at 13741372 cm21 was assigned to aliphatic CH stretching in CH3 and phenOH. The decrease of its relative intensity illustrated that either the side chains or phenOH of lignin decreased after the enzymatic treatment. The decrease in relative intensity at 1266 1252 cm21 indicates degradation of guaiacyl groups. A new band that appeared at 1737 cm21 in P-X-L-C treated pulp was assigned to C = O stretching vibration in b-C = O, COOH, ester indicating that residual lignin after an P-X-L-C 2883-98-9 supplier treatment was enriched in these types of functional groups. New band at 1162 cm21 in P-XL-C treated pulp indicated degradation of syringyl groups. The changes in pulp crystallinity derived from A1430/A897 ratio in accordance with the X-ray diffraction studies. 52.160.6 and 52.860.41% ISO was obtained when sonication was done at 1% consistency, 230 W, 20 kHz for 15 min and when microwaving was done at 5% consistency, 850 W for 1 min. When used in combination with P-X-L-C pretreatment, further 3 and 3.5% increase in brightness to 61.4560.75 and 61.7360.33% ISO was observed. Sonication causes swelling of fibers thus opening them which in turn increased the surface area of contact between fibers and enzymes or chemicals allowing them to reach protected inertial sites. Sonication has been 10646850 used previously for deinking of xerox print pulp showing 26507655 a 10.39% increase in brightness. Microwaving causes steam explosion thereby opening the fibers due to which hemicelluloses and lignin components get exposed to enzymes and chemicals. It is also an efficient, fast, economic, easy and environmental friendly alternative to conventional heating of pulp for enzymatic or chemical bleaching. Microwaving has been explored previously in our lab for delignification of kraft pulp. This study reports for the first time potential of microwave pretreatment for deinking purposes. Physical and Chemical Characterization of ONP Pulp When all the three pretreatments were used together, the combination resulted in 62.1360.5% ISO brightness, 7.460.66 kappa number and 139.04622 ppm ERIC as compared to brightness and ERIC of P-C pulps. Substantial reduction in ERIC to this level with the use of a new sequence combining enzymatic and physical methods for efficient deinking of ONP pulp has not been reported before. Though P-S-MW-X-L-C deinked pulp had lower strength properties than P-X-L-C deinked pulp, yet these were better than those of conventional chemically treated pulp. The breaking length of P-X-L-C deinked pulp was 26, 8.6 and 11% higher; burst factor was 0.6, 1.7 and 0.06% higher and tear factor was 12.1, 3.3 and 5.2% higher than P-X-C, P-L-C and P-S-MW-X-L-C deinked pulp. As none of the enzyme preparations had cellulase activity, a 13% increase in viscosity was observed in P-X-L-C treatment. P-L-C treatment caused 12% reduction in kappa number as compared to P-C, indicating the role of laccase in delignification. Scanning Electron Microscopy for Fiber Morphology As can be observed from Effect of Sonication and Microwaving Pretreatments on Deinking of ONP The parameters for the effect of sonication and microwave pretreatments alone and in combination with P-X-L-C pretreatment of ONP were optimized. Maximum brightness of Deinking of other Wastepaper Pulps Different wastepaper pulps were effectively deinked by using a combination of xylanase and laccase enzymes. Maximum increase 
in brightness was obtained for ONP pulp followed by magazine pulp, inkjet print pulp, laser print pulp and xero