Avaliação da influência de surfactantes químico e biológico na hidrólise enzimática de casca de coco verde após pré-tratamento ácido/alcalino e com peróxido de hidrogênio alcalino
In Brazil many types of bioproducts and agroindustrial waste are generated currently, such as cacashew apple bagasse and coconut husk, for example. The final disposal of these wastes causes serious environmental issues. In this sense, waste lignocellulosic content, as the shell of the coconut is a r...
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Ramnolipídeos Triton X-100 Celulose Casca de coco verde Pré-tratamento CNPQ::ENGENHARIAS::ENGENHARIA QUIMICA |
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Ramnolipídeos Triton X-100 Celulose Casca de coco verde Pré-tratamento CNPQ::ENGENHARIAS::ENGENHARIA QUIMICA Araújo, Cynthia Kérzia Costa de Avaliação da influência de surfactantes químico e biológico na hidrólise enzimática de casca de coco verde após pré-tratamento ácido/alcalino e com peróxido de hidrogênio alcalino |
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In Brazil many types of bioproducts and agroindustrial waste are generated currently, such as cacashew apple bagasse and coconut husk, for example. The final disposal of these wastes causes serious environmental issues. In this sense, waste lignocellulosic content, as the shell of the coconut is a renewable and abundant raw material in which its use has an increased interest mainly for the 2nd generation ethanol production. The hydrolysis of cellulose to reducing sugars such as glucose and xylose is catalysed by a group of enzymes called cellulases. However, the main bottleneck in the enzymatic hydrolysis of cellulose is the significant deactivation of the enzyme that shows irreversible adsorption mechanism leading to reduction of the cellulose adsorption onto cellulose. Studies have shown that the use of surfactants can modify the surface property of the cellulose therefore minimizing the irreversible binding. The main objective of the present study was to evaluate the influence of chemical and biological surfactants during the hydrolysis of coconut husk which was subjected to two pre-treatment in order to improve the accessibility of the enzymes to the cellulose, removing this way, part of the lignin and hemicellulose present in the structure of the material. The pre-treatments applied to coconut bagasse were: Acid/Alkaline using 0.6M H2SO4 followed by 1M NaOH, and the one with Alkaline Hydrogen Peroxide at a concentration of 7.35% (v/v) and pH 11.5. Both the material no treatment and pretreated were characterized using analysis of diffraction X-ray (XRD), Scanning Electron Microscopy (SEM) and methods established by NREL. The influence of both surfactants, chemical and biological, was used at concentrations below the critical micelle concentration (CMC), and the concentrations equal to the CMC. The application of pre-treatment with coconut residue was efficient for the conversion to glucose, as well as for the production of total reducing sugars, it was possible to observe that the pretreatment fragmented the structure as well as disordered the fibers. Regarding XRD analysis, a significant increase in crystallinity index was observed for pretreated bagasse acid/alkali (51.1%) compared to the no treatment (31.7%), while that for that treated with PHA, the crystallinity index was slightly lower, around 29%. In terms of total reducing sugars it was not possible to observe a significant difference between the hydrolysis carried out without the use of surfactant compared to the addition of Triton and rhamnolipid. However, by observing the conversions achieved during the hydrolysis, it was noted that the best conversion was using the rhamnolipíd for the husk pretreated with acid/alkali, reaching a value of 33%, whereas using Triton the higher conversion was 23.8%. The coconut husk is a residue which can present a high potential to the 2nd generation ethanol production, being the rhamonolipid a very efficient biosurfactant for use as an adjuvant in the enzymatic process in order to act on the material structure reducing its recalcitrance and therefore improving the conditions of access for enzymes to the substrate increasing thus the conversion of cellulose to glucose. |
| author2 |
Santos, Everaldo Silvino dos |
| author_facet |
Santos, Everaldo Silvino dos Araújo, Cynthia Kérzia Costa de |
| format |
masterThesis |
| author |
Araújo, Cynthia Kérzia Costa de |
| author_sort |
Araújo, Cynthia Kérzia Costa de |
| title |
Avaliação da influência de surfactantes químico e biológico na hidrólise enzimática de casca de coco verde após pré-tratamento ácido/alcalino e com peróxido de hidrogênio alcalino |
| title_short |
Avaliação da influência de surfactantes químico e biológico na hidrólise enzimática de casca de coco verde após pré-tratamento ácido/alcalino e com peróxido de hidrogênio alcalino |
| title_full |
Avaliação da influência de surfactantes químico e biológico na hidrólise enzimática de casca de coco verde após pré-tratamento ácido/alcalino e com peróxido de hidrogênio alcalino |
| title_fullStr |
Avaliação da influência de surfactantes químico e biológico na hidrólise enzimática de casca de coco verde após pré-tratamento ácido/alcalino e com peróxido de hidrogênio alcalino |
| title_full_unstemmed |
Avaliação da influência de surfactantes químico e biológico na hidrólise enzimática de casca de coco verde após pré-tratamento ácido/alcalino e com peróxido de hidrogênio alcalino |
| title_sort |
avaliação da influência de surfactantes químico e biológico na hidrólise enzimática de casca de coco verde após pré-tratamento ácido/alcalino e com peróxido de hidrogênio alcalino |
| publisher |
Universidade Federal do Rio Grande do Norte |
| publishDate |
2016 |
| url |
https://repositorio.ufrn.br/jspui/handle/123456789/21179 |
| work_keys_str_mv |
AT araujocynthiakerziacostade avaliacaodainfluenciadesurfactantesquimicoebiologiconahidroliseenzimaticadecascadecocoverdeapospretratamentoacidoalcalinoecomperoxidodehidrogenioalcalino |
| _version_ |
1773966038504833024 |
| spelling |
ri-123456789-211792017-11-02T23:59:10Z Avaliação da influência de surfactantes químico e biológico na hidrólise enzimática de casca de coco verde após pré-tratamento ácido/alcalino e com peróxido de hidrogênio alcalino Araújo, Cynthia Kérzia Costa de Santos, Everaldo Silvino dos http://lattes.cnpq.br/8915179413315274 http://lattes.cnpq.br/4330639792072559 Macedo, Gorete Ribeiro de http://lattes.cnpq.br/3324083094904117 Gonçalves, Fabiano Avelino http://lattes.cnpq.br/4600955286343582 Sousa Júnior, Francisco Canindé de http://lattes.cnpq.br/3721560802857426 Ramnolipídeos Triton X-100 Celulose Casca de coco verde Pré-tratamento CNPQ::ENGENHARIAS::ENGENHARIA QUIMICA In Brazil many types of bioproducts and agroindustrial waste are generated currently, such as cacashew apple bagasse and coconut husk, for example. The final disposal of these wastes causes serious environmental issues. In this sense, waste lignocellulosic content, as the shell of the coconut is a renewable and abundant raw material in which its use has an increased interest mainly for the 2nd generation ethanol production. The hydrolysis of cellulose to reducing sugars such as glucose and xylose is catalysed by a group of enzymes called cellulases. However, the main bottleneck in the enzymatic hydrolysis of cellulose is the significant deactivation of the enzyme that shows irreversible adsorption mechanism leading to reduction of the cellulose adsorption onto cellulose. Studies have shown that the use of surfactants can modify the surface property of the cellulose therefore minimizing the irreversible binding. The main objective of the present study was to evaluate the influence of chemical and biological surfactants during the hydrolysis of coconut husk which was subjected to two pre-treatment in order to improve the accessibility of the enzymes to the cellulose, removing this way, part of the lignin and hemicellulose present in the structure of the material. The pre-treatments applied to coconut bagasse were: Acid/Alkaline using 0.6M H2SO4 followed by 1M NaOH, and the one with Alkaline Hydrogen Peroxide at a concentration of 7.35% (v/v) and pH 11.5. Both the material no treatment and pretreated were characterized using analysis of diffraction X-ray (XRD), Scanning Electron Microscopy (SEM) and methods established by NREL. The influence of both surfactants, chemical and biological, was used at concentrations below the critical micelle concentration (CMC), and the concentrations equal to the CMC. The application of pre-treatment with coconut residue was efficient for the conversion to glucose, as well as for the production of total reducing sugars, it was possible to observe that the pretreatment fragmented the structure as well as disordered the fibers. Regarding XRD analysis, a significant increase in crystallinity index was observed for pretreated bagasse acid/alkali (51.1%) compared to the no treatment (31.7%), while that for that treated with PHA, the crystallinity index was slightly lower, around 29%. In terms of total reducing sugars it was not possible to observe a significant difference between the hydrolysis carried out without the use of surfactant compared to the addition of Triton and rhamnolipid. However, by observing the conversions achieved during the hydrolysis, it was noted that the best conversion was using the rhamnolipíd for the husk pretreated with acid/alkali, reaching a value of 33%, whereas using Triton the higher conversion was 23.8%. The coconut husk is a residue which can present a high potential to the 2nd generation ethanol production, being the rhamonolipid a very efficient biosurfactant for use as an adjuvant in the enzymatic process in order to act on the material structure reducing its recalcitrance and therefore improving the conditions of access for enzymes to the substrate increasing thus the conversion of cellulose to glucose. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) “No Brasil são gerados diversos tipos de subprodutos e resíduos agroindustriais como: bagaço de pedúnculo de caju, bagaço de cana-de-açúcar, bagaço de coco e outros. A disposição final desses resíduos, ou seja, sua eliminação causa sérios problemas ambientais. Apesar de uma parte ser utilizada para fins diversos, uma grande quantidade ainda permanece sem utilização. Neste sentido, os resíduos de conteúdo lignocelulósico, como a casca do coco verde, constituem uma matéria-prima renovável e abundante cujo aproveitamento é desejável e tem provocado um interesse crescente para o uso na cadeia de produção de etanol de 2ª geração. Neste trabalho foi utilizada como matéria-prima a casca de coco verde, a qual foi submetida a dois pré-tratamentos com o objetivo de melhorar a acessibilidade das enzimas à celulose. Os pré-tratamentos aplicados ao bagaço de coco foram: Ácido/Alcalino utilizando H2SO4 0,6M e, em seguida, NaOH 1M e, o pré-tratamento com Peróxido de Hidrogênio Alcalino (PHA) a uma concentração de 7,35% (v/v) e pH 11,5. O objetivo principal do estudo em questão, foi avaliar a influência do biossurfactante (ramnolipídeo produzido pela Pseudomonas aeruginosa), durante a hidrólise da casca de coco verde. Para efeito de comparação, foram realizadas hidrólises utilizando surfactante químico, nesse caso o Triton X-100, e hidrólises sem adição de surfactantes. Dessa forma, observou-se que, com a aplicação de ambos os pré-tratamentos, foi possível atingir uma maior conversão de celulose ao comparar com o material in natura. No entanto, ao analisar os resultados obtidos para o processo de hidrólise com a aplicação de surfactantes, verificou-se que o ramnolipídeo produzido melhora, consideravelmente, a conversão celulósica da casca de coco verde, atingindo uma conversão de 33% após 72 horas de hidrólise, enquanto que, a conversão máxima atingida com o uso do Triton X-100 foi de 23%. Esses resultados mostram que o biossurfactante pode ser aplicado na hidrólise enzimática de materiais lignocelulósicos, de modo a apresentar uma boa influência no processo.” 2016-08-18T22:50:18Z 2016-08-18T22:50:18Z 2016-03-18 masterThesis ARAÚJO, Cynthia Kérzia Costa de. Avaliação da influência de surfactantes químico e biológico na hidrólise enzimática de casca de coco verde após pré-tratamento ácido/alcalino e com peróxido de hidrogênio alcalino. 2016. 81f. Dissertação (Mestrado em Engenharia Química) - Centro de Tecnologia, Universidade Federal do Rio Grande do Norte, Natal, 2016. https://repositorio.ufrn.br/jspui/handle/123456789/21179 por Acesso Aberto application/pdf Universidade Federal do Rio Grande do Norte Brasil UFRN PROGRAMA DE PÓS-GRADUAÇÃO EM ENGENHARIA QUÍMICA |