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In this study, hemicelluloses were isolated from the apical, middle and basal segments of N. cadamba using a 2N KOH extraction procedure. Chemical composition and structural characterization of the three hemicellulosic fractions obtained were comparatively investigated by a combination of HPLC, GPC, FTIR, 1 H, 13 C, HSQC NMR and TGA techniques. According to the sugar analysis and spectral results, (4-O-methyl) glucuronoxylan was the primary hemicellulose identified in the samples with trace levels of mannan also present. All of the three samples showed spherical polymers in 0.005M sodium phosphate solution (containing 0.02N NaCl). Xylan in the middle and basal segment stems had higher molecular weights. Our findings show that during xylogenesis in N. cadamba, changes are observed in xylan content and molecular weight., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Two novel thermo-alkali-tolerant crude xylanases namely MLK-01 (enzyme-A) and MLK-07 (enzyme-B) from Coprinellus disseminatus mitigated kappa numbers of Anthocephalus cadamba kraft-AQ pulps by 32.5 and 34.38%, improved brightness by 1.5 and 1.6% and viscosity by 5.75 and 6.47% after (A)XE(1) and (B)XE(1)-stages, respectively. The release of reducing sugars and chromophores was the highest during prebleaching of A. cadamba kraft-AQ pulp at enzyme doses of 5 and 10 IU/g, reaction times 90 and 120 min, reaction temperatures 75 and 65°C and consistency 10% for MLK-01 and MLK-07, respectively. MLK-07 was more efficient than MLK01 in terms of producing pulp brightness, improving mechanical strength properties and reducing pollution load. MLK-01 and MLK-07 reduced AOX by 19.51 and 42.77%, respectively at 4% chlorine demands with an increase in COD and colour due to removal of lignin carbohydrates complexes. A. cadamba kraft-AQ pulps treated with xylanases from MLK-01 to MLK-07 and followed by CEHH bleaching at half chlorine demand (2%) showed a drastic reduction in brightness with slight improvement in mechanical strength properties compared to pulp bleached at 4% chlorine demand. MLK-01 reduced AOX, COD and colour by 43.83, 39.03 and 27.71% and MLK-07 by 38.34, 40.48 and 30.77%, respectively at half chlorine demand compared to full chlorine demand (4%). pH variation during prebleaching of A. cadamba kraft-AQ pulps with strains MLK-01 and MLK-07 followed by CEHH bleaching sequences showed a decrease in pulp brightness, AOX, COD and colour with an increase in mechanical strength properties, pulp viscosity and PFI revolutions to get a beating level of 35 ± 1 °SR at full chlorine demand.