STUDI OF XYLANASE APPLICATION FOR BLEACHING PAPER

• Main Author: Deny Permana, Kusniar
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/34957
• Institution: Institut Teknologi Bandung

Lignin is one of component of wood possessing a function to support strengthening of wood. In paper industry, lignin must be removed in order to make paper brighter, color stable, and strong. Conventional paper bleaching involve chlorine as a bleaching agent. This method has obsolete because it produces residues containing high toxic organic chlorines such as dioxins dan furan that are dangerous for human and environment. Xylan is hemiselulose composed of 1,4-?-D-xylopiranose residues. This hemiselulose can be found in agricultural waste such as corncob. Xylan can be degraded by organism such as termite. This organism can degrade xylan by producing xylanolytic enzymes or from a symbiosis with other organism that can produce those enzymes. Endo-?-1,4-xylanase or endoxylanase is one of main xilanolytic enzymes that degrade complex structure of xylan. Those enzymes are ?-xylosidase, acetylxylanesterase, ?-arabinofuronosidase, and ?-glucuronosidase. Endoxylanase hydrolizes ?-1,4-xylopiranose bond and makes lignin chain more simple. Xylanase and hypochloride as bleaching agents have less effect to environtment. In this research, xylanase was produced from Staphylococcus sp. that isolated from termite Reticulitermes santonensis. Isolates was incubated in medium containing corncob xylan for 22 h. The xylanase concentration obtained was 0.057 mg/mL with specific activity was 3.7 U/mL. Pulp from Acacia mangium was cooked at 165oC for 1.5 hours. In bleaching process, xylanase treatment for A. mangium kraft pulp was done before H0EH1H2 phase, with 10% pulp consistency at 60oC for 60 min, pH 6, and xylanase variations 0; 0,5; 1,0; 1,5; dan 2,0 mg/g pulp. Kappa numbers for each treatment were 17,76; 16,45; 15,29; 14,52 and 16,41 in optimum condition at 60oC for 3 h. Pre-bleaching condition using 1,5 mg xylanase /g pulp showed maximum kappa number reduction. Lignin content in initial process, after pre-bleaching, and bleaching using xilanase treatment was 28,53; 25,66; and 15,29%, respectively. Whereas lignin content in initial process, after pre-bleaching, and bleaching without xilanase treatment was 28,53; 28,36; and 21 67%, respectively.