Produção de etanol 2G a partir de hidrolisados de cascas de arroz por co-cultura de Saccharomyces cerevisiae e Pachysolen tannophilus imobilizadas em alginato de sódio
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Data
2021-04-29
Autores
Bertuci, Marcello Lima
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Universidade Estadual Paulista (Unesp)
Resumo
A produção de uma forma alternativa de combustível que substitua os combustíveis de origem fóssil vem sendo cada vez mais estudada devido aos impactos ambientais gerados pelo seu uso excessivo, bem como, ao esgotamento dessas fontes fósseis de energia. Portanto, o uso dos resíduos agroindustriais pode se tornar uma fonte renovável de energia, além de diminuir impactos ambientais. O objetivo deste trabalho foi produzir bioetanol de segunda geração como alternativa aos combustíveis fósseis. Para isso, a casca de arroz foi submetida a hidrolise ácida (fonte de carbono) para produção dos açúcares fermentescíveis a serem utilizados pelo consórcio de leveduras Saccharomyces cerevisiae e Pachysolen tannophilus. Na preparação dos hidrolisados foi utilizado ácido sulfúrico (H2SO4), nas concentrações de 1,0; 2,0; 3,0; 4,0 e 5,0% v/v nos períodos de 5, 10 e 15 minutos de aquecimento a 121°C em autoclave e 12 e 24 horas em temperatura ambiente. Após foi realizada a desintoxicação desses hidrolisados com carvão ativado. A hidrolise ácida de 2% v/v e o tempo de aquecimento de 10 minutos apresentaram as concentrações de açúcares redutores de 33,00 mg/mL para o hidrolisado e 30,36 mg/mL após a desintoxicação. A melhor produção de etanol com Saccharomyces cerevisiae foi utilizando o meio sintético (20,6 mg/mL) e para a levedura Pachysolen tannophilus a maior produção foi de 11,67 mg/mL de meio sintético. O consorcio das duas leveduras se mostrou eficiente com uma maior produção de etanol chegando a 21,5 mg/mL no meio sintético. Os meios hidrolisados e desintoxicados mostraram grande potencial para produção de etanol 18,65 mg/mL e 19,34 mg/mL respectivamente em consorcio, tal como a imobilização em alginato de sódio que se mostrou eficiente em melhorar o potencial da fermentação.
The production of an alternative form of fuel that replaces fossil fuels has been increasingly studied due to the environmental impacts generated by its excessive use, as well as the depletion of these fossil energy sources. Therefore, the use of agro-industrial waste can become a renewable source of energy, in addition to reducing environmental impacts. The objective of this work was to produce second generation bioethanol as an alternative to fossil fuels. For this, the rice husk was subjected to acid hydrolysis (carbon source) to produce fermentable sugars to be used by the yeast consortium Saccharomyces cerevisiae and Pachysolen tannophilus. In the preparation of the hydrolysates, sulfuric acid (H2SO4) was used, in concentrations of 1.0; 2.0; 3.0; 4.0 and 5.0% v/v in the periods of 5, 10 and 15 minutes of heating at 121°C in an autoclave and 12 and 24 hours at room temperature. Afterwards, the detoxification of these hydrolysates with activated carbon was carried out. The acid hydrolysis of 2% v/v and the heating time of 10 minutes showed the concentrations of reducing sugars of 33.00 mg/mL and 30.36 mg/mL after detoxification. The best ethanol production with Saccharomyces cerevisiae was using the synthetic medium (20.6 mg/mL) and for the yeast Pachysolen tannophilus the highest production was 11.67 mg/mL. The intercropping of the two yeasts proved to be efficient with a greater production of ethanol reaching 21.5 mg/mL in the synthetic medium. The hydrolyzed and detoxified media showed great potential for ethanol production 18.65 mg/mL and 19.34 mg/mL respectively in consortium, such as immobilization in sodium alginate, which proved to be efficient in improving the fermentation potential.
The production of an alternative form of fuel that replaces fossil fuels has been increasingly studied due to the environmental impacts generated by its excessive use, as well as the depletion of these fossil energy sources. Therefore, the use of agro-industrial waste can become a renewable source of energy, in addition to reducing environmental impacts. The objective of this work was to produce second generation bioethanol as an alternative to fossil fuels. For this, the rice husk was subjected to acid hydrolysis (carbon source) to produce fermentable sugars to be used by the yeast consortium Saccharomyces cerevisiae and Pachysolen tannophilus. In the preparation of the hydrolysates, sulfuric acid (H2SO4) was used, in concentrations of 1.0; 2.0; 3.0; 4.0 and 5.0% v/v in the periods of 5, 10 and 15 minutes of heating at 121°C in an autoclave and 12 and 24 hours at room temperature. Afterwards, the detoxification of these hydrolysates with activated carbon was carried out. The acid hydrolysis of 2% v/v and the heating time of 10 minutes showed the concentrations of reducing sugars of 33.00 mg/mL and 30.36 mg/mL after detoxification. The best ethanol production with Saccharomyces cerevisiae was using the synthetic medium (20.6 mg/mL) and for the yeast Pachysolen tannophilus the highest production was 11.67 mg/mL. The intercropping of the two yeasts proved to be efficient with a greater production of ethanol reaching 21.5 mg/mL in the synthetic medium. The hydrolyzed and detoxified media showed great potential for ethanol production 18.65 mg/mL and 19.34 mg/mL respectively in consortium, such as immobilization in sodium alginate, which proved to be efficient in improving the fermentation potential.
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Palavras-chave
Hidrólise ácida, Consórcio, Resíduos agroindustriais, Bioetanol, Acid hydrolysis, Consortium, Agroindustrial waste, Bioethanol