RESUMO

The purpose of the present work was to show, as a first stage, that it is possible to characterize autochtohnous strains of Clostridium acetobutilicum of a good solvent producing capacity, specially N-butanol, through the utilization of suitable techniques for isolating anaerobic microorganisms. Cassava roots were employed as raw material using suitable culture media and an anaerobic jar of cold catalyst. The fermentative capacity of the strains thus isolated was evaluated against a control strain of Clostridium acetobutilicum. Even though some of the strains showed a greater solvent producing power, most of them showed lower fermentation capacity than the control strain, which could be increased, by applying successive thermic treatments. As a second stage, and due to the low cost production of cassava in the Province of Misiones, we studied its utilization as an acetone-butanol fermentation substrate. Mashes composed of binary mixtures of cassava flour and variable amounts of integral flour maize or soy were treated with selected "starters" of Clostridium acetobutilicum, being further processed according to standardized techniques in order to obtain the already mentioned solvents. Mashes concentration influence was also studied using culture media the composition of which proved to be excellent in all experiments carried out under "static system" conditions. The highest fermentative yields (maximum value recorded: 26,20 g of total solvents, with respect to dry solids), were recorded for mashes obtained from mixtures containing integral maize flour; these showed a higher degree of nutrients utilization than those prepared with integral soy flour.

Assuntos

RESUMO

Con el empleo de tecnicas adecuadas para microorganismos anaerobicos, es posible aislar y caracterizar cepas de Clostridium acetobutilicum, buenas productoras de solventes, en especial n-butanol, propanoma y etanol. Se partio de raices de mandioca como materia prima, adoptando el uso de medios de cultivo apropiados y una jarra anaarobica e catalizador frio. Se midio la capacidad fermentativa de las cepas aisladas frente a una cepa testigo de Clostridium acetobutilicum. Si bien algunas de las cepas ensayadas presentaron una mayor produccion de solventes, la mayoria de las mismas exhibieron una menor capacidad fermentativa que el testigo, la que pudo ser incrementada significativamente con el empleo de un numero discreto de tratamientos termicos sucesivos. Se estudio la utilizacion de la mandioca como sustrato en fermentacion acetobutilica. Para ello se trataron mostos formados a partir de mezclas binarias de fecula de mandioca y harinas integrales de maiz y soja, con percultivos de cepas seleccionadas, a fin de obtener solventes de aplicacion industrial: n-butanol y propanona. Los mayores rendimientos fermentativos, hasta 26,20 g en solventes totales, se registraron para mostos suplementativos con harina de maiz.Los medios de cultivo con harina de soja como suplemento proteico mostraron un menor grado de conversion de sustratos en solventes

Assuntos

RESUMO

The purpose of the present work was to show, as a first stage, that it is possible to characterize autochtohnous strains of Clostridium acetobutilicum of a good solvent producing capacity, specially N-butanol, through the utilization of suitable techniques for isolating anaerobic microorganisms. Cassava roots were employed as raw material using suitable culture media and an anaerobic jar of cold catalyst. The fermentative capacity of the strains thus isolated was evaluated against a control strain of Clostridium acetobutilicum. Even though some of the strains showed a greater solvent producing power, most of them showed lower fermentation capacity than the control strain, which could be increased, by applying successive thermic treatments. As a second stage, and due to the low cost production of cassava in the Province of Misiones, we studied its utilization as an acetone-butanol fermentation substrate. Mashes composed of binary mixtures of cassava flour and variable amounts of integral flour maize or soy were treated with selected [quot ]starters[quot ] of Clostridium acetobutilicum, being further processed according to standardized techniques in order to obtain the already mentioned solvents. Mashes concentration influence was also studied using culture media the composition of which proved to be excellent in all experiments carried out under [quot ]static system[quot ] conditions. The highest fermentative yields (maximum value recorded: 26,20 g of total solvents, with respect to dry solids), were recorded for mashes obtained from mixtures containing integral maize flour; these showed a higher degree of nutrients utilization than those prepared with integral soy flour.

RESUMO

Con el empleo de tecnicas adecuadas para microorganismos anaerobicos, es posible aislar y caracterizar cepas de Clostridium acetobutilicum, buenas productoras de solventes, en especial n-butanol, propanoma y etanol. Se partio de raices de mandioca como materia prima, adoptando el uso de medios de cultivo apropiados y una jarra anaarobica e catalizador frio. Se midio la capacidad fermentativa de las cepas aisladas frente a una cepa testigo de Clostridium acetobutilicum. Si bien algunas de las cepas ensayadas presentaron una mayor produccion de solventes, la mayoria de las mismas exhibieron una menor capacidad fermentativa que el testigo, la que pudo ser incrementada significativamente con el empleo de un numero discreto de tratamientos termicos sucesivos. Se estudio la utilizacion de la mandioca como sustrato en fermentacion acetobutilica. Para ello se trataron mostos formados a partir de mezclas binarias de fecula de mandioca y harinas integrales de maiz y soja, con percultivos de cepas seleccionadas, a fin de obtener solventes de aplicacion industrial: n-butanol y propanona. Los mayores rendimientos fermentativos, hasta 26,20 g en solventes totales, se registraron para mostos suplementativos con harina de maiz.Los medios de cultivo con harina de soja como suplemento proteico mostraron un menor grado de conversion de sustratos en solventes

Assuntos