Cassava pulp treated with cellulase following hydrothermal
reaction (140 C for 1 h) was fermented using K7G and K7A
without addition of amylolytic enzymes. As shown in Fig. 4, K7G
produced significant amounts of ethanol from 5%, 10%, 20%, and
30% pulp, while K7A produced very little ethanol (Fig 4). Ethanol
production rate from cassava pulp by K7G without amylase
treatment was slower, especially during the early phase of
fermentation compared to that by K7 with cassava pulp treated
with a-amylase and glucoamylase. The slow ethanol production by
K7G presumably is due to the time required for saccharification of
starch by the glucoamylase displayed on the cell surface. The
fermentation rate by K7G could be easily improved by increasing
initial cell density [12] and by codisplaying a-amylases with glucoamylase
[6].