Base de dados : LILACS
Pesquisa : D20.147 [Categoria DeCS]
Referências encontradas : 91 [refinar]
Mostrando: 1 .. 10   no formato [Detalhado]

página 1 de 10 ir para página                        

  1 / 91 LILACS  
              next record last record
seleciona
para imprimir
Fotocópia
Texto completo
Id: biblio-1051273
Autor: Martinez-Silveira, Adalgisa; Villarreal, Romina; Garmendia, Gabriela; Rufo, Caterina; Vero, Silvana.
Título: Process conditions for a rapid in situ transesterification for biodiesel production from oleaginous yeasts
Fonte: Electron. j. biotechnol;38:1-9, Mar. 2019. tab, graf.
Idioma: en.
Resumo: 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.
Descritores: Leveduras/metabolismo
Biocombustíveis
-Tempo de Reação
Rhodotorula
Biomassa
Meio Ambiente
Esterificação
Ésteres
Ácidos Graxos
Energia Renovável
Lipídeos
Metilação
Responsável: CL1.1 - Biblioteca Central


  2 / 91 LILACS  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
Id: biblio-1052269
Autor: Feng, Shoushuai; Hou, Shaoxiang; Huang, Xing; Fang, Zheng; Tong, Yanjun; Yang, Hailin.
Título: Insights into the microbial community structure of anaerobic digestion of municipal solid waste landfill leachate for methane production by adaptive thermophilic granular sludge
Fonte: Electron. j. biotechnol;39:98-106, may. 2019. tab, graf, ilus.
Idioma: en.
Projeto: National Natural Science Foundation of China; . Social Development Projects of Jiangsu Province; . Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education; . Key Laboratory of Industrial Biotechnology, Ministry of Education; . Priority Academic Program Development of; . Jiangsu Higher Education Institutions, and Program of Introducing; . Talents of Discipline to Universities.
Resumo: 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.
Descritores: Bactérias Anaeróbias/metabolismo
Resíduos Sólidos
Digestão Anaeróbia
Tratamento de Lodos
Metano/metabolismo
-Esgotos/microbiologia
Bactérias Anaeróbias/isolamento & purificação
Poluentes Químicos da Água
Reação em Cadeia da Polimerase
Área Urbana
Biocombustíveis
Análise da Demanda Biológica de Oxigênio
Temperatura Alta
Anaerobiose
Responsável: CL1.1 - Biblioteca Central


  3 / 91 LILACS  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo SciELO Brasil
Texto completo
Id: lil-521116
Autor: Talamini, Edson; Dewes, Homero.
Título: O governo e a mídia na configuração do macroambiente para os biocombustíveis líquidos no Brasil / Government and media in the configuration of the macroenvironment for liquid biofuels in Brazil
Fonte: Rev. adm. pública;43(2):415-444, mar.-abr. 2009. ilus, graf, tab.
Idioma: pt.
Projeto: Finep; . Fapergs. Projeto Estruturante em Agroenergia - RS.
Resumo: Este artigo identifica as dimensões nas quais o governo e a mídia do Brasil têm configurado o macroambiente para os biocombustíveis líquidos ao longo do tempo e testam a existência de similaridade entre esses meios de expressão da sociedade na configuração do macroambiente. Para atingir o objetivo, foi realizada uma pesquisa documental a partir das notícias sobre o tema "biocombustíveis líquidos" veiculadas pela mídia escrita e de documentos oficiais do governo brasileiro tratando do mesmo tema. Foram coletados documentos textuais em formato eletrônico para um período de 10 anos (1997 a 2006). A extração do conhecimento dos textos em formato eletrônico foi realizada por meio de mineração em textos, aplicando-se uma estrutura de análise específica contendo as dimensões macroambientais e suas respectivas "palavras-d", que foram definidas a partir das palavras mais frequentes nas áreas do conhecimento relacionadas a cada dimensão. Os resultados indicam que a configuração do macroambiente para os biocombustíveis líquidos pela mídia e pelo governo difere quanto ao uso das dimensões macroambientais. A configuração do macroambiente também apresentou variações ao longo do período analisado, tanto na mídia quanto no governo. Testes de similaridade, aderência e homogeneidade confirmam a existência de diferenças entre a mídia e o governo. As implicações dos resultados encontrados para a atividade de escaneamento macroambiental destinado ao planejamento estratégico das organizações em geral e dos biocombustíveis líquidos em particular são discutidas.

This article identifies the dimensions in which the Brazilian government and the media have shaped the macroenvironment for liquid biofuels through time, and tests the similarities among these means of expression of the society in the macroenvironmental setting. It conducts a documental research of the news on liquid biofuels published by the press and of official documents of the Brazilian government about the same subject. Electronic written documents covering a 10-year period (1997 to 2006) were collected and the information from them was extracted through text mining applying a specific analytical framework containing the macroenvironmental dimensions and their respective 'd-words', which were defined from the most frequent words in the knowledge areas related to each dimension. The results show that the configuration of the macroenvironment for liquid biofuels differs in the press and in the government. The setting of the macroenvironment also presented variations throughout the period. Similarity, adherence and homogeneity tests confirmed the existence of differences between the press and the government. The article discusses the implications of the results for the activity of macroenvironmental scanning related to the strategic planning of the organizations in general and of the liquid biofuels specifically.
Descritores: Planejamento Estratégico
Biocombustíveis
Mineração de Dados
Governo
Meios de Comunicação de Massa
Responsável: BR67.1 - CIR - Biblioteca - Centro de Informação e Referência


  4 / 91 LILACS  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo SciELO Brasil
Texto completo
Id: biblio-886773
Autor: CORDEIRO, RAQUEL S; VAZ, IZABELA C D; MAGALHÃES, SÉRGIA M S; BARBOSA, FRANCISCO A R.
Título: Effects of nutritional conditions on lipid production by cyanobacteria
Fonte: An. acad. bras. ciênc;89(3,supl):2021-2031, 2017. tab, graf.
Idioma: en.
Projeto: Conselho Nacional de Desenvolvimento Científico e Tecnológico; . Fundação de Amparo à Pesquisa do Estado de Minas Gerais.
Resumo: ABSTRACT The present study evaluated the effects of the culturing media and the levels of nitrogen and phosphorus on the growth, biomass productivity and lipid production of four species of Microcystis (M. novacekii, M. aeruginosa, M panniformis and M. protocystis). The lipid extract was obtained by refluxing with dichloromethane (Soxhlet). The biomass and biomass productivity yields were maximized with ASM-1 medium treatment enriched with nitrogen and/or phosphorus (0.25-0.65 g/L and 25-50.7 mg/L d-1, respectively). The lipid extract yields from M. panniformis and M. novacekii were inversely correlated with the concentration of nitrogen and directly correlated with the concentration of phosphorus (35.8 % and 31.7 %). The lipid extract yield from M. aeruginosa was inversely correlated with the nutrient concentration (23.3 %). M. protocystis exhibited a higher lipid content in the control medium (41.5 %) than in the nitrogen-enriched media. The recorded results show that a nutrient-poor culture medium favours cell growth and stimulates lipid accumulation, which directly affects the cost of cultivation by reducing nutrient consumption. All studied species may serve as biomass sources for biodiesel production, although M. protocystis exhibited the highest lipid production. Further studies are necessary to determine the composition of the recorded lipid extract.
Descritores: Biocombustíveis/microbiologia
Lipídeos/biossíntese
-Fósforo/metabolismo
Cianobactérias/química
Biomassa
Meios de Cultura/farmacologia
Nitrogênio/metabolismo
Responsável: BR1.1 - BIREME


  5 / 91 LILACS  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo SciELO Brasil
Texto completo
Id: biblio-886868
Autor: FREITA, CRISTHYANE M; FREITA, LIDYANE A; TRALLI, LETICIA F; SILVA, ALINE F; MENDES, FRANCIELE Q; TEIXEIRA, VITOR; MUTTON, MARCIA J R.
Título: Bioethanol production with different dosages of the commercial Acrylamide polymer compared to a Bioextract in clarifying sugarcane juice
Fonte: An. acad. bras. ciênc;89(4):3093-3102, Oct.-Dec. 2017. tab.
Idioma: en.
Resumo: 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.
Descritores: Polímeros/metabolismo
Extratos Vegetais/química
Acrilamida/metabolismo
Moringa oleifera/química
Saccharum/química
Biocombustíveis
Sucos de Frutas e Vegetais
-Extratos Vegetais/metabolismo
Saccharum/metabolismo
Etanol
Fermentação
Tipo de Publ: Estudo Comparativo
Responsável: BR1.1 - BIREME


  6 / 91 LILACS  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
Id: biblio-1087252
Autor: Mohammadi, Marzieh; Shafiei, Marzieh; Karimi, Keikhosro; Abdolmaleki, Amir; Mikkola, Jyri-Pekka; Abdolmaleki, Amir.
Título: Improvement of ethanol production from birch and spruce pretreated with 1-H-3-methylmorpholinium chloride
Fonte: Electron. j. biotechnol;41:95-99, sept. 2019. graf, tab, ilus.
Idioma: en.
Resumo: 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.
Descritores: Betula/metabolismo
Etanol/metabolismo
Etanol/síntese química
Lignina/metabolismo
-Celulose/metabolismo
Tratamento Preliminar
Cloretos/química
Abies
Biocombustíveis
Fermentação
Hidrólise
Responsável: CL1.1 - Biblioteca Central


  7 / 91 LILACS  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
Id: biblio-1053560
Autor: Rolz, Carlos; León, Roberto de; Mendizábal de Montenegro, Ana Luisa.
Título: Co-production of ethanol and biodiesel from sweet sorghum juice in two consecutive fermentation steps
Fonte: Electron. j. biotechnol;41:13-21, sept. 2019. ilus, graf, tab.
Idioma: en.
Resumo: Background: Sugars from sweet sorghum stalks can be used to produce ethanol and also to grow oleaginous yeasts. Instead of two separate processes, in this paper we propose a different route producing ethanol and microbial oil in two consecutive fermentation steps. Results: Three yeasts were compared in the first ethanol producing step. In the second step four different oleaginous yeasts were tested. Sweet sorghum juice was first clarified and concentrated. High gravity ethanol fermentation was carried out with concentrated juice with 23.7 g/100 mL of total sugars and without added nutrients. Total sugars were 2.5 times more than the original clarified juice. One yeast gave the best overall response over the two other tested; relative high ethanol productivity, 1.44 g ethanol/L•h−1 , and 90% of sugar consumption. Aeration by flask agitation produced superior results than static flasks for all yeasts. Microbial oil production was done employing the residual liquid left after ethanol separation. The pooled residual liquid from the ethanol distillation contained 7.08 g/mL of total carbohydrates, rich in reducing sugars. Trichosporon oleaginosus and Lipomyces starkeyi produced higher dry biomass, total sugar consumption and oil productivity than the other two oleaginous yeasts tested; with values around 25 g/L, 80%, and 0.55 g oil/L•h−1 respectively. However, the biomass oil content in all yeasts was relatively low in the range of 14 to 16%. Conclusion: The two step process is viable and could be considered an integral part of a consolidated biorefinery from sweet sorghum.
Descritores: Sorghum/química
Etanol/metabolismo
Sucos de Frutas e Vegetais
-Saccharomyces cerevisiae
Leveduras
Trichosporon
Açúcares
Sucos
Lipomyces
Biocombustíveis/microbiologia
Fermentação
Responsável: CL1.1 - Biblioteca Central


  8 / 91 LILACS  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
Id: biblio-1053552
Autor: Smuga-Kogut, Malgorzata; Piskier, Tomasz; Walendzik, Bartosz; Szymanowska-Powalowska, Daria.
Título: Assessment of wasteland derived biomass for bioethanol production
Fonte: Electron. j. biotechnol;41:1-8, sept. 2019. tab, ilus, graf.
Idioma: en.
Projeto: National Science Centre as part of MINIATURA 1.
Resumo: 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.
Descritores: Solo/química
Biomassa
Etanol/metabolismo
-Biodegradação Ambiental
Celulases/análise
Enzimas/metabolismo
Líquidos Iônicos
Biocombustíveis
Hidrólise
Lignina/análise
Responsável: CL1.1 - Biblioteca Central


  9 / 91 LILACS  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
Id: biblio-1087350
Autor: Conceição Gomes, Absai da; Rodrigues, Maria Isabel; França Passos, Douglas de; Machado de Castro, Aline; Mello Santa Anna, Lidia Maria; Pereira Jr, Nei.
Título: Acetone­butanol­ethanol fermentation from sugarcane bagasse hydrolysates: utilization of C5 and C6 sugars
Fonte: Electron. j. biotechnol;42:16-22, Nov. 2019. graf, tab.
Idioma: en.
Resumo: 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.
Descritores: Acetona/metabolismo
Celulose/metabolismo
Saccharum/metabolismo
Etanol/metabolismo
Butanóis/metabolismo
-Brasil
Celulose/química
Saccharum/química
Clostridium acetobutylicum/metabolismo
Biocombustíveis
Fermentação
Responsável: CL1.1 - Biblioteca Central


  10 / 91 LILACS  
              first record previous record
seleciona
para imprimir
Fotocópia
Texto completo
Id: biblio-1087340
Autor: Landaeta, Roberto; Acevedo, Fernando; Aroca, Germán.
Título: Effective diffusion coefficients and bioconversion rates of inhibitory compounds in flocs of Saccharomyces cerevisiae
Fonte: Electron. j. biotechnol;42:1-5, Nov. 2019. tab, graf.
Idioma: en.
Resumo: 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.
Descritores: Saccharomyces cerevisiae/metabolismo
Biocombustíveis
-Leveduras
Benzaldeídos
Biodegradação Ambiental
Inativação Metabólica
Difusão
Floculação
Furaldeído/análogos & derivados
Responsável: CL1.1 - Biblioteca Central



página 1 de 10 ir para página                        
   


Refinar a pesquisa
  Base de dados : Formulário avançado   

    Pesquisar no campo  
1  
2
3
 
           



Search engine: iAH v2.6 powered by WWWISIS

BIREME/OPAS/OMS - Centro Latino-Americano e do Caribe de Informação em Ciências da Saúde