The aim of this research was to produce high reduction sugar component of bioethanol fermentation substrate using E. cottonii
seaweed. The dried E. cottonii was taken from Buton district, South East Sulawesi. The seaweed was hydrolyzed using cellulose
for 24 hours with various enzyme concentrations (19, 36, and 52 AU) and temperatures (40 and 50 °C). The reduction sugar was
analyzed by Nelson-Somogy Method then statistical significance test (t-test) was processed by using SPSS software. The results
showed that the reduction sugar was 8.045 mg/mL, obtained during 12 hours of hydrolysis process using 36 AU cellulose at 50
°C. However, this hydrolysis result was not significantly different (tested by t-test analysis) with the result shown by 19 AU
cellulose enzyme hydrolysis at 50 °C temperature which produce 7.937 mg/mL of reduction sugar component