Simultaneous saccharification and alcohol fermentation of unheated starch by free, immobilized and coimmobilized systems of glucoamylase and Saccharomyces cerevisiae

Abstract

For the simultaneous saccharification and alcohol fermentation (SSF) of corn, cassava and naked barley requiring no heat treatment, the use of freely syuspended glucoamylase-cell, cell immobilized and glucoamylase-cell coimmobilized systems in Ca-alginate was investigated.

In these systems, 0.2% glucoamylase was used for both the free glucoamylase-cell and cell immobilized systems, whereas 1.0% of the enzyme was used for the glucoamylase cell coimmobilized system.

The SSF of corn, cassava and naked barley was successfully carried out as follows; group A with heat treatment and group B without heat treatment using the glucoamylase-cell suspende system. The conversion yield (Y_p/s0) in the cell immobilized system was increased by the heat treatment of corn and cassava but not of naked barley. The conversion yield was remarkably increased using the coimmobilized system corn and cassava, whereas naked barley gave the same yield as in the free glucoamylase-cell suspended system.