Application of xylanase from alkaliphilic thermophilic Bacillus sp NCIM 59 in biobleaching of bagasse pulp

Because of environmental concerns, the use of hemicellulolytic enzymes has recently attracted considerable interest as a substitute for chlorine chemicals in pulp bleaching. The cellulase free xylanase from alkaliphilic thermophilic Bacillus sp. NCIM 59 was evaluated for prebleaching of the bagasse pulp. The UV absorption spectrum of the compounds released by enzyme treatment, and after alkali extraction, showed a characteristic peak at 280 nm, indicating the presence of lignin in the released coloring matter. The material released after enzyme treatment also absorbed strongly at 237, 280 and 465 nm. The biotreatment resulted in a 2 unit decrease in the K number without altering the strength properties of the pulp. Subsequently, the peroxide bleaching of the enzyme treated samples resulted in a decrease in the re number by 10 units and an increase in brightness by 2.5%. The viscosities of xylanase treated samples were found to be unaltered.