Sweet sorghum: broth clarification with enzymatic treatment increases the quality of the fermentation wort for ethanol production

Sweet sorghum is currently being evaluated throughout the world as a raw material for biofuel production because its stem juices are rich in sugars that can be directly fermented to ethanol. In this work, the fermentative efficiency of three sweet sorghum genotypes was evaluated, aiming at ethanol production, harvested in two seasons, clean and whole stems, and the treatment of the juice and broth with amylolytic enzymes in order to use the present starch to increase the production of ethanol. The experiment was carried out in the 2013/2014 harvest, in the municipality of Jaboticabal, São Paulo, Brasil, located at 21°14'05''S and 48°17'09''W. The experimental design was completely randomized, with sub-subdivided plots and four replications. The primary treatments were the sweet sorghum genotypes (CV147, CV198, and BRS508), the secondary treatments, the type of harvest (whole stems and clean stems); the tertiary the two sampling times (102 and 116 days after sowing - d.a.s) and the quaternary the application of enzymes. In the fermentation process, the yeast PE-2 was used, at the end, the wine was recovered and characterized. Fermentation efficiency and liters of ethanol per ton of sorghum were calculated. The clarification of the juice with enzymatic treatment increases the quality of the fermentation broth and makes it possible to obtain wines with lower levels of RRTs and Brix. Fermentation efficiency is not affected by the genotype; however, it is influenced by the time of harvest and the technological quality of the juice. The use of amylolytic enzymes makes it possible to obtain wines with lower levels of RRTS and Brix. The best period of industrialization was at 102 d.a.s., and the processing of whole stalks resulted in less ethanol production.

Advances in Microalgal Research in Brazil

Abstract Microalgae research has attracted interest worldwide and in order to advance algal biotechnology in Brazil, government has been funding several projects. In the last 10 years, two main funds were provided by the National Council of Scientific and Technological Development (CNPq) agency to researchers in Brazil, who study the potential uses of microalgae for biomass, bioproducts and biofuels production. These funded projects addressed aspects of algal strain identification, development of algal cultivation techniques, designing photobioreactors and raceway ponds, modeling harvesting and dewatering process, maximizing biomass and oil productivities, characterizing chemical composition with different extractions systems and determining physiochemical properties of biodiesel. This review presents the state of art of algal research conducted by Brazilian institutions. Special attention is given to the recent progress on microalgal cultivation, high-value products extracted from microalgae and potential biofuels production. This review may serve as a policy instrument for planning next steps for algal research in Brazil as well as for attracting attention from international researchers who work with microalgae and would like to pursue a future partnership on algal research with Brazilian research institutions.

Microbial green manufacturing of higher alcohols / 生物工程学报

Higher alcohols that contain more than two carbon atoms have better fuel properties than ethanol, making them important supplements and alternatives to fossil fuels. Using microbes to produce higher alcohols from renewable biomass can alleviate the current energy and environmental crises, and has become a major future direction for green biomanufacturing. Since natural microbes can only produce a few higher alcohols in small amounts, it is necessary to reconstruct the synthetic pathways for higher alcohols in model industrial strains through metabolic engineering and synthetic biology to overcome the metabolic bottlenecks. A series of milestones have been accomplished in past decades. The authors of this review have witnessed the entire journey of this field from its first success to the leaping development. On the 30th anniversary of the founding of the discipline of metabolic engineering, this review dates back to the great milestones in achieving heterologous production of higher alcohols in non-native strains. The design and optimization of high alcohol biosynthetic pathways, the expansion of feedstock, the engineering of host strains and the industrialization process are summarized. This review aims to draw further attention to microbial synthesis of higher alcohols, inspire the development of novel techniques and strategies of metabolic engineering, and promote the innovation and upgrade of China's biofuel industry.

Effective diffusion coefficients and bioconversion rates of inhibitory compounds in flocs of Saccharomyces cerevisiae

Background: Fermentation strategies for bioethanol production that use flocculating Saccharomyces cerevisiae yeast need to account for the mechanism by which inhibitory compounds, generated in the hydrolysis of lignocellulosic materials, are tolerated and detoxified by a yeast floc. Results: Diffusion coefficients and first-order kinetic bioconversion rate coefficients were measured for three fermentation inhibitory compounds (furfural, hydroxymethylfurfural, and vanillin) in self-aggregated flocs of S. cerevisiae NRRL Y-265. Thièle-type moduli and internal effectiveness factors were obtained by simulating a simple steady-state spherical floc model. Conclusions: The obtained values for the Thiéle moduli and internal effectiveness factors showed that the bioconversion rate of the inhibitory compounds is the dominant phenomenon over mass transfer inside the flocs.

Acetone­butanol­ethanol fermentation from sugarcane bagasse hydrolysates: utilization of C5 and C6 sugars

Background: Fuels and chemicals from renewable feedstocks have a growing demand, and acetone, butanol and ethanol (ABE) are some relevant examples. These molecules can be produced by the bacterial fermentation process using hydrolysates generated from lignocellulosic biomass as sugarcane bagasse, one of the most abundant sources of lignocellulosic biomass in Brazil. It originates as a residue in mills and distilleries in the production of sugar and ethanol. Results: In the present work, two strategies to generate hydrolysates of sugarcane bagasse were adopted. The fermentation of the first hydrolysate by Clostridium acetobutylicum DSM 6228 resulted in final concentrations of butanol, acetone and ethanol of 6.4, 4.5 and 0.6 g/L, respectively. On the other hand, the second hydrolysate presented better results (averages of 9.1, 5.5 and 0.8 g/L, respectively), even without the need for nutrient supplementation, since key elements were already present in the medium. The productivity (QP) and yield (YP/S) of the solvents with second hydrolysate were 0.5 g/L•h-1 and 0.4 g/g, respectively. Conclusions: The results described herein open new perspectives for the production of important molecules from residual lignocellulosic biomass for the fuel and chemical industries within the context of second-generation biorefinery.

Assessment of wasteland derived biomass for bioethanol production

Background: The bioethanol produced from biomass is a promising alternative fuel. The lignocellulose from marginal areas or wasteland could be a promising raw material for bioethanol production because it is present in large quantities, is cheap, renewable and has favorable environmental properties. Despite these advantages, lignocellulosic biomass is much more difficult to process than cereal grains, due to the need for intensive pretreatment and relatively large amounts of cellulases for efficient hydrolysis. Therefore, there is a need to develop an efficient and cost-effective method for the degradation and fermentation of lignocellulosic biomass to ethanol. Results: The usefulness of lignocellulosic biomass from wasteland for the production of bioethanol using pretreatment with the aid of ionic liquids of 1-ethyl-3-methylimidazolium acetate and 1-ethyl-3-methylimidazolium chloride was evaluated in this study. The pretreatment process, enzymatic hydrolysis and alcoholic fermentation lasted a total of 10 d. The largest amounts of bioethanol were obtained from biomass originating from agricultural wasteland, in which the dominant plant was fireweed (Chamaenerion angustifolium) and from the field where the common broom (Cytisus scoparius) was the dominant. Conclusions: The plants such as fireweed, common broom, hay and goldenrod may be useful for the production of liquid biofuels and it would be necessary in the further stage of research to establish and optimize the conditions for the technology of ethyl alcohol producing from these plant species. Enzymatic hydrolysis of biomass from agricultural wastelands results in a large increase in fermentable sugars, comparable to the enzymatic hydrolysis of rye, wheat, rice or maize straw.

Improvement of ethanol production from birch and spruce pretreated with 1-H-3-methylmorpholinium chloride

Background: Pretreatment is the critically important step for the production of ethanol from lignocelluloses. In this study, hardwood birch (Betula pendula) and softwood spruce (Norway spruce) woods were pretreated with a newly synthesized morpholinium ionic liquid, 1-H-3-methylmorpholinium chloride ([HMMorph][Cl]), followed by enzymatic hydrolysis and fermentation to ethanol. Results: [HMMorph][Cl] was synthesized using inexpensive raw materials, i.e., hydrochloric acid and N-methyl morpholine, following a simple process. The influence of pretreatment time (2, 3, 5, and 8 h) and temperature (120 and 140°C) in terms of hydrolysis efficiency was investigated. Glucose yields from enzymatic hydrolysis were improved from 13.7% to 45.7% and 12.9% to 51.8% after pretreatment of birch and spruce woods, respectively, under optimum pretreatment conditions (i.e., at 140°C for 3 h) as compared to those from pristine woods. Moreover, the yields of ethanol production from birch and spruce were increased to 34.8% and 44.2%, respectively, while the yields were negligible for untreated woods. Conclusions: This study demonstrated the ability of [HMMorph][Cl] as an inexpensive agent to pretreat both softwood and hardwood.

Aplicaciones biotecnológicas de los microorganismos / Biotechnological applications of microorganisms

Resumen La biodiversidad de los microorganismos así como la naturaleza única y las capacidades biosintéticas en condiciones ambientales específicas hacen que los microorganismos sean los probables candidatos para resolver problemas de escases de alimentos, contro de plagas, biodegradación de los xenobióticos, descomposición de la basura, las pilas de desechos producidas, entre otros. Los microorganismos ofrecen un gran potencial para la exploración de moléculas y procesos, y el conocimiento de las especies no convencionales, especialmente dentro del grupo Archaea, ha estimulado la investigación molecular de genes de interés. Estos nuevos genes pueden incorporarse mediante tecnología recombinante en especies biológicamente conocidas, como E. coli y S. cerevisiae, para la síntesis a gran escala de productos. La microbiología tecnológica tiene grandes potenciales para explorar y obstáculos por superar. Por lo tanto, solo la investigación en esta área resulta prometedora para científicos en todo el mundo. En la presente revisión se presentan las aplicaciones más significativas de los microorganismos en la industria de alimentos, la agricultura, compuestos químicos, combustibles, farmacología y materiales.

Abstract The biodiversity of microorganisms as well as the unique nature and biosynthetic capabilities in specific environmental conditions make microorganisms the likely candidates to solve problems of food shortages, pest control, biodegradation of xenobiotics, decomposition of garbage, batteries of produced waste, among others. Microorganisms offer great potential for the exploration of molecules and processes, and knowledge of non-conventional species, especially within the Archaea group, has stimulated the molecular investigation of genes of interest. These new genes can be incorporated by recombinant technology into biologically known species, such as E. coli and S. cerevisiae, for the large-scale synthesis of products. Technological microbiology has great potentials to explore and obstacles to overcome. Therefore, only research in this area is promising for scientists around the world. In this review we present the most significant applications of microorganisms in the food industry, agriculture, chemical compounds, fuels, pharmacology and materials.

Insights into the microbial community structure of anaerobic digestion of municipal solid waste landfill leachate for methane production by adaptive thermophilic granular sludge

BACKGROUND: The amount of municipal solid waste (MSW) gradually increased along with the rapid development of modern cities. A large amount of landfill leachate are generated with excessive chemical oxygen demand (COD), which create a great deal of pressure on the environment-friendly treatment process. Anaerobic digestion is an ideal technique to solve the above problem. RESULTS: A thermophilic granular sludge was successfully adapted for anaerobic digestion of MSW leachate (from an aging large-scale landfill) for methane production. The COD degradation efficiency improved by 81.8%, while the methane production rate reached 117.3 mL CH4/(g VS d), which was 2.34-fold more than the control condition. The bacterial and archaeal communities involved in the process were revealed by 16S rRNA gene high-throughput pyrosequencing. The richness of the bacterial community decreased in the process of thermophilic granular sludge, while the archaeal community structure presented a reverse phenomenon. The bacterial genus, Methanosaeta was the most abundant during the mesophilic process, while Methanobacterium, Methanoculleus, Methanosaeta and Methanosarcina were more evenly distributed. The more balanced community distribution between hydrogenotrophic and acetotrophic methanogens implied a closer interaction between the microbes, which further contributed to higher methane productivity. The detailed relationship between the key functional communities and anaerobic digestion performances were demonstrated via the multivariate canonical correspondence analysis. Conclusions: With the assistance of adaptive thermophilic granular sludge, microbial community structure was more evenly distributed, while both of COD degradation rate and methane production was improved during anaerobic digestion of MSW landfill leachate.

Redução da emissão de material particulado em função da inserção de misturas do biodiesel de soja e mamona ao diesel / Reduction emission of particulate matter as a function of insertion of biodiesel mixtures from soybean and castor bean in diesel

RESUMO Preocupações ambientais e econômicas resultantes da demanda por combustíveis fósseis corroboram a necessidade de alternativas para redução dos impactos ambientais e econômicos advindos da crescente utilização de veículos e máquinas movidas a diesel. A diversificação das matérias-primas para produção do biodiesel pode possibilitar a melhoria da qualidade do combustível e das emissões resultantes de sua utilização nos motores. Neste estudo, foi avaliada a emissão de material particulado (MP) utilizando biodiesel de soja e de mamona em misturas diesel/biodiesel, bem como sua viscosidade e estabilidade à oxidação (pré-requisitos de qualidade). Para isso, testaram-se diferentes proporções de biodiesel de soja e de mamona (SyMx), em que y e x representam os percentuais de biodiesel de soja e de mamona, respectivamente: S100M0, S75M25, S50M50, S25M75 e S0M100, em mistura ao diesel (BX), nos seguintes percentuais: 7 (diesel B7), 25 (B25), 40 (B40), 50 (B50), 75 (B75) e 100% (B100). A opacidade da fumaça, a viscosidade e a estabilidade à oxidação foram determinadas conforme as normas NBR 13037, NBR 10441 e EN 14112, respectivamente. Entre as misturas analisadas, o diesel comercial (B7) emitiu maior quantidade de MP, ao passo que as demais misturas, que atenderam aos pré-requisitos de qualidade (B25 e B40), emitiram menos MP, conforme aumento do percentual de biodiesel de mamona nas misturas SyMx, bem como com o aumento de biodiesel na mistura BX. Também foram obtidos ganhos relativos à qualidade em função das diferentes composições SyMx.

ABSTRACT Environmental and economic concerns resulting from demand for fossil fuels corroborate the need for alternatives to reduce environmental and economic impacts arising from the increasing use of diesel-powered vehicles and machines. The diversification of raw materials used to produce biodiesel can allow the improvement of fuel quality and of emissions resulting from their use in engines. This study evaluated the emission of particulate matter (PM) using biodiesel from soybean and castor bean in diesel/biodiesel mixtures, as well as its viscosity and oxidation stability (prerequisites for quality). For this purpose, biodiesel with different proportions of soybean and castor bean (SyMx) were evaluated, where y and x represent soybean and castor bean biodiesel percentages, respectively: S100M0, S75M25, S50M50, S25M75 and S0M100, mixed with diesel (BX), in the following percentages: 7 (diesel B7), 25 (B25), 40 (B40), 50 (B50), 75 (B75) and 100% (B100). The smoke opacity, viscosity and oxidation stability were determined according to NBR 13037, NBR 10441 and EN 14112, respectively. Among the analyzed mixtures, the commercial diesel (B7) emitted higher amounts of PM, whereas other mixtures, which met the prerequisites for quality (B25 and B40), emitted smaller amounts of PM as increased castor bean biodiesel percentage in mixtures SyMx, as well as with the increase of biodiesel in the mixtures BX. They were also achieved gains in quality as a function of the different compositions SyMx.

Concentrado proteico de arroz na alimentação do jundiá (Rhamdia quelen) / Rice protein concentrate in the feeding of silver catfish (Rhamdia quelen)

O objetivo do presente trabalho foi avaliar a inclusão do concentrado proteico da destilação de etanol obtido de arroz (CPA) na alimentação do jundiá. Trezentos e setenta e cinco peixes foram distribuídos em sistema de recirculação de água com 15 caixas (125L). Foram testadas três dietas (37% PB e 3200kcal/kg de energia digestível), sendo uma controle e duas testando a substituição da proteína da farinha de peixe em 25% (CPA-25%) ou 50% (CPA-50%) pelo CPA. Aos 30 dias, foram avaliadas as variáveis de desempenho, composição corporal e índices somáticos. Os animais submetidos ao tratamento CPA-25% apresentaram resposta de crescimento equivalente aos que receberam o tratamento controle, mas superior aos peixes submetidos ao CPA-50%. Não foram observadas diferenças significativas entre os tratamentos para os índices somáticos avaliados. Os animais submetidos às dietas contendo CPA apresentaram maior teor de gordura corporal. Já a deposição de gordura corporal foi superior para os peixes alimentados com CPA-25%, e a deposição de proteína corporal menor para os alimentados com CPA-50%. Os resultados indicam que o CPA pode substituir em até 25% a proteína da farinha de peixe, sem comprometer o crescimento dos jundiás, tendo esse nível de substituição proporcionado, inclusive, uma redução de 8% no custo da dieta.(AU)

The objective of this work was to evaluate the inclusion of protein concentrate from the distillation of ethanol from rice (CPA) in jundia feed. A total of 375 fish were distributed in water recirculation system with 15 boxes (125L). Three diets (37% PB and 3200kcal / kg digestible energy), one control and two were to test for the replacement of fishmeal protein by 25 (CPA-25%) and 50% (CPA-50%) by CPA. At 30 days, the variables of performance, body composition and somatic indexes were evaluated. The animals submitted to the CPA-25% treatment presented a growth response equivalent to those that received the Control treatment, but superior to the fish submitted to the CPA-50%. There were no significant differences between treatments for the somatic indices evaluated. Animals submitted to diets containing CPA had higher body fat content. Body fat deposition was higher for fish fed with CPA-25% and lower body protein deposition for those fed with CPA-50%. The results indicate that CPA can substitute up to 25% fish meal protein, without compromising the growth of jundias, and this level of substitution provided an 8% reduction in diet cost.(AU)

Evaluation of CO2 Biofixation and Biodiesel Production by Spirulina (Arthospira) Cultivated In Air-Lift Photobioreactor

ABSTRACT Spirulina is a microalgal genre that has the capacity to produce various bioproducts with applications in several areas including the energy sector. The study aimed to assess the ability of CO2 biofixation, biodiesel and other biocompounds production by Spirulina sp LEB 18 cultured in air-lift photobioreactor. The microalgae presented a rich macronutrient composition: protein (47.3%), carbohydrates (13.4%) and a high lipid content (32.7%) in a media with nitrogen reduction, CO2 using air-lift photobiorector. Furthermore, 160 mg.L.d-1 of CO2 was biofixed, generating a maximum biomass yield of 0.02 g.L.d-1. The lipids evaluated for biodiesel production presented a theoretical yield of 19.8% for in situ transesterification and 47.9% for conventional transesterification. The microalgal biomass has potential for producing biodiesel that can be applied instead or in mixture with traditional diesel fuel. The study of obtaining energy associated with the production of other high value-added biocompounds from the microalgal biomass is of high importance because in this way, the viability of biofuel production by this microorganism can be increased.

Silvopastoral System Economical and Financial feasibility with Jatropha curcas L. in Manabí, Ecuador / Viabilidad económica y financiera de sistemas silvopastoriles con Jatropha curcas L. en Manabí, Ecuador

ABSTRACT Objective. To assess the economic and financial feasibility of traditional silvopastoral systems for the biofuels production as a contribution to the sustainability of "Piñón for Galapagos" project. Materials and methods. A survey was conducted to 450 small livestock producer in 10 cantons of the Manabí province in order to collect basic agronomic knowledge, management, establishment and costs involved in production of the Piñón ((Jatropha curcas L.)/Savoy (Megathyrsus maximus) silvopastoral systems. For Piñón CP041 production recording plantation in live fence were stablished and for the tradition Piñón, the production of 10 sites were recorded, both systems since 2009. With those data were calculated the following economic indicators: ratio benefit/cost, net present value (NPV), internal rate ratio (IRR) and land expectation value (LEV). Results. The study exhibited a production decrease of Piñón with the passage of time. The CP041 INIAP improved silvopastoral system Piñón showed a B/C 1.07, NPV of USD$ 404.11, LEV US$ 970.23 and IRR of 18%. Followed by silvopastoral system with a local Piñón with a B/C 1.06, NPV of USD$ 363.66, LEV USD$ 873.10 and IRR of 17% and finally silvopastoral system without harvesting Piñón with a B/C 1.05, NPV of USD$ 285.72, LEV USD$ 685.99 and IRR of 15%. Conclusions. The alternative biofuels production was the silvopastoral systems (INIAP CP041)/Savoya in Manabí and is economically feasible. This system does not compete for arable land for food production and would not affect food security.

RESUMEN Objetivo. Evaluar la viabilidad económica y financiera de los sistemas silvopastoriles tradicionales para la producción de Biocombustibles como aporte a la sostenibilidad del proyecto "Piñón para Galápagos". Materiales y Métodos. Se llevaron a cabo encuestas a 450 pequeños productores ganaderos de 10 cantones de la provincia de Manabí con la finalidad de colectar información agronómica, manejo, costos implicados en establecimiento y producción de los sistemas silvopastoriles vigentes de Piñón (Jatropha curcas L.)/Saboya (Megathyrsus maximus). Para recopilar datos de producción del Piñón establecido en cercas vivas de Piñón INIAP CP041 e igualmente se registró la producción de sistemas en 10 sitios, desde el año 2009. Con estos datos se calcularon los siguientes indicadores financieros radio beneficio/costo (B/C), valor actual neto (VAN), tasa interna de retorno (TIR) y valor de expectativa de la tierra (VET). Resultados. El estudio mostró una disminución de la producción del Piñón con el transcurso del tiempo. El sistema silvopastoril mejorado con Piñón INIAP CP041 mostró B/C 1.07, VAN de USD$ 404.11, VET USD$ 970.23 y TIR de 18%. Seguido del sistema silvopastoril con Piñón local con un B/C 1.06, VAN de USD$ 363.66, VET USD$ 873.10 y TIR de 17% y finalmente sistema silvopastoril sin cosecha del Piñón con un B/C 1.05, VAN de USD$ 285.72, VET USD$ 685.99 y TIR de 15%. Conclusiones. La alternativa de producción de biocombustibles con sistemas silvopastoriles Piñón (INIAP CP041)/Saboya en Manabí es el sistema de mayor rentabilidad y no competiría por superficies de cultivo para la producción de alimentos, sin afectar a la seguridad alimentaria.

Bioethanol production with different dosages of the commercial Acrylamide polymer compared to a Bioextract in clarifying sugarcane juice

ABSTRACT One of the most important steps is to clarify the juice, which are added synthetic polymer acrylamide base, aiming the fast settling of impurities present in the juice. However, this input is expensive and may have carcinogenic and neurotoxic actions to humans. The search for new natural flocculants that have similarity with the commercial product is of great value. A bioextract that may be promising and has coagulant action is the Moringa oleifera Lam. In this context, the objective of the research was to evaluate the consequences of the use of moringa seed extracts and various concentrations of commercial polymer, such as sedimentation aids in clarifying sugarcane juice in the ethanol production, comparing the efficiency of the bioextract moringa. In the treatment of the juice, excessive addition of flocculants can result in reduction of sugars. The bioflocculant moringa was similar in technological features and the fermentative viability compared to usual dose of commercial polymer in Brazil. The fermentation efficiency was also higher for this flocculant, followed by moringa extract. The results obtained in this research indicate potential to the moringa bioextract, particularly in countries where the doses of flocculants are higher than 5 mg.L-1.

Utilization of a waste glycerol fraction using and reusing immobilized Gluconobacter oxydans ATCC 621 cell extract

Background: Depletion of petroleum resources has enforced the search for alternative sources of renewable energy. Introduction of biofuels into the market was expected to become a solution to this disadvantageous situation. Attempts to cover fuel demand have, however, caused another severe problem­the waste glycerol generated during biodiesel production at a concentration of approximately 10% w/w. This, in turn, prompted a global search for effective methods of valorization of the waste fraction of glycerol. Results: Utilization of the waste fraction at 48 h with an initial glycerol concentration of 30 g·L-1 and proceeding with 62% efficiency enabled the production of 9 g·L-1 dihydroxyacetone at 50% substrate consumption. The re-use of the immobilized biocatalyst resulted in a similar concentration of dihydroxyacetone (8.7 g·L-1) in two-fold shorter time, with an efficiency of 85% and lower substrate consumption (35%). Conclusions: The method proposed in this work is based on the conversion of waste glycerol to dihydroxyacetone in a reaction catalyzed by immobilized Gluconobacter oxydans cell extract with glycerol dehydrogenase activity, and it could be an effective way to convert waste glycerol into a valuable product.

Uso do metanol e risco de exposição dos trabalhadores de uma usina de biodiesel / Use of methanol and workers' risk of exposure at a biodiesel plant

Contexto: O metanol é usado como matéria-prima na fabricação de biodiesel e pode causar, em especial, danos oftalmológicos e neurológicos. A exposição ocupacional acontece principalmente pela inalação de vapores. No entanto, os dados relacionados aos efeitos da exposição crônica ao metanol em humanos são limitados. Objetivos: Mostrar situações e atividades com risco de exposição ao metanol em uma planta de biodiesel e a presença de possíveis sintomas de contaminação nos trabalhadores. Métodos: Questionário, entrevistas, observação direta e análise documental possibilitaram a coleta dos dados. Resultados: O processo produtivo apresentou oito situações de exposição ao metanol. Entre os 42 sujeitos da pesquisa, 27 trabalhavam diretamente expostos e rela-taram ter dor de cabeça (71,42%), formigamento (42,00%), entre outros sintomas. As mais importantes queixas relacionadas com os efeitos neurotóxicos foram irritação (40,50%), ansiedade (35,70%) e dor de cabeça (64,30%). Funcionários das áreas administrativas também apresentavam sintomatologia idêntica à de contaminação pelo químico. Conclusões: Trabalhadores em diferentes atividades estavam expostos ao metanol, e a análise dos sintomas associados à exposição a esse solvente revelou que a maioria apresentava alguma sintomatologia compatível com a contaminação por ele.

Background: Methanol is used as raw material for biodiesel production and might cause especially visual and neurological disorders. Occupational exposure mainly occurs through vapor inhalation. However, the available data on the effects of human chronic exposure to methanol are limited. Aims: To describe situations and activities involving risk of exposure to methanol in a biodiesel plant and the possible presence of symptoms of contamination in workers. Methods: Data collection was performed by means of direct observation, interviews, document analysis and application of a questionnaire. Results: The production process included eight different situation os methanol exposure. Among the 42 participants in the study, 27 worked under conditions of direct methanol exposure and reported headache (71.42%) and tingling (42.00%) among other symptoms. The most important complaints related to the neurotoxic effects of methanol were irritation (40.50%), anxiety (35.70%) and headache (64.30%). Similarly, workers in administrative areas exhibited the same symptoms of contamination by the chemical. Conclusions: Workers performing various different activities were exposed to methanol; analysis of the symptoms associated with exposure to the solvent showed that most of them exhibited symptoms compatible with methanol contamination.

Drying and storage of corn grains for ethanol production in Brazil / Secagem e armazenamento de grãos de milho para produção de etanol no Brasil

The aim of the present research was to evaluate the effects of drying air temperature and storage conditions used in Brazil on the quality of corn grains (Zea mays L.) for ethanol production. The experiment was set up in a completely randomized design in a (3x2x2) factorial arrangement (drying air temperatures of 80, 100 and 120 ºC vs. ambient storage conditions of 23 ºC / 60% RH and cooled to 10 ºC / 40% RH vs. storage time of zero and six months). The corn grains were harvested with a water content of 18.0% (w.b.). Then, they were dried in a convection/forced-air oven at different temperatures, until water content reached 12% (w.b.). After that, the grains were stored. It was concluded that the increase in drying air temperature reduced lipid content and starch percentage, decreasing ethanol yield to 38.74 L ton-1 of grains. Storage under refrigeration at 10 °C was favorable for the maintenance of lipid levels (+2%), starch percentage (6%) and ethanol yield (33 L ton-1 of grains). Thus, considering production conditions and weather in Brazil, grains should be dried at air temperatures up to 80 °C, and storage must be performed under refrigerated air up to 10 °C for quality assurance of maize grains in the dry season and, therefore, increased ethanol production in the industry.

O objetivo do presente trabalho foi avaliar os efeitos da secagem e as condições de temperatura do ar e armazenamento utilizadas no Brasil na qualidade de grãos de milho (Zea mays L.) para a produção de etanol. O experimento foi instalado em delineamento inteiramente casualizado, em arranjo fatorial (3x2x2) (secagem a temperatura do ar de 80, 100 e 120 ºC vs. condições de ambiente de armazenamento de 23 ºC / 60% RH e resfriamento de 10 ºC / 40% RH vs. tempo de armazenamento de zero e seis meses). Os grãos de milho foram colhidos com um teor de água de 18,0% (w.b.). Em seguida, os grãos foram secos em estufa de convecção / forçada de ar a diferentes temperaturas, até que o teor de água atingiu 12% (w.b.). Em seguida, os grãos foram armazenados. Concluiu-se que o aumento da temperatura do ar de secagem reduziu os teores de lípidos e a percentagem de amido, diminuindo o rendimento de etanol a 38,74 L ton-1 de grãos. O armazenamento sob refrigeração, a 10 °C foi favorável para a manutenção dos níveis de lípidos (+2%), percentagem de amido (6%) e rendimento de etanol (33 L ton-1 de grãos). Assim, considerando as condições de produção e clima no Brasil, os grãos devem ser secos nas temperaturas do ar de até 80 °C e o armazenamento deve ser realizado sob refrigeração do ar até 10 °C para garantir a qualidade dos grãos de milho na estação seca e, portanto, um aumento da produção de etanol na indústria.

Effect of Brachionus rubens on the growth characteristics of various species of microalgae

Background: Cultivation of algae for conversion to biofuels has gained global interest. Outdoor raceway cultivation is preferred because of its lower capital and operating costs. A major disadvantage of outdoor cultivation is susceptibility of algal crops to attack by predatory rotifers. In order to quantify the impact of rotifer attack on different species of algae, we evaluated the growth of eleven microalgal species over a 21-d period after being infected by the predatory rotifer Brachionus rubens. Results: Of the eleven species, Chlorella sorokiniana was the most susceptible with rapid decline in algal growth concomitant with increase in rotifer population growth (3.82/d). In contrast, Synechococcus elongatus andScenedesmus dimorphus were both resistant to the rotifer and suppressed rotifer growth (-0.06/d). An index of algal species susceptibility to be consumed by the rotifer was generated with C. sorokiniana as the baseline (index = 1.000) indicating most susceptible among species tested. Other species' susceptibilities are indicated in parenthesis as follows: Monoraphidium spp. (0.997), Chlamydomonas globosa (0.827), Botryococcus braunii(0.740), Chlorella minutissima (0.570), Chlamydomonas augustae (0.530), Chlamydomonas yellowstonensis (0.500), Scenedesmus bijuga (0.420), and Haematococcus pluvialis (0.360). Two species, namely, S. dimorphus andS. elongatus were unique in that they exhibited an ability to suppress the growth of the rotifer as indicated by the decline in rotifer populations in their presence. Conclusions: Variations in susceptibility of algal species to rotifer predation could be a result of their individual morphology, cell walls structure, or the biochemical composition of individual species.

Progress in chemicals production by microbial consortia / 生物工程学报

Using cheap biomass resources is a hotspot of research on industrial biotechnology. It is difficult for traditional fermentations with single strain to treat so complex components and more impurities, which becomes the key problem in industrialization. In this review, some existing industrial bioprocesses involving microbial consortia were described. Comparison of 1,3-propanediol production by microbial consortia and pure cultures were then introduced and the relationship between cells in microbial consortia were summarized. Finally, the perspective was also addressed to design and apply microbial consortia in the future.

Subproduto do biodiesel na alimentação de ruminantes: o caso da glicerina / By-product of biodiesel in ruminant feeding: the case of glycerin / Subproduto de biodiesel en la alimentación de rumiantes: el caso de la glicerina

O Brasil, devido à sua expansão territorial e variação climática, apresenta uma grande diversidade de grãos oleaginosos, o que possibilita a produção de biocombustíveis. O biodiesel é obtido a partir de matérias-primas vegetais ou animais e vem ganhando destaque devido à instabilidade dos preços do petróleo e principalmente, em consequência às pressões ambientais. Durante a produção do biodiesel, há a geração de subprodutos, e dentre eles destaca-se a glicerina, que vem sendo amplamente estudada na cadeia de produção animal, mostrando-se como uma excelente fonte energética alternativa, podendo substituir ingredientes mais onerosos na produção de rações, como o milho. No entanto, seu uso deve ser feito com cautela, sendo necessário conhecer sua composição visando à correta aplicação, uma vez que a qualidade da glicerina produzida industrialmente pode ser muito variável, influenciando dessa forma os resultados a serem obtidos.

Brazil due to its territorial expansion and climate change, presents a wide variety of oilseeds, which enables the production of biofuels. Biodiesel is obtained from vegetable or animals raw materials and is gaining prominence due to the instability in oil prices and mainly due to environmental pressures. During the production of biodiesel, there is the generation of by-products, and among them there is the glycerin, which has been widely studied in animal production chain, showing up as a great alternative energy source that can replace more expensive ingredients in feed production, such as corn. However, its use should be done with caution being necessary to know its composition with a view to correct application, since the quality of industrially produced glycerin can be very variable, thus influencing the results to be obtained.

Debido a su expansión territorial y el cambio climático, Brasil presenta una amplia variedad de semillas oleaginosas, lo que permite la producción de biocombustibles. El biodiesel es obtenido a partir de materias primas vegetales o animales, por lo que está ganando importancia debido a la inestabilidad de los precios del petróleo y principalmente, a las presiones ambientales. Durante la producción de biodiesel, son generados subproductos, entre ellos la glicerina, la cual, ha sido ampliamente estudiada en la cadena de producción animal, apareciendo como una gran fuente energética alternativa, pudiendo sustituir los ingredientes más caros en la producción de raciones, como el maíz. Sin embargo, su uso debe hacerse con precaución, siendo necesario conocer su composición, con el fin de utilizarla correctamente, ya que la calidad de la glicerina producida industrialmente puede ser muy variable, influyendo así en los resultados a ser obtenidos.