Influência da linhagem da levedura e das condições de cultivo no processo de isomerização e fermentação simultâneas da xilose
Autor(a) principal: | |
---|---|
Data de Publicação: | 2013 |
Tipo de documento: | Dissertação |
Idioma: | por |
Título da fonte: | Repositório Institucional da UFSCAR |
Texto Completo: | https://repositorio.ufscar.br/handle/ufscar/4123 |
Resumo: | The conversion of the hemicellulosic fraction in ethanol is a factor that impacts on the economic viability of the second generation ethanol production process from sugar cane bagasse. Hemicellulose from bagasse is a heteropolymer constituted by pentoses and glucose, being xylose the predominant sugar (~ 21 %). Among the available technological alternatives for ethanol production from xylose, SIF process (Simultaneous Isomerization and Fermentation), consisting of xylose conversion to xylulose by glucose isomerase (GI) enzyme and xylulose fermentation by the yeast S. cerevisiae, is considered a promising alternative. The main objectives of the present work were: i) evaluate the performance of different S. cerevisiae strains towards xylulose intake and ethanol productivity; ii) assess the influence of cultivation conditions (temperature, oxygen availability and initial xylose concentration) upon ethanol and xylitol production by the selected strains; iii) define the operation conditions for the continuous SIF process, using a system of fixed bed reactors associated in series. Preliminary experiments were conducted in 50 mL flasks, containing 4 g of pellets with a load of 20 % of immobilized GI, co-immobilized with yeast (load of 10 %) in alginate gel. For the screening of yeasts showing better performance on ethanol production from xylose, two commercial baker´s yeast strains (Itaiquara® e Fleischmann®), three industrial strains (BG-1, CAT-1 e PE-2) and one lab strain (CEN.PK113-7D) were evaluated. These experiments were performed at 35 oC, using a medium composed by xylose (60 g/L), urea (5 g/L), CaCl2 (1.9g/L) and several salts, at initial pH of 5.6. Additional SIF studies were carried out with the selected yeasts Itaiquara®, BG-1 or CEN.PK113-7D under different temperature conditions (40 oC), aeration (15 mL flasks) and initial xylose concentration (130 g/L) for comparison with the results obtained at the standard conditions. For SIF cultures, samples were withdrawal and the concentrations of reducing sugars were determined by DNS method while xylose, xylulose, ethanol and by-products (xylitol, glycerol etc) concentrations were assessed by liquid chromatography. Cell viability was also measured at the beginning and end of the experiment. When comparing the different yeasts, Itaiquara® strain presented the best performance, reaching ethanol concentrations of 22.4 g/L, with a productivity of 2.1 g/Lh. The conversion of xylose was similar for all studied industrial strains as well as among the baker s yeast and lab strains. Concerning the group of additional experiments, at 40 oC, a decrease of viability and ethanol selectivity was observed for Itaiquara®, whereas productivity and selectivity for CEN.PK113-7D. was improved. For the studies conducted under semianaerobic conditions, the yeast BG-1 showed an increase in selectivity and yield. However, the reaction time increased to app. 45 hours. On the other hand, the performance of strain Itaiquara® was not altered by the lower level of oxygen tested. In the experiment with 120 g/L of xylose, more than 40 g/L of ethanol was obtained in 24 hours of cultivation. Thus, we conclude that the SIF process proposed in the present work is a viable alternative for the production of ethanol from xylose or lignocellulosic residues. For the operation of the continuous system composed by fixed bed reactors associated in series, the recommended conditions include the Itaiquara® yeast with a temperature no higher than 35 oC, keeping the total residence time around 10 hours for a feeding supply containing 60 g/L of xylose. |
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Moraes, Guilherme SilveiraZangirolami, Teresa Cristinahttp://lattes.cnpq.br/4546701843297248http://lattes.cnpq.br/90132404852818307c79c31e-abb0-4c1d-96c7-d878c7fc52852016-06-02T19:56:52Z2013-09-022016-06-02T19:56:52Z2013-03-21MORAES, Guilherme da Silveira. Influência da linhagem da levedura e das condições de cultivo no processo de isomerização e fermentação simultâneas da xilose. 2013. 102 f. Dissertação (Mestrado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2013.https://repositorio.ufscar.br/handle/ufscar/4123The conversion of the hemicellulosic fraction in ethanol is a factor that impacts on the economic viability of the second generation ethanol production process from sugar cane bagasse. Hemicellulose from bagasse is a heteropolymer constituted by pentoses and glucose, being xylose the predominant sugar (~ 21 %). Among the available technological alternatives for ethanol production from xylose, SIF process (Simultaneous Isomerization and Fermentation), consisting of xylose conversion to xylulose by glucose isomerase (GI) enzyme and xylulose fermentation by the yeast S. cerevisiae, is considered a promising alternative. The main objectives of the present work were: i) evaluate the performance of different S. cerevisiae strains towards xylulose intake and ethanol productivity; ii) assess the influence of cultivation conditions (temperature, oxygen availability and initial xylose concentration) upon ethanol and xylitol production by the selected strains; iii) define the operation conditions for the continuous SIF process, using a system of fixed bed reactors associated in series. Preliminary experiments were conducted in 50 mL flasks, containing 4 g of pellets with a load of 20 % of immobilized GI, co-immobilized with yeast (load of 10 %) in alginate gel. For the screening of yeasts showing better performance on ethanol production from xylose, two commercial baker´s yeast strains (Itaiquara® e Fleischmann®), three industrial strains (BG-1, CAT-1 e PE-2) and one lab strain (CEN.PK113-7D) were evaluated. These experiments were performed at 35 oC, using a medium composed by xylose (60 g/L), urea (5 g/L), CaCl2 (1.9g/L) and several salts, at initial pH of 5.6. Additional SIF studies were carried out with the selected yeasts Itaiquara®, BG-1 or CEN.PK113-7D under different temperature conditions (40 oC), aeration (15 mL flasks) and initial xylose concentration (130 g/L) for comparison with the results obtained at the standard conditions. For SIF cultures, samples were withdrawal and the concentrations of reducing sugars were determined by DNS method while xylose, xylulose, ethanol and by-products (xylitol, glycerol etc) concentrations were assessed by liquid chromatography. Cell viability was also measured at the beginning and end of the experiment. When comparing the different yeasts, Itaiquara® strain presented the best performance, reaching ethanol concentrations of 22.4 g/L, with a productivity of 2.1 g/Lh. The conversion of xylose was similar for all studied industrial strains as well as among the baker s yeast and lab strains. Concerning the group of additional experiments, at 40 oC, a decrease of viability and ethanol selectivity was observed for Itaiquara®, whereas productivity and selectivity for CEN.PK113-7D. was improved. For the studies conducted under semianaerobic conditions, the yeast BG-1 showed an increase in selectivity and yield. However, the reaction time increased to app. 45 hours. On the other hand, the performance of strain Itaiquara® was not altered by the lower level of oxygen tested. In the experiment with 120 g/L of xylose, more than 40 g/L of ethanol was obtained in 24 hours of cultivation. Thus, we conclude that the SIF process proposed in the present work is a viable alternative for the production of ethanol from xylose or lignocellulosic residues. For the operation of the continuous system composed by fixed bed reactors associated in series, the recommended conditions include the Itaiquara® yeast with a temperature no higher than 35 oC, keeping the total residence time around 10 hours for a feeding supply containing 60 g/L of xylose.A conversão da fração hemicelulósica da biomassa em etanol é um dos fatores que impactam a viabilidade econômica do processo de produção de etanol de segunda geração a partir do bagaço de cana-de-açúcar. A hemicelulose do bagaço é um heteropolímero constituído por pentoses e glicose, sendo a xilose o açúcar predominante (~ 21 %). Dentre as diversas alternativas tecnológicas para a produção de etanol a partir de xilose, o processo SIF (Simultânea Isomerização e Fermentação), consistindo na isomerização da xilose em xilulose pela enzima glicose-isomerase (GI) e na fermentação da xilulose pela levedura S. cerevisiae, é considerado uma alternativa promissora. Os principais objetivos do presente trabalho foram: i) avaliar o desempenho de diferentes cepas de S. cerevisiae em termos de assimilação de xilulose e produtividade em etanol; ii) estudar a influência das condições de cultivo (disponibilidade de oxigênio, temperatura e da concentração inicial de xilose) na produção de etanol e xilitol pelas cepas selecionadas; iii) definir as condições de operação para um processo SIF contínuo em sistema de reatores de leito fixo associados em série. Os experimentos preliminares foram conduzidos em frascos de 50 mL contendo 4 g de pelletes com carga de 20 % de glicose isomerase imobilizada, coimobilizada com levedura (carga de 10%) em gel de alginato. Para a seleção da levedura com melhor desempenho na produção de etanol a partir de xilose, foram avaliadas duas linhagens de levedura de panificação comercial (Itaiquara® e Fleischmann®), três cepas industriais (BG-1, CAT-1 e PE-2) e uma utilizada em laboratório (CEN.PK113-7D). Esses experimentos SIF foram conduzidos a 35ºC utilizando meio composto por xilose (60 g/L), ureia (5 g/L), CaCl2 (1,9 g/L) e sais diversos, em pH inicial 5,6. Experimentos SIF complementares foram realizados com as leveduras selecionadas Itaiquara®, BG-1 ou CEN.PK113-7D em diferentes condições de temperatura (40oC), aeração (frascos de 15 mL) e concentração inicial de xilose (130 g/L) para comparação com os resultados obtidos nas condições padrão. Em todos os experimentos SIF, amostras foram retiradas para determinação da concentração de açúcares redutores (método DNS) e de xilose, xilulose, etanol e subprodutos (xilitol, glicerol etc.) por cromatografia em fase líquida. Foi também acompanhada a viabilidade celular ao longo do cultivo. Na comparação entre as diferentes leveduras, destacou-se especialmente a levedura Itaiquara®, alcançando concentrações de etanol de 22,4 g/L, com produtividade em etanol de 2,1 g/Lh. A conversão de xilose foi semelhante entre as leveduras industriais e entre as leveduras de panificação e a de laboratório. Quanto ao conjunto de experimentos complementares, na temperatura de 40ºC houve diminuição de viabilidade e seletividade em etanol para a Itaiquara® e melhora na produtividade e seletividade para a CEN.PK113-7D. Nos experimentos realizados em condições semianaeróbias, a levedura BG-1 apresentou aumento de seletividade e rendimento em etanol, porém para um tempo de reação de 45 horas, aproximadamente. Já a levedura Itaiquara® não teve seu desempenho influenciado pela menor disponibilidade de oxigênio. No experimento realizado com 130 g/L de xilose, alcançou-se mais de 40 g/L de etanol em 24 horas de cultivo. Conclui-se, assim, que o processo SIF de xilose, proposto no presente trabalho, é uma alternativa viável para a produção de etanol a partir de xilose ou de resíduos lignocelulósicos. Para a operação em sistema contínuo composto por reatores de leito fixo associados em série recomenda-se a utilização de levedura Itaiquara® e de temperatura de, no máximo, 35ºC, mantendo-se o tempo de residência total em torno de 10 horas para uma alimentação contendo 60 g/L de xilose.Financiadora de Estudos e Projetosapplication/pdfporUniversidade Federal de São CarlosPrograma de Pós-Graduação em Engenharia Química - PPGEQUFSCarBREngenharia bioquímicaS. cerevisiaeGlicose isomeraseXiloseXiluloseEtanolLevedura de panificaçãoIsomerizaçãoFermentação simultâneasXyloseXyluloseBaker´s yeastSimultaneous isomerizationFermentationENGENHARIAS::ENGENHARIA QUIMICAInfluência da linhagem da levedura e das condições de cultivo no processo de isomerização e fermentação simultâneas da xiloseinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesis-1-14c81169f-86ab-4df0-8284-9cb6516960a4info:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFSCARinstname:Universidade Federal de São Carlos (UFSCAR)instacron:UFSCARORIGINAL5322.pdfapplication/pdf3668179https://repositorio.ufscar.br/bitstream/ufscar/4123/1/5322.pdfe3612c159bebd3f0a5be1640868316aeMD51TEXT5322.pdf.txt5322.pdf.txtExtracted texttext/plain0https://repositorio.ufscar.br/bitstream/ufscar/4123/2/5322.pdf.txtd41d8cd98f00b204e9800998ecf8427eMD52THUMBNAIL5322.pdf.jpg5322.pdf.jpgIM Thumbnailimage/jpeg7647https://repositorio.ufscar.br/bitstream/ufscar/4123/3/5322.pdf.jpg163407878d3ad94df5bee357abe5e50cMD53ufscar/41232023-09-18 18:31:47.737oai:repositorio.ufscar.br:ufscar/4123Repositório InstitucionalPUBhttps://repositorio.ufscar.br/oai/requestopendoar:43222023-09-18T18:31:47Repositório Institucional da UFSCAR - Universidade Federal de São Carlos (UFSCAR)false |
dc.title.por.fl_str_mv |
Influência da linhagem da levedura e das condições de cultivo no processo de isomerização e fermentação simultâneas da xilose |
title |
Influência da linhagem da levedura e das condições de cultivo no processo de isomerização e fermentação simultâneas da xilose |
spellingShingle |
Influência da linhagem da levedura e das condições de cultivo no processo de isomerização e fermentação simultâneas da xilose Moraes, Guilherme Silveira Engenharia bioquímica S. cerevisiae Glicose isomerase Xilose Xilulose Etanol Levedura de panificação Isomerização Fermentação simultâneas Xylose Xylulose Baker´s yeast Simultaneous isomerization Fermentation ENGENHARIAS::ENGENHARIA QUIMICA |
title_short |
Influência da linhagem da levedura e das condições de cultivo no processo de isomerização e fermentação simultâneas da xilose |
title_full |
Influência da linhagem da levedura e das condições de cultivo no processo de isomerização e fermentação simultâneas da xilose |
title_fullStr |
Influência da linhagem da levedura e das condições de cultivo no processo de isomerização e fermentação simultâneas da xilose |
title_full_unstemmed |
Influência da linhagem da levedura e das condições de cultivo no processo de isomerização e fermentação simultâneas da xilose |
title_sort |
Influência da linhagem da levedura e das condições de cultivo no processo de isomerização e fermentação simultâneas da xilose |
author |
Moraes, Guilherme Silveira |
author_facet |
Moraes, Guilherme Silveira |
author_role |
author |
dc.contributor.authorlattes.por.fl_str_mv |
http://lattes.cnpq.br/9013240485281830 |
dc.contributor.author.fl_str_mv |
Moraes, Guilherme Silveira |
dc.contributor.advisor1.fl_str_mv |
Zangirolami, Teresa Cristina |
dc.contributor.advisor1Lattes.fl_str_mv |
http://lattes.cnpq.br/4546701843297248 |
dc.contributor.authorID.fl_str_mv |
7c79c31e-abb0-4c1d-96c7-d878c7fc5285 |
contributor_str_mv |
Zangirolami, Teresa Cristina |
dc.subject.por.fl_str_mv |
Engenharia bioquímica S. cerevisiae Glicose isomerase Xilose Xilulose Etanol Levedura de panificação Isomerização Fermentação simultâneas |
topic |
Engenharia bioquímica S. cerevisiae Glicose isomerase Xilose Xilulose Etanol Levedura de panificação Isomerização Fermentação simultâneas Xylose Xylulose Baker´s yeast Simultaneous isomerization Fermentation ENGENHARIAS::ENGENHARIA QUIMICA |
dc.subject.eng.fl_str_mv |
Xylose Xylulose Baker´s yeast Simultaneous isomerization Fermentation |
dc.subject.cnpq.fl_str_mv |
ENGENHARIAS::ENGENHARIA QUIMICA |
description |
The conversion of the hemicellulosic fraction in ethanol is a factor that impacts on the economic viability of the second generation ethanol production process from sugar cane bagasse. Hemicellulose from bagasse is a heteropolymer constituted by pentoses and glucose, being xylose the predominant sugar (~ 21 %). Among the available technological alternatives for ethanol production from xylose, SIF process (Simultaneous Isomerization and Fermentation), consisting of xylose conversion to xylulose by glucose isomerase (GI) enzyme and xylulose fermentation by the yeast S. cerevisiae, is considered a promising alternative. The main objectives of the present work were: i) evaluate the performance of different S. cerevisiae strains towards xylulose intake and ethanol productivity; ii) assess the influence of cultivation conditions (temperature, oxygen availability and initial xylose concentration) upon ethanol and xylitol production by the selected strains; iii) define the operation conditions for the continuous SIF process, using a system of fixed bed reactors associated in series. Preliminary experiments were conducted in 50 mL flasks, containing 4 g of pellets with a load of 20 % of immobilized GI, co-immobilized with yeast (load of 10 %) in alginate gel. For the screening of yeasts showing better performance on ethanol production from xylose, two commercial baker´s yeast strains (Itaiquara® e Fleischmann®), three industrial strains (BG-1, CAT-1 e PE-2) and one lab strain (CEN.PK113-7D) were evaluated. These experiments were performed at 35 oC, using a medium composed by xylose (60 g/L), urea (5 g/L), CaCl2 (1.9g/L) and several salts, at initial pH of 5.6. Additional SIF studies were carried out with the selected yeasts Itaiquara®, BG-1 or CEN.PK113-7D under different temperature conditions (40 oC), aeration (15 mL flasks) and initial xylose concentration (130 g/L) for comparison with the results obtained at the standard conditions. For SIF cultures, samples were withdrawal and the concentrations of reducing sugars were determined by DNS method while xylose, xylulose, ethanol and by-products (xylitol, glycerol etc) concentrations were assessed by liquid chromatography. Cell viability was also measured at the beginning and end of the experiment. When comparing the different yeasts, Itaiquara® strain presented the best performance, reaching ethanol concentrations of 22.4 g/L, with a productivity of 2.1 g/Lh. The conversion of xylose was similar for all studied industrial strains as well as among the baker s yeast and lab strains. Concerning the group of additional experiments, at 40 oC, a decrease of viability and ethanol selectivity was observed for Itaiquara®, whereas productivity and selectivity for CEN.PK113-7D. was improved. For the studies conducted under semianaerobic conditions, the yeast BG-1 showed an increase in selectivity and yield. However, the reaction time increased to app. 45 hours. On the other hand, the performance of strain Itaiquara® was not altered by the lower level of oxygen tested. In the experiment with 120 g/L of xylose, more than 40 g/L of ethanol was obtained in 24 hours of cultivation. Thus, we conclude that the SIF process proposed in the present work is a viable alternative for the production of ethanol from xylose or lignocellulosic residues. For the operation of the continuous system composed by fixed bed reactors associated in series, the recommended conditions include the Itaiquara® yeast with a temperature no higher than 35 oC, keeping the total residence time around 10 hours for a feeding supply containing 60 g/L of xylose. |
publishDate |
2013 |
dc.date.available.fl_str_mv |
2013-09-02 2016-06-02T19:56:52Z |
dc.date.issued.fl_str_mv |
2013-03-21 |
dc.date.accessioned.fl_str_mv |
2016-06-02T19:56:52Z |
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info:eu-repo/semantics/publishedVersion |
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dc.identifier.citation.fl_str_mv |
MORAES, Guilherme da Silveira. Influência da linhagem da levedura e das condições de cultivo no processo de isomerização e fermentação simultâneas da xilose. 2013. 102 f. Dissertação (Mestrado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2013. |
dc.identifier.uri.fl_str_mv |
https://repositorio.ufscar.br/handle/ufscar/4123 |
identifier_str_mv |
MORAES, Guilherme da Silveira. Influência da linhagem da levedura e das condições de cultivo no processo de isomerização e fermentação simultâneas da xilose. 2013. 102 f. Dissertação (Mestrado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2013. |
url |
https://repositorio.ufscar.br/handle/ufscar/4123 |
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por |
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openAccess |
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Universidade Federal de São Carlos |
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Programa de Pós-Graduação em Engenharia Química - PPGEQ |
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UFSCar |
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BR |
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