Bio-conventional bleaching of wheat straw soda-AQ pulp with crude xylanases from SH-1 NTCC-1163 and SH-2 NTCC-1164 strains of Coprinellus disseminatus to mitigate AOX generation.
Two novel cellulase-poor xylanases from Coprinellus disseminatus SH-1 NTCC-1163 (enzyme-A) and SH-2 NTCC-1164 (enzyme-B) produced under solid-state fermentation mitigated kappa number of wheat straw soda-AQ pulps by 24.38 and 27.94% respectively after XE stages. The release of reducing sugars and chromophores was highest for both the enzymes at 10IU/g and reaction time 180min for 55°C at variable consistencies that is, 10% for enzyme-A and 5% for enzyme-B. (A)XECEHH and (B)XECEHH sequences improved brightness by 5.17 and 2.58% respectively at 4.5% chlorine charge. AOX in (A)XECEHH and (B)XECEHH sequences reduced by 56.11 and 55.75% respectively at 4.5% chlorine charge and 68.34 and 67.98% respectively at 2.25% chlorine charge respectively compared to control. Both the enzymes showed improvement in double fold and tear index with a decrease in burst and tensile index. SEM showed peeling, cracking and delamination in fibers due to enzyme treatment thus facilitating the penetration of bleach chemicals.
Singh
Shalini
S
Department of Paper Technology, Indian Institute of Technology Roorkee, Roorkee, India. shalinisingh.iit@gmail.com
Dutt
Dharm
D
Tyagi
C H
CH
Upadhyaya
J S
JS
D000327:Adsorption; D000363:Agaricales / Q000201:enzymology*; D001709:Biotechnology / Q000379:methods*; D057886:Bleaching Agents / Q000378:metabolism*; D002241:Carbohydrates / Q000032:analysis; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism*; D006219:Halogens / Q000302:isolation & purification*; D055595:Mechanical Phenomena; D008855:Microscopy, Electron, Scanning; D010209:Paper; D013997:Time Factors; D014908:Triticum / Q000737:chemistry*; D014783:Viscosity; D014865:Waste Disposal, Fluid
D057886:Bleaching Agents; D002241:Carbohydrates; D006219:Halogens; D043364:Endo-1,4-beta Xylanases