(725b) Cellulase Production from Paper Mill Sludge by Trichoderma Reesei Rut C-30

Paper mill sludge is the waste material generated from the pulping and paper making process. High-glucan/low-lignin content and well-dispersed short fibrous structure make the paper mill sludge a promising feedstock for bioconversion into value-added products. However, it also has a high ash content which is harmful to cell growth. It is desirable to remove ash as much as possible from the sludge, while retaining carbohydrates. In this study, the sludge was de-ashed by centrifugation, and treated additionally by acid and alkali. It was used as substrate for cellulase production and bioconversion to ethanol. The cellulase enzyme produced from de-ashed sludge exhibited cellulase activity as high as 8 FPU/mL. The cellulase enzyme produced in this work was further characterized in terms of specific activity based on mg-protein, and activities of the three major components in cellulase and xylanase. This enzyme was evaluated by simultaneous saccharification and fermentation (SSF) using Sacharomyces cerevisiae. Ethanol yield of 71% of theoretical maximum and 2.8%(w/v) ethanol concentration were achieved. By fed-batch SSF, the ethanol concentraton reached 60 g/L. These results are comparable to those of the process using commercial cellulases. The results of this study indicate that the pulp mill sludge is an attractive feedstock for cellulase as well as ethanol production.