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Avalia??o da influ?ncia de surfactantes qu?mico e biol?gico na hidr?lise enzim?tica de casca de coco verde ap?s pr?-tratamento ?cido/alcalino e com per?xido de hidrog?nio alcalinoAra?jo, Cynthia K?rzia Costa de 18 March 2016 (has links)
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Previous issue date: 2016-03-18 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / ?No Brasil s?o gerados diversos tipos de subprodutos e res?duos agroindustriais como: baga?o de ped?nculo de caju, baga?o de cana-de-a??car, baga?o de coco e outros. A disposi??o final desses res?duos, ou seja, sua elimina??o causa s?rios problemas ambientais. Apesar de uma parte ser utilizada para fins diversos, uma grande quantidade ainda permanece sem utiliza??o. Neste sentido, os res?duos de conte?do lignocelul?sico, como a casca do coco verde, constituem uma mat?ria-prima renov?vel e abundante cujo aproveitamento ? desej?vel e tem provocado um interesse crescente para o uso na cadeia de produ??o de etanol de 2? gera??o. Neste trabalho foi utilizada como mat?ria-prima a casca de coco verde, a qual foi submetida a dois pr?-tratamentos com o objetivo de melhorar a acessibilidade das enzimas ? celulose. Os pr?-tratamentos aplicados ao baga?o de coco foram: ?cido/Alcalino utilizando H2SO4 0,6M e, em seguida, NaOH 1M e, o pr?-tratamento com Per?xido de Hidrog?nio Alcalino (PHA) a uma concentra??o de 7,35% (v/v) e pH 11,5. O objetivo principal do estudo em quest?o, foi avaliar a influ?ncia do biossurfactante (ramnolip?deo produzido pela Pseudomonas aeruginosa), durante a hidr?lise da casca de coco verde. Para efeito de compara??o, foram realizadas hidr?lises utilizando surfactante qu?mico, nesse caso o Triton X-100, e hidr?lises sem adi??o de surfactantes. Dessa forma, observou-se que, com a aplica??o de ambos os pr?-tratamentos, foi poss?vel atingir uma maior convers?o de celulose ao comparar com o material in natura. No entanto, ao analisar os resultados obtidos para o processo de hidr?lise com a aplica??o de surfactantes, verificou-se que o ramnolip?deo produzido melhora, consideravelmente, a convers?o celul?sica da casca de coco verde, atingindo uma convers?o de 33% ap?s 72 horas de hidr?lise, enquanto que, a convers?o m?xima atingida com o uso do Triton X-100 foi de 23%. Esses resultados mostram que o biossurfactante pode ser aplicado na hidr?lise enzim?tica de materiais lignocelul?sicos, de modo a apresentar uma boa influ?ncia no processo.? / 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 rhamnolip?d 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.
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Recupera??o e purifica??o de ramnolip?deos produzidos por pseudomonas aeruginosa P029-GVIIA utilizando mela?o de cana como substratoOliveira, Ana Carmen dos Santos Mendes de 29 December 2010 (has links)
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Previous issue date: 2010-12-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Biosurfactants are molecules produced by microorganisms mainly bacteria as
Pseudomonas and Bacillus. Among the biosurfactants, rhamnolipids play an important
role due to their tensoactive as well as emulsifying properties. Besides can be produced
in a well consolidated way the production costs of biosurfactants are quite expansive
mainly if downstream processing is goning to be considered. Actually, attention has
been given to identification of biosurfactants as well as optimization of its fermentative
processes including downstream ones. This work deals with the development of
strategies to recovery and purification of rhamnolipids produced by Pseudomonas
aeruginosa P029-GVIIA using sugar-cane molasses as substrate. Broth free of cells was
used in order to investigate the best strategies to recovery and purification produced by
this system. Between the studied acids (HCl and H2SO4) for the acid precipitation step,
HCl was the best one as has been showed by the experimental design 24. Extraction has
been carried out using petroleum ether and quantification has been done using the
thioglycolic acid method. Adsorption studies were carried out with activated carbon in a
batch mode using a 24 experimental design as well as combined with an hydrophobic
resin Streamline Phenyl aiming to separate the produced biosurfactant. Biosurfactant
partial identification was carried out using High Performance Liquid Chromatography
(HPLC). Experiments in batch mode showed that adsorption has been controlled mainly
by pH and temperature. It was observed a reduction of 41.4% for the liquid phase and
the solid phase it was possible to adsorb up to 15 mg of rhamnolipd/g of activated
carbon. The kinetics of adsorption has been well fitted to a pseudo-first order reaction
with velocity constant (k1) of 1.93 x 10-2 min-1. Experiments in packed bed ranging
concentration on eluent (acetone) has been shown the highest recovery factor of 98%
when pure acetone has been used. The combined effect if using activated carbon with an
hydrophobic resin Streamline Phenyl has been shown successful for the rhamnolipids
purification. It has been possible to purify a fraction of the crude broth with 98% of
purity when the eluted of activated carbon packed bed was used with pure acetone / Os biossurfactantes s?o produzidos por microrganismos, principalmente,
bact?rias do tipo Pseudomonas e Bacillus. Entre os biossurfactantes, o rhamnolip?deo ? o mais
estudado devido as suas propriedades tensoativas e emulsificantes. Apesar do processo
biotecnol?gico de produ??o de biossurfactante, j? tenha sido estabelecido h? alguns anos, o
alto custo de produ??o e o caro processo de downstream t?m impedido sua ampla utiliza??o.
Deste modo, os ?ltimos estudos est?o concentrados na identifica??o de potenciais
surfactantes, na avalia??o de suas propriedades e na otimiza??o dos processos fermentativos
para sua produ??o, bem como das etapas de purifica??o. Assim, o presente estudo tem como
objetivo desenvolver estrat?gias para a recupera??o e purifica??o de ramnolip?deos
produzidos por Pseudomonas aeruginosa P029-GVIIA utilizando mela?o de cana como
substrato. Com o caldo fermentado livre de c?lulas estudou-se as melhores t?cnicas de
recupera??o e purifica??o do biossurfactante produzido para este sistema. Dentre os ?cidos
estudados (HCl e H2SO4) para a etapa de precipita??o ?cida o HCl foi o que obteve melhor
resultado atrav?s de um planejamento experimental 24. A extra??o foi realizada com o ?ter de
petr?leo e a quantifica??o atrav?s do m?todo do ?cido tioglic?lico. Estudos de adsor??o foram
realizados com carv?o ativado tanto em batelada atrav?s de um planejamento experimental 24
como em leito fixo com carv?o ativado e o seu efeito combinado com uma resina de intera??o
hidrof?bica Streamline Phenyl, com a finalidade de separar o biossurfactante produzido. Para
a identifica??o parcial foi utilizada a cromatografia l?quida de alta efici?ncia (CLAE). Os
ensaios em batelada mostraram que a adsor??o ? governada pelo pH e pela temperatura. A
redu??o da concentra??o de ramnolip?deo para a fase liquida foi de 41,4% e para a fase s?lida,
foi poss?vel adsorver os biossurfactantes na propor??o de 15 mg de ramnolip?deo/ g de carv?o.
A cin?tica em batelada foi ajustada ao modelo cin?tico de pseudo-primeira ordem obtendo o
valor da constante de velocidade k1= 1,93 x 10-2 min.-1. Os ensaios em leito fixo variando a
concentra??o da acetona (eluente), obteve fator de recupera??o de ramnolip?deo de 98% de
recupera??o foi para a acetona pura. O efeito combinado em leito fixo do carv?o ativado com
a resina de intera??o hidrof?bica mostrou-se eficiente na purifica??o de ramnolip?deos. Foi
poss?vel purificar uma fra??o do caldo bruto, cuja pureza atingiu 98% ao se utilizar o eluido
do carv?o ativado com acetona pura
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