Application of ultrasound and technical enzymes during bioethanol production from fresh cassava root

The effect of pre-treatment on sugar yield of cassava root as well as application of amylolytic enzymes for conversion of starch to glucose and bioethanol production using yeast were studied. Different pre-treatments. such as ultrasound, sulphuric acid as well as application of technical enzymes (pectolytic/cellulolytic), have effect on starch conversion into glucose. Up to 3% or 8% of free sugar could be observed after ultrasound and technical enzyme treatment, respectively, compared to untreated sample (free sugar 0.5%). Amylolytic enzymes (a-amylase and gluco-amylase) from different companies (Novozymes. Stern. Valley and A B enzymes) investigated in this study were effective to convert starch in glucose. The activity of amylolytic enzymes depended on the concentration of enzymes and treatment time. Up to 100% of starch could be converted in glucose during 3 h saccharification (28.8 g glucose/100 fresh cassava root) and enzyme concentration of 0.1% w/w. Fermentation of enzymatic saccharified cassava starch using Saccharomyces cerevisiae yeast showed the best fermentation condition for cassava root at 30 C and pH 5.0. Up to 11% v/v ethanol could be produced by 3 days fermentation.