A study of single-step hydrolysis of bagasse with concentrated sulphuric acid for obtaining ethanol and in a modified single step and corresponding technical-economic analysis

This work deals with acid hydrolysis of bagasse in lust one step and in a modified step using concentrated sulphuric acid. The study analysed the influence of three independent variables on the single-step process (reaction time, solid percentage of bagasse and temperature). The highest conversion obtained in single-step hydrolysis was 87.65% fermentative sugars, using 70% sulphuric acid with 2% solids at 50oC for 1 hour. The modified process was carried out based on these results; 97.5% maximum conversion of fermentative sugars was achieved using 30% acid dilution. Concentrated sulphuric acid single-stage hydrolysis of bagasse and in a single modified stage were sublected to technical-economic analysis. Starting from the results obtained experimentally of the process at laboratory level and elevated to a possible plant with a capacity to produce 800 HL alcohol/day. VAN and PRD indices indicated that single-stage concentrated acid hydrolysis (variant 1) having 8,310,659.27 VAN and 3 year PRD was more feasible than the modified process (variant 2) having 3,293,318.69 VAN and 7 year PRD

Estudio de la hidrólisis del bagazo con ácido sulfürico concentrado utilizando dos variantes de una sola etapa y una sola etapa modificada para la obtención de etanol y análisis técnico-económico de dicho proceso.

En este trabalo se realiza a escala de laboratorio el proceso de hidrólisis ácida del bagazo utilizando ácido sulfürico concentrado en una sola etapa y en una etapa modificada. En el estudio se analizó la influencia de tres variables independientes: tiempo de reacción, porcentale de sólidos del bagazo y la temperatura sobre el proceso en una sola etapa. La máxima conversión obtenida para la hidrólisis en una etapa fue de 87,65% de azücares fermentables utilizando ácido sulfürico al 70%, 2% de sólidos y una temperatura de 50oC durante 1 hora de reacción. A partir de estos resultados se realizó el proceso modificado obteniéndose una conversión máxima de 97,5% de azücares fermentables a una dilución del ácido al 30%. Se realizó además un análisis técnico-económico de ambas variantes partiendo de los resultados experimentales obtenidos en cada proceso; los valores fueron calculados para una futura planta con capacidad de producir 800 HL de alcohol/dIa. Los Indices VAN Y PRD indicaron que la hidrólisis ácida concentrada en una sola etapa (variante 1) con un VAN de 8310659.27 y un PRD de tres anos es más factible que el proceso modificado (variante 2) con un VAN de 3293318.69 y un PRD de siete anos.This work deals with acid hydrolysis of bagasse in lust one step and in a modified step using concentrated sulphuric acid. The study analysed the influence of three independent variables on the single-step process (reaction time, solid percentage of bagasse and temperature). The highest conversion obtained in single-step hydrolysis was 87.65% fermentative sugars, using 70% sulphuric acid with 2% solids at 50oC for 1 hour. The modified process was carried out based on these results; 97.5% maximum conversion of fermentative sugars was achieved using 30% acid dilution. Concentrated sulphuric acid single-stage hydrolysis of bagasse and in a single modified stage were sublected to technical-economic analysis. Starting from the results obtained experimentally of the process at laboratory level and elevated to a possible plant with a capacity to produce 800 HL alcohol/day. VAN and PRD indices indicated that single-stage concentrated acid hydrolysis (variant 1) having 8,310,659.27 VAN and 3 year PRD was more feasible than the modified process (variant 2) having 3,293,318.69 VAN and 7 year PRD

Evaluation of hydrodynamic parameters of a fluidized-bed reactor with immobilized yeast

The fluidized bed reactor has successfully been used to perform biotechnological processes addressed to the production of high added value. The present work evaluates hydrodynamic parameters of a bench-scale fluidized bed reactor with cells of the yeast Candida guilliermondii immobilized either in calcium alginate beads or in polyvinyl alcohol (PVA). The effects of the following variables on cell immobilization were evaluated at 30 degrees C and feeding a synthetic medium containing 50 g L-1 xylose: total particle density (cells plus support), terminal velocity, particle drag force, minimum fluidization velocity and bed porosity. According to the results obtained, the reactor was shown to operate like a fixed-bed bioreactor at xi < 0.5 and a fluidized bed bioreactor at xi > 0.5. The maximum flow rate needed to obtain maximum bed fluidization in the reactor was equal to the terminal velocity of the immobilized cell particles. Particles of cells immobilized within these supports showed values of drag coefficient lower than those reported for other high-density supports. The evaluation of these hydrodynamic characteristics lead to an adequate bed fluidization inside the reactor, thus improving oxygen transference and availability in the fermentation medium, making the process more viable for future scale-up. (c) 2008 Society of Chemical Industry

Biotechnological Utilization of Biodiesel-Derived Glycerol for the Production of Ribonucleotides and Microbial Biomass

Ten yeast strains were evaluated concerning their capabilities to assimilate biodiesel-derived glycerol in batch cultivation. The influence of glycerol concentration, temperature, pH and yeast extract concentration on biomass production was studied for the yeast selected. Further, the effect of agitation on glycerol utilization by the yeast Hansenula anomala was also studied. The yeast H. anomala CCT 2648 showed the highest biomass yield (0.30 g g(-1)) and productivity (0.19 g L-1 h(-1)). Citric acid, succinic acid, acetic acid and ethanol were found as the main metabolites produced. The increase of yeast extract concentration from 1 to 3 g L-1 resulted in high biomass production. The highest biomass concentration (21 g L-1), yield (0.45 g g(-1)) and productivity (0.31 g L-1 h(-1)), as well as ribonucleotide production (13.13 mg g(-1)), were observed at 700 rpm and 0.5 vvm. These results demonstrated that glycerol from biodiesel production process showed to be a feasible substrate for producing biomass and ribonucleotides by yeast species.Coordenacao de Aperfeicoamento de Pessoal de Nivel SuperiorCoordenacao de Aperfeicoamento de Pessoal de Nivel SuperiorConselho Nacional de Desenvolvimento Cientifico e TecnologicoConselho Nacional de Desenvolvimento Cientifico e Tecnologic

Supercritical technology as an alternative for biotechnological xylitol purification

Processos biotecnológicos têm sido desenvolvidos e aplicados com sucesso para a obtenção de novos produtos. Entre estes, um em desenvolvimento é o uso de microorganismos que fermentam a xilose da fração hemicelulósica de resíduos agroindustriais à xilitol, um alimento funcional com importantes aplicações industriais. Dentre os resíduos agroindustriais o bagaço de cana-de-açúcar é o mais abundante resíduo lignocelulósico no Brasil, e este não tem sido aproveitado em todo seu potencial devido ao desconhecimento ou a não existência de tecnologias disponíveis para serem prontamente aplicadas, ou têm sido utilizado de forma menos valorizada. Neste contexto a biotecnologia surge como uma via alternativa para geração de produtos de alto valor agregado visando aproveitar estes resíduos em todo seu potencial. Basicamente os processos biotecnológicos podem ser divididos em duas etapas: a etapa do processo em si e a etapa de purificação. Como as etapas de separação, recuperação e purificação constituem uma parte importante do processo biotecnológico, podendo alcançar até 80 % do custo final do produto, este trabalho, por conseguinte, visou à recuperação e purificação de xilitol através do uso de uma tecnologia alternativa, ainda não aplicada com este objetivo, a tecnologia supercrítica. O bioprocesso foi conduzido em um reator de leito fluidizado com células de Candida guilliermondii imobilizadas em alginato de cálcio eficazmente e o processo de purificação do meio fermentado foi realizado em um extrator supercrítico com capacidade de 50mL usando CO2 + etanol como solvente. Foi-se avaliado a influência dos parâmetros: pressão e suporte no processo de purificação, utilizando um planejamento fatorial completo 22 sendo a temperatura e o tempo de residência do solvente com a matriz líquida mantidas constantes. Os resultados preliminares demonstram a potencialidade da utilização da tecnologia supercrítica como uma alternativa para purificar xilitol biotecnológico produzido a partir de bagaço de cana-de-açúcar.Biotechnological processes have been developed and applied successfully to obtain new products. Among these, one in development is the use of microorganisms that ferment xylose from the hemicellulosic fraction of agroindustrial waste to xylitol, a functional food with important industrial applications. Among the agroindustrial waste the sugarcane bagasse is the most abundant lignocellulosic residue in Brazil, and this has not been exploited to its full potential due to ignorance or lack of readily available technology to be applied, or have been used in a less valued. In this context the biotechnology emerges as an alternative route for generation of high-value added products aimed use this waste suitably. Basically the biotechnological processes can be divided in two stages: the stage of the process itself and the purification stage. As the separation, purification and recovery stages are an important part of the biotechnology process, which can reach up to 80% of the final cost of the product, this study therefore aimed the recovery and purification through the use of an alternative technology, not yet applied for this aim, the supercritical technology. The bioprocess was carried out in a fluidized reactor with cells of Candida guilliermondii immobilized in calcium alginate effectively and the purification process was tested in a supercritical extractor with a capacity of 50mL using CO2 + ethanol as solvent. It was evaluated the influence of the parameters: pressure and support in the purification process, using a 22 full factorial design keeping the temperature and residence time of solvent with the liquid matrix constant. The preliminary results showed the potentiality of use supercritical technology as an alternative for biotechnological xylitol purification produced from sugarcane bagasse