor sobre o crescimento e a produtividade do sorgo sacarino. O experimento foi realizado no delineamento em blocos casualizados, com quatro repetições. Os tratamentos foram dispostos em esquema de parcelas subdivididas. Nas parcelas avaliaram-se os espaçamentos entrelinhas (0,25 m, 0,45 m e 0,45-0,45-0,90 m) e nas subparcelas os métodos de controle das plantas daninhas: atrazine (2000 g ha-1), atrazine + S-metolachlor (2000 + 720 g ha-1), atrazine + S-metolachlor (2000 + 960 g ha-1), atrazine + S-metolachlor (2000 + 1200 g ha-1), atrazine + S-metolachlor (2000 + 1440 g ha-1), capina manual e ausência de controle. Aos 7, 14 e 28 dias após a aplicação dos herbicidas foi avaliado a intoxicação das plantas de sorgo e o nível de controle de plantas daninhas na cultura. Aos 120 dias após a emergência da cultura avaliou-se altura de plantas, diâmetro de colmo, massa fresca total, massa de caldo e o teor de sólidos solúveis totais (Brix). Não houve interação entre os fatores espaçamentos e o método de controle para as variáveis massa fresca total (TMF), altura (H), diâmetro do caule (D), peso do suco (JM) e Brix. O controle das plantas daninhas e a intoxicação visual do sorgo aumentaram linearmente com o incremento das doses do S-metolachlor. O crescimento da cultura e os teores de Brix foram reduzidos pela aplicação da associação entre atrazine + S-metolachlor. A escolha do espaçamento de entrelinha influenciou nos componentes de rendimento da cultura. Conclui-se que, o espaçamento de 0,25 m de entrelinhas proporcionou maior produtividade de matéria fresca e de Brix do caldo. A associação entre atrazine e S-metolachlor tem potencial para o uso no controle de plantas daninhas em sorgo sacarino, em doses abaixo de 960 g ha-1 de S-metolachlor.

Process conditions for a rapid in situ transesterification for biodiesel production from oleaginous yeasts

BACKGROUND: Microbial oils produced by diverse microorganisms are being considered as alternative sources of triglycerides for biodiesel production. However, the standalone production of biodiesel from microorganisms is not currently economically feasible. In case of yeasts, the use of low-value nutrient sources in microbial production and the implementation of cost-efficient downstream processes could reduce costs and make microbial lipids competitive with other commodity-type oils in biodiesel production. Industrial biodiesel synthesis from oleaginous seeds is currently based on a multistep process. However, a simple process called in situ transesterification (ISTE), which takes place within the biomass without a previous lipid extraction step, is receiving increasing interest. In this work, the optimal conditions for an ISTE process to obtain biodiesel from previously selected oleaginous yeast (Rhodotorula graminis S1/S2) were defined using the response surface methodology (RSM). RESULTS: Using the RSM approach, the optimal conditions for the maximum yield with minimum reaction time included a methanol-to-biomass ratio of 60:1, 0.4 M H2SO4, and incubation at 70°C for 3 h. The optimized in situ process yield was significantly higher (123%) than that obtained with a two-step method in which fatty acids from saponifiable lipids were first extracted and then esterified with methanol. The composition of the fatty acid methyl ester mixture obtained from R. graminis S1/S2 by ISTE met Uruguayan standards for biodiesel. CONCLUSION: The characteristics achieved by the optimized method make microbial oil a potential alternative for biodiesel production from yeast at an industrial scale.

Bioethanol from Microalgal Biomass: A Promising Approach in Biorefinery

Abstract The development of new technologies which increase the production of biofuel without directly compete with food production is required. Microalgal biomass has recently been in the highlight. The role of this biomass is here discussed within the concept of biorefinery and industrial sustainability of bioethanol production. The process of cultivation in order to accumulate around 50% of carbohydrates in the biomass (dry weight) and the importance of water and nutrient recycling are reviewed. Saccharification of biomass using enzymes or acids and alternative processes such as hydrothermal liquefaction and flash hydrolysis are addressed. Since the main monosaccharide in microalgal biomass is glucose, high rates of hydrolysis and fermentation were, generally, achieved (more than 80% of the efficiency as a sum of these two processes). Anaerobic digestion to treat vinasse and the recycling of CO2 from the ethanolic fermentation and biogas could increase the process sustainability. Alternative techniques for the concentration of bioethanol from fermentation broth and for the optimization of fuel transportation are mentioned. Finally, the advantage of using microalgae rather than other sources is estimated with reference to the production rate, even though the cultivation costs are still high.

Effectiveness of a micronutrient delivery system fertilizer in jatropha plants is related to enhanced photosynthesis, gas exchange and biomass allocation / Eficácia de um sistema de fornecimento de micronutrientes em plantas de jatropha está relacionado com incrementos na fotossíntese, troca gasosa e alocação de biomassa

This study aimed at comparing the growth and physiological changes in Jatropha curcas L. (jatropha or physic nut) young plants fertilized or not with a commercial product based on a micronutrient delivery system (MDS), under different doses of NPK. Measurements of growth, chlorophyll content, and leaf gas exchange were performed in the greenhouse, where plants were arranged in a split-split plot design. Plants were grown for 120 days in 3.9 L pots containing local soil, with or without MDS (main plot), combined with NPK doses (0; 1.8; 4.7 and 7.4 g L-1) in subplots. Dose-response curves showed that most variables were positively responsive to NPK doses in plants growing without MDS, whereas slight responses or even opposite behavior was observed in MDS-fertilized plants. MDS application under low NPK doses resulted in higher biomass allocation in leaves and roots, increases in number of leaves and chlorophyll content, plant height, stem diameter, shoot and root dry weight, stomatal conductance, photosynthesis, leaf transpiration, and water use efficiency, as well as decreases in intercellular CO2 in the leaf and vapor-pressure deficit. The enhanced biomass allocation, photosynthesis and gas exchange in MDS-supplemented plants indicates the relevant role played by this fertilizer in jatropha metabolism, resulting in more vigorous plants.

Este estudo teve como objetivo comparar o crescimento e as mudanças fisiológicas em plantas jovens de Jatropha curcas L. (pinhão manso), fertilizadas ou não, com um produto comercial baseado em um sistema de fornecimento de micronutrientes (MDS), sob diferentes doses de NPK. Medidas de crescimento, teor de clorofila e troca gasosa foliar foram realizados em casa de vegetação, onde as plantas foram arranjadas em um delineamento de blocos casualizados com parcela subdividida. As plantas foram cultivadas por 120 dias em potes de 3,9 L contendo solo local, com ou sem MDS (parcela principal), combinado com doses de NPK (0; 1,8; 4,7 e 7,4 g L-1) nas subparcelas. Curvas doseresposta mostraram que a maioria das variáveis responderam positivamente às doses de NPK em plantas crescendo sem MDS, enquanto respostas fracas ou mesmo comportamento oposto foi observado em plantas fertilizadas com MDS. A aplicação de MDS em doses baixas de NPK resultaram em maior alocação de biomassa nas folhas e raízes, aumento no número de folhas e teor de clorofila, altura da planta, diâmetro do caule, pesos secos da parte aérea e raiz, condutância estomatal, fotossíntese, transpiração foliar e eficiência no uso da água, bem como na redução do CO2 intercelular na folha e déficit de pressão de vapor. O aumento na alocação de biomassa, fotossíntese e troca gasosa em plantas suplementadas com MDS indica o papel relevante deste fertilizante no metabolismo de pinhão manso, resultando em plantas mais vigorosas.

Chemical pretreatment of Arundo donax L. for second-generation ethanol production

Background: Pretreatment of lignocellulosic biomass is essential for using it as a raw material for chemical and biofuel production. This study evaluates the effects of variables in the chemical pretreatment of the Arundo biomass on the glucose and xylose concentrations in the final enzymatic hydrolysate. Three pretreatments were tested: acid pretreatment, acid pretreatment followed by alkaline pretreatment, and alkaline pretreatment. Results: The amounts of glucose and xylose released by the enzymatic hydrolysis of the Arundo biomass obtained from acid pretreatment ranged from 6.2 to 19.1 g/L and 1.8 to 3.1 g/L, respectively. The addition of alkaline pretreatment led to a higher yield from the enzymatic hydrolysis, with the average glucose concentration 3.5 times that obtained after biomass hydrolysis with an acid pretreatment exclusively. The use of an alkaline pretreatment alone resulted in glucose and xylose concentrations similar to those obtained in the two-step pretreatment: acid pretreatment followed by alkaline pretreatment. There was no significant difference in 5-hydroxymethylfurfural, furfural, or acetic acid concentrations among the pretreatments. Conclusion: Alkaline pretreatment was essential for obtaining high concentrations of glucose and xylose. The application of an alkaline pretreatment alone resulted in high glucose and xylose concentrations. This result is very significant as it allows a cost reduction by eliminating one step.

Advances in enzyme bioelectrochemistry

ABSTRACT Bioelectrochemistry can be defined as a branch of Chemical Science concerned with electron-proton transfer and transport involving biomolecules, as well as electrode reactions of redox enzymes. The bioelectrochemical reactions and system have direct impact in biotechnological development, in medical devices designing, in the behavior of DNA-protein complexes, in green-energy and bioenergy concepts, and make it possible an understanding of metabolism of all living organisms (e.g. humans) where biomolecules are integral to health and proper functioning. In the last years, many researchers have dedicated itself to study different redox enzymes by using electrochemistry, aiming to understand their mechanisms and to develop promising bioanodes and biocathodes for biofuel cells as well as to develop biosensors and implantable bioelectronics devices. Inside this scope, this review try to introduce and contemplate some relevant topics for enzyme bioelectrochemistry, such as the immobilization of the enzymes at electrode surfaces, the electron transfer, the bioelectrocatalysis, and new techniques conjugated with electrochemistry vising understand the kinetics and thermodynamics of redox proteins. Furthermore, examples of recent approaches in designing biosensors and biofuel developed are presented.

Isolation of fungi from dung of wild herbivores for application in bioethanol production

ABSTRACT Producing biofuels such as ethanol from non-food plant material has the potential to meet transportation fuel requirements in many African countries without impacting directly on food security. The current shortcomings in biomass processing are inefficient fermentation of plant sugars, such as xylose, especially at high temperatures, lack of fermenting microbes that are able to resist inhibitors associated with pre-treated plant material and lack of effective lignocellulolytic enzymes for complete hydrolysis of plant polysaccharides. Due to the presence of residual partially degraded lignocellulose in the gut, the dung of herbivores can be considered as a natural source of pre-treated lignocellulose. A total of 101 fungi were isolated (36 yeast and 65 mould isolates). Six yeast isolates produced ethanol during growth on xylose while three were able to grow at 42 °C. This is a desirable growth temperature as it is closer to that which is used during the cellulose hydrolysis process. From the yeast isolates, six isolates were able to tolerate 2 g/L acetic acid and one tolerated 2 g/L furfural in the growth media. These inhibitors are normally generated during the pre-treatment step. When grown on pre-treated thatch grass, Aspergillus species were dominant in secretion of endo-glucanase, xylanase and mannanase.

Preemergence herbicides on weed control in elephant grass pasture / Controle de plantas daninhas em pastagem de capim-elefante com herbicidas pré-emergentes

ABSTRACT Elephant grass (Pennisetum purpureum Schum.) is an important forage crop that has been proposed as a potential feedstock for bioenergy production. However, weed interference is a major factor limiting elephant grass production. Field experiments were conducted in 2014 and 2015 to evaluate preemergence herbicides for selective weed control in an elephant grass pasture. Herbicide treatments included atrazine + S-metolachlor, atrazine + simazine, ametryn, ethoxysulfuron, S-metolachlor, diuron + hexazinone, sulfentrazone, imazethapyr, and atrazine at label use rates. Weedy and weed-free treatments were included. Atrazine + S-metolachlor, atrazine + simazine, ametryn, ethoxysulfuron, S-metolachlor, sulfentrazone, and atrazine did not cause phytotoxicity on elephantgrass 35 days after treatment (DAT). However, diuron + hexazinone and imazethapyr were the most phytotoxic on elephantgrass, resulting in 81 and 70% phytotoxicity in 2014, and 7 and 6% phytotoxicity in 2015 respectively 35 DAT. All treatments provided effective weed control (>81%) with the exception of ethoxysulfuron (0 and 11% in 2014 and 2015, respectively), and atrazine (59% in 2014). These results show that atrazine + S-metolachlor, atrazine + simazine, ametryn, ethoxysulfuron, S-metolachlor, sulfentrazone, and atrazine were selectives when applied in preemergence in elephant grass pasture.

RESUMO O capim-elefante (Pennisetum purpureum Schum.) é uma planta forrageira importante que tem sido proposta como matéria-prima potencial para a produção de bioenergia. No entanto, a interferência das plantas daninhas é um fator limitante na produção do capim-elefante. Experimentos de campo foram realizados em 2014 e 2015 para avaliar herbicidas aplicados em condições de pré-emergência para o controle seletivo de plantas daninhas em pastagem de capim-elefante. Os tratamentos herbicidas incluíram atrazine + S-metolachlor, atrazine + simazine, ametryn, ethoxysulfuron, S-metolachlor, diuron + hexazinone, sulfentrazone, imazethapyr e atrazine em doses normalmente recomendadas no rótulo. Foram incluídas as testemunhas sem capina e capinadas. Atrazine + S-metolachlor, atrazine + simazine, ametryn, ethoxysulfuron, S-metolachlor, sulfentrazone e atrazine não causaram fitotoxicidade em capim-elefante aos 35 dias após os tratamentos (DAT). No entanto, diuron + hexazinone e imazethapyr foram os mais fitotóxicos ao capim-elefante, resultando em 81 e 70% de fitotoxicidade em 2014, e 7 e 6% em 2015, aos 35 DAT, respectivamente. Todos os tratamentos de controle de plantas daninhas foram eficazes (> 81%) com a exceção de ethoxysulfuron (0 e 11%, em 2014 e 2015, respectivamente) e atrazine (59%, em 2014). Estes resultados mostram que os herbicidas atrazine + S-metolachlor, atrazine + simazine, ametryn, ethoxysulfuron, S-metolachlor, sulfentrazone e atrazine foram seletivos quando aplicados em pré-emergência em pastagem de capim-elefante.

Performance of sweet potato clones for starch and ethanol in three regions of the state of Sergipe, Brazil / Desempenho de clones de batata doce para amido e etanol em três regiões do estado de Sergipe, Brasil

Sweet potato (Ipomoea batatas L.) is a species that belongs to the family Convolvulaceae, and is originated from Central America and South America. As the growing conditions have great influence on the crop, the determination of harvesting time may vary with the cultivar, the growing region, or with the type of consumption (in natura or industrial). The aim of this work was to evaluate the performance of Ipomoea batatas L. clones, cultivated in three regions in the state of Sergipe, for starch and ethanol production. Thirty-one sweet potato clones grown in three municipalities of the state of Sergipe were tested in a randomized block design. The following variables were analyzed: root dry matter content (RDMC), root starch content (SC), starch yield (SY), ethanol yield (EY), and ethanol yield per ton of root (EYR). EY values ranged from 5910.39 to 8516.12 L ha-1; from 5141.85 to 6937.63 L ha-1; and from 5829.62 to 8211.77 L ha-1 in the municipalities of São Cristóvão, Malhador, and Canindé de São Francisco, respectively, for clones IPB-075 and IPB-087 and cultivar Palmas. Estimates of heritability (h2) were above 50%. The values of the ratio between the coefficient of genetic variation (CVg) and the coefficient of environmental variation (CVe) for RDMC, SC, and EYR were high.

A batata doce é uma espécie pertencente a família Convolvulaceae, originária da América Central e do Sul. As condições de cultivo têm grande influência na produção, sendo que a determinação do tempo de colheita varia de acordo com a cultivar, com a região de cultivo e com a forma de consumo (in natura ou industrial). O objetivo deste trabalho foi avaliar o desempenho de clones de batata-doce (Ipomoea batatas L.) cultivados em três regiões do estado de Sergipe para produção de amido e etanol. Testou-se, em delineamento de blocos casualizados, 31 genótipos de batata doce em três município do Estado de Sergipe. As características analisadas foram: teor de matéria seca de raízes (RDMC), teor de amido nas raízes (SC), rendimento de raízes (SY), rendimento de etanol (EY) e rendimento de etanol por tonelada de raiz (EYR). Os valores de EY variaram de 5910,39 a 8516,12 L.ha-1, de 5141,85 a 6937,63 L ha-1 e de 5829,62 a 8211,77 L ha-1 para São Cristóvão, Malhador e Canindé de São Francisco, respectivamente, para os clones IPB-075 e IPB-087 e a cultivar Palmas. As estimativas de herdabilidade (h2) foram superiores a 50 %. Os valores da razão entre o coeficiente de variação genotípica e o ambiental para RDMC, SC, e EYR foram altos.

Screening of endophytic fungi for biofuel feedstock production using palm oil mill effluent as a carbon source

Aims: Palm oil mill effluent (POME) is a major agricultural waste product of Malaysia. The aim of this study was to identify endophytic fungi capable of producing biofuel feedstock utilizing POME. Methodology and results: Endophytes were isolated from the Nipah palm tree, Nypa fruticans, and exposed to different POME concentrations (25%, 50% and 75%), with and without the addition of nutrients. The utilization of glucose was measured using the Dinitrosalicylic Acid assay whereas the lipid content in the fungal cells was extracted using the Bligh and Dyer method with slight modifications. Three endophytic fungi that displayed the highest growth on POME were identified using ITS 1 and 4 primers and found to be related to Pestalotiopsis sp., Lasiodiplodia theobromae and Rhizoctonia bataticola. Nutrient addition caused an average increase of 8 times in biomass, indicating nitrogen requirement for cell proliferation. The highest POME concentration (75%) resulted in lower biomass yield. Furthermore, all fungal samples in high POME concentration and nutrient conditions showed a decrease in lipids accumulated per milligram of biomass whereby lipid synthesis was enhanced under nitrogen limitation (25% without nutrients). Conclusion, significance and impact of study: In conclusion, all fungal samples can be classified as oleaginous microorganisms with Pestalotipsis sp. being the most efficient (up to 70% of its biomass). This is to our knowledge the first study that shows the potential use of Pestalotiopsis sp., L. theobromae and R. bataticola for the utilisation of POME as biofuel feedstock and could in the future potentially provide an alternative approach to the treatment of POME with value-added effect.

Energy balance of biodiesel production from canola / Balanço energético da cultura de canola visando à produção de biodiesel

ABSTRACT: The aim of the present study was to estimate the energy balance (output/input ratio) of the canola crop for biodiesel production, under Brazilian conditions. Fossil energy expended in the production of 600kg of oil per hectare was 7,146,537kcal. The estimated energy yield per hectare was 9,930,000kcal from the production of 1,500kg ha-1 of seeds (40% oil and 60% oil cake), which resulted in an energy balance of 1.39. Results indicated the viability of biofuel production from canola, but also showed the need to improve the technology used to increase the energy and economic balance ratios.

RESUMO: O objetivo do trabalho foi estimar o balanço energético (razão output/input) da cultura da canola, nas condições brasileiras, para a produção de biodiesel. A energia fóssil dispendida na produção de 600kg de óleo por hectare foi de 7.146.537kcal. O rendimento energético estimado por hectare foi de 9.930.000kcal, a partir da produtividade de 1.500kg ha-1 de grãos (40% de óleo e 60% de torta), resultando no valor do balanço energético de 1,39. Os resultados indicam a viabilidade da produção do biocombustível com base na respectiva cultura, mas demonstram também a necessidade de aperfeiçoamento das tecnologias empregadas para que se aumentem os índices dos balanços energético e econômico.

Performance of an agricultural engine using blends of diesel and ethanol / Desempenho de um motor agrícola utilizando misturas de óleo diesel e etanol

ABSTRACT: This research evaluated the performance of a diesel engine in an agricultural tractor, using Diesel S500 (B5) and mixture with 3% (ED3), 6% (ED6), 9% (ED9), 12% (ED12) and 15% (ED15) of hydrous ethanol. Variables evaluated were the power, torque, specific fuel consumption, torque reserve, speed reserve and elasticity index of engine. Results indicated that using B5 and ED3 the values of torque and engine power not differ, in addition, with the ED3 the fuel consumption was lower than 5.92%. Using ED12, power has reduced in 2.97%, compared with B5, while their fuel consumption had no difference. With ED15, the power was lower 6.30% and the fuel consumption increase 3.77%, both compared with B5. Torque reserve value was increased with increasing the ethanol content in B5, reducing the speed reserve and elasticity index of engine. Ethanol in Diesel S500 (B5) can be used as an alternative fuel in agricultural tractor engines without presenting high changes in the performance, since the ethanol content is at low percentages, up to 12%.

RESUMO: Neste trabalho, foi avaliado o desempenho de um motor ciclo Diesel de um trator agrícola, utilizando óleo Diesel S500 (B5) e sua mistura com 3% (ED3), 6% (ED6), 9% (ED9), 12% (ED12) e 15% (ED15) de etanol hidratado. As variáveis estudadas foram: potência, torque, consumo específico de combustível, reserva de torque, reserva de rotação e índice de elasticidade do motor. Os resultados indicam que, utilizando B5 e ED3, os valores de torque e potência do motor não diferiram, além disso, com o ED3, o consumo de combustível foi 5,92% menor. Utilizando ED12, a potência, em relação ao B5, teve uma redução de 2,97%, sem diferença para o consumo de combustível. Já com o ED15, a potência diminuiu 6,30% e o consumo aumentou 3,77%, em comparação com o B5. Os valores de reserva de torque foram incrementados conforme aumentou o conteúdo de etanol, reduzindo a reserva de rotação e o índice de elasticidade do motor. A mistura de etanol no óleo Diesel B5 pode ser utilizada como combustível alternativo em motores agrícolas, sem apresentar alterações significativas no seu desempenho, desde que seja utilizado até 12% de etanol.