A CORN STEM AS BIOMATERIAL FOR SACCHAROMYCES CEREVISIAE CELLS IMMOBILIZATION FOR THE ETHANOL PRODUCTION

This study provides a preliminary contribution to the development of a bioprocess for the production of ethanol using Saccharomyces cerevisiae cells immobilized onto a corn stem. For this purpose, the yeast cells were submitted to the batch tests in situ adsorption onto 0.5 cm long corn stem. Cells immobilization was analyzed by optical microscopy The number of the yeast cells, fermentation kinetics, the ethanol yield in the presence or the absence of the support in the fermentation medium was investigated. It was determined that the addition of the corn stem led to the abrupt increase of the yeast cells number in substrate, ethanol yield pH value, a total dissolved salts content and substrate conductivity. The addition of 5 and 10g of the corn stem pith per liter of the medium decreased the amount of residual sugar. The results indicate that a corn stem might be a good carder for the yeast cell immobilization, and also a cheap alternative recourse of mineral components with the possibility of application for improving ethanol productivites.