Scale Up of Ethanol Production Using Pulp Mill Wastewater Sludge by Cellulase and Saccharomyces Cerevisiae

Abstract

This study aimed to evaluate the potential use of pulp mill wastewater sludge as substrate in ethanol production. The simultaneous saccharification and fermentation process was conducted by using Saccharomyces cerevisiae TISTR 5339 under optimum proportion of cellulase and pulp mill wastewater sludge. The ethanol production from cellulosic materials in simultaneous saccharification and fermentation needs cooperation between cellulase and yeast. The cellulase hydrolyzes cellulose to sugar while yeast utilizes sugar to produce ethanol. The pulp mill wastewater sludge has an average content of 73.3% hemi cellulose, 67.1% alpha cellulose, 4.7% beta cellulose and 1.4% gramma cellulose. The experimental results indicated that the volume of the ethanol tend to increase with time, providing the maximum ethanol yield of 0.69 g/g on the 7th day, the last day of the experiment. The ethanol production was scaled up in 5 L fermentor under optimum proportion and increased the fermentation period. It was found that the ethanol production gave the maximum ethanol yield of 1.14 g/g on the 9 th day of the totally 13 days experimentation. These results showed that the cellulose from pulp mill wastewater sludge was as effective substrate for ethanol production and alternative energy for the future. Keywords: Pulpmill wastewater sludge, Cellulase, Saccharomyces cerevisiae, Saccharification, Simultaneous fermentation.