Simultaneous saccharification and fermentation of cassava stems

This research evaluates the effects of the inoculum size and enzymatic activity on the concentration of ethanol obtained through the simultaneous saccharifi cation and fermentation of alkali-pretreated cassava stems. Other goals for this study include the determination and validation of the optimal...

Full description

Autores:
Castaño Peláez, Hader Ivan
Reales Alfaro, Juan
Zapata Montoya, José Edgar
Tipo de recurso:
Article of journal
Fecha de publicación:
2013
Institución:
Universidad Nacional de Colombia
Repositorio:
Universidad Nacional de Colombia
Idioma:
spa
OAI Identifier:
oai:repositorio.unal.edu.co:unal/37831
Acceso en línea:
https://repositorio.unal.edu.co/handle/unal/37831
http://bdigital.unal.edu.co/27915/
Palabra clave:
Cassava Stems
Saccharification
Fermentation
Ethanol
Optimization
Rights
openAccess
License
Atribución-NoComercial 4.0 Internacional
Description
Summary:This research evaluates the effects of the inoculum size and enzymatic activity on the concentration of ethanol obtained through the simultaneous saccharifi cation and fermentation of alkali-pretreated cassava stems. Other goals for this study include the determination and validation of the optimal conditions for and the evaluation of the process of ethanol production in a bioreactor. Alkaline-pretreated cassava stems were used as the substrate in a solid to liquid ratio of 1:10; the enzymatic complex Accellerase 1500 and the yeast Ethanol Red were evaluated at two levels at a temperature of 38° C and a pH of 4.0 in an Erlenmeyer fl ask. The following were evaluated as process controls: simultaneous saccharification and fermentation of non-pretreated stems and separate saccharifi cation and fermentation of pretreated stems. A regression analysis was conducted, and the resulting model was maximized using genetic algorithms. At the optimal conditions identified in an Erlenmeyer flask, the production of ethanol in a 5-liter bioreactor was subsequently evaluated. An experimental concentration of ethanol of 1.88±0.04% v/v (1.99% v/v simulated optimum) was obtained using an inoculum concentration of 1.59 g/L and an enzyme concentration of 13.3 FPU/g. This value was approximately four times the quantity of ethanol produced without pretreatment or by the separate saccharification and fermentation of pretreated cassava stems. The evaluation of the process in the bioreactor yielded an ethanol concentration 20% less than that reached in the Erlenmeyer flask.