PRODUCTION OF ETHANOL FROM RECYCLED PAPER SLUDGE USING CELLULASE AND YEAST, KLUVEROMYCES-MARXIANUS

Paper recycling is expected to increase by an average of 10% annually for the next few years. Likewise, the recycled paper sludge (RPS) gene rated during repulping will increase accordingly. The typical RPS has an average content of 60% moisture and 50% cellulose on a dry basis. S imultaneous saccharification and fermentation (SSF) with fungal cellul ase and yeast, Kluyveromyces marxianus, were used to convert cellulose fibers of RPS samples to ethanol. The cellulase loading was 8 filter paper units (FPU)/g dry RPS. About 32 and 35 g/l of ethanol were produ ced from 180 and 190 g/l dry materials, respectively, after 72 h of in cubation. This indicates that at least 72% of cellulose in the RPS was converted into ethanol. During incubation, the thick slurry of RPS wa s liquefied within 24 h, resulting in the reduction of water-holding c apacity (WHC) of RPS to 30-35% of the original. (C) 1997 Elsevier Scie nce Ltd.