Simultaneous saccharification and fermentation (SSF) process is the ideal method of producing ethanol from paper sludge. In this process, a cellulose hydrolyzing enzyme is combined with an
ethanol producing organism to carry out the simultaneous hydrolysis of cellulose to glucose and conversion of glucose into ethanol in the same reactor. Compared to the separate hydrolysis and fermentation (SHF) steps, the improved hydrolysis rates and yields of ethanol were observed by SSF process [12].