Immobilization of Zymomonas mobilis and amyloglucosidase for ethanol production from sago starch

Abstract

Immobilization of amyloglucosidase (AMG) and Zymomonas mobilis cells was studied in order to produce ethanol from sago starch economically. Among various immobilization methods tested, a coimmobilized system using chitin and sodium alginate appeared most promising with respect to ethanol productivity and operational stability. When the system was run in the continuous simultaneous saccharification and fermentation (SSF) mode, the maximum ethanol productivity was found to be 72.2 g l-1 h-1 at a dilution rate of 3.28 h-1. This system could be run in the stable manner over 40 days with a steady-state ethanol concentration of 44 g l-1 and an ethanol conversion yield of 93%.