Cassava waste can be utilized to produce ethanol due to its containing cellulose and
hemi-cellulose at levels of 24.99 and 6.67 % (w/w) respectively. A cassava pretreatment
method using enzymatic and acid hydrolysis for converting starch into fermentable sugars
was investigated. The cassava waste was hydrolyzed by using 0.2-5.0 M sulfuric acid
(H2SO4) at a temperature of 60-120o
C for 30 min. It was found that the maximum reducing
sugar obtained at 6.1% (w/v) using a cassava waste to acid ratio of 1:2 (w/v) at 0.6 M H2SO4
and 120o
C. While the maximum reducing sugar obtained in this study was at 6.2% (w/v),
using a mixture of cellulase and pectinase at pH 4.5, 28o
C for 1 hr followed by α-amylase at
pH 5.5, 100o
C for 2 hrs and finally glucoamylase at pH 4.5, 60o
C for 24 hrs. This is the
optimum condition for cassava waste pretreatment using enzymatic hydrolysis. It was also
found that the maximum ethanol production using Saccharomyces cerevisiae TISTR 5596
from enzymatic hydrolyzed sugar at initial reducing sugar 8.92% (w/v) was 3.62% (w/v) at
24 hrs of fermentation, corresponding to a 91% theoretical yield.
Key words: Cassava waste, cellulosic pretreatment, ethanol production and