Caracterização das condições fermentativas da levedura Pichia membranifaciens para produção de etanol de segunda geração
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Data
2019-03-07
Autores
Ribeiro, Natália Novais
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Tecnologias desenvolvidas na última década tornaram viável o uso de materiais lignocelulósicos para produção de etanol. Entretanto para aumento do rendimento fermentativo são necessárias algumas melhorias, entre elas destaca-se a busca por novos microrganismos capazes de fermentar açúcares com cinco carbonos. Neste sentido, o presente trabalho teve como objetivo avaliar a influência do pH, temperatura e suplementação de nutrientes sobre a fermentação de pentoses e hexoses por Pichia membranifaciens LJ04 em mostos sintéticos e comparar o desenvolvimento de processos fermentativos conduzidos em licores sintéticos e licor hemicelulósico concentrado e destoxificado nas condições fermentativas ideais. No primeiro ensaio, os tratamentos principais foram caracterizados pelas temperaturas 32°C, 37°C e 40°C nos pHs 3,5, 4,0 e 4,5 e os secundários pelos tempos 0, 6, 12 e 24h. No segundo ensaio, os tratamentos principais foram caracterizados pela suplementação com N, P, K, Mg, Mn e Zn associados e isolados e os secundários pelos tempos 0, 6, 12 e 24 h. Para o terceiro ensaio, os tratamentos principais foram caracterizados pelos mostos sintéticos com diferentes suplementações de nutrientes e licor hemicelulósico concentrado e destoxificado e os secundários pelos tempos 0, 6, 12, 24, 48 e 72 h. Estabeleceu-se neste estudo que os parâmetros ideais para produção de etanol foram temperatura de 32°C e pH 4,5, nestas condições obteve-se altas taxas de viabilidade celular, índice de brotamento e viabilidade dos brotos e a maior concentração de etanol após o período de 24h do processo fermentativo. A presença de nitrogênio, fósforo, potássio, magnésio, manganês e zinco mostraram-se essenciais para conservação e crescimento das células de leveduras e alta produção de etanol. O trabalho mostrou que é possível a produção de etanol por Pichia membranifaciens em mostos sintéticos e licor hemicelulósico. O licor hemicelulósico foi o tratamento que obteve o maior consumo de xilose ao longo das 72h do processo fermentativo.
Technologies developed in the last decade have made the use of lignocellulosic materials viable for ethanol production. However, to increase the fermentative yield some improvements are necessary, through the search of new microorganisms with the ability to ferment sugars with five carbons. Thus, the present research evaluated the influence of pH, temperature and nutrient supplementation on the fermentation of pentoses and hexoses by Pichia membranifaciens LJ04 in synthetic medium and to compare the fermentative processes in synthetic hydrolysate and hemicellulosic hydrolysate (detoxified) in optimum fermentative conditions. In the first trial, the main treatments were the temperature 32°C, 37°C and 40°C at pHs 3.5, 4.0 and 4.5 and the secondary treatments the times 0, 6, 12 and 24 hours. In the second trial, the main treatments were nutrient supplementation with N, P, K, Mg, Mn and Zn associated and isolated and the secondary treatments the times 0, 6, 12 e 24 h. For the third trial, the main treatments were the synthetic medium with different nutrient supplements and hemicellulosic hydrolysate (detoxified), and secondary treatments to the times 0, 6, 12, 24, 48 and 72 h. It was established in this study that the ideal parameters for ethanol production were a temperature of 32 ° C and pH 4.5, with these conditions it was obtained high rates of cell viability, budding rate, and bud viability, and the highest concentration of ethanol after the 24 hours of the fermentation process. The presence of nitrogen, phosphorus, potassium, magnesium, manganese and zinc was essential for the conservation and growth of yeast cells and high ethanol production. The work showed that it is possible to produce ethanol by Pichia membranifaciens in synthetic medium and hemicellulosic hydrolysate. The hemicellulosic hydrolysate was the treatment that obtained the highest consumption of xylose during the 72 hours of the fermentation process.
Technologies developed in the last decade have made the use of lignocellulosic materials viable for ethanol production. However, to increase the fermentative yield some improvements are necessary, through the search of new microorganisms with the ability to ferment sugars with five carbons. Thus, the present research evaluated the influence of pH, temperature and nutrient supplementation on the fermentation of pentoses and hexoses by Pichia membranifaciens LJ04 in synthetic medium and to compare the fermentative processes in synthetic hydrolysate and hemicellulosic hydrolysate (detoxified) in optimum fermentative conditions. In the first trial, the main treatments were the temperature 32°C, 37°C and 40°C at pHs 3.5, 4.0 and 4.5 and the secondary treatments the times 0, 6, 12 and 24 hours. In the second trial, the main treatments were nutrient supplementation with N, P, K, Mg, Mn and Zn associated and isolated and the secondary treatments the times 0, 6, 12 e 24 h. For the third trial, the main treatments were the synthetic medium with different nutrient supplements and hemicellulosic hydrolysate (detoxified), and secondary treatments to the times 0, 6, 12, 24, 48 and 72 h. It was established in this study that the ideal parameters for ethanol production were a temperature of 32 ° C and pH 4.5, with these conditions it was obtained high rates of cell viability, budding rate, and bud viability, and the highest concentration of ethanol after the 24 hours of the fermentation process. The presence of nitrogen, phosphorus, potassium, magnesium, manganese and zinc was essential for the conservation and growth of yeast cells and high ethanol production. The work showed that it is possible to produce ethanol by Pichia membranifaciens in synthetic medium and hemicellulosic hydrolysate. The hemicellulosic hydrolysate was the treatment that obtained the highest consumption of xylose during the 72 hours of the fermentation process.
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Palavras-chave
Hidrolisado, Licor hemicelulósico, Licor sintético, Pentose, Pichia spp, Hydrolysate, Hemicellulosic liquor, Synthetic Liquor