New xylanases to obtain modified eucalypt fibres with high-cellulose content.
Modified fibres with high-cellulose content were obtained with two new bacterial xylanases from families 11 and 5. These xylanases were applied separately or simultaneously in a complete ECF (Elemental Chlorine Free) bleaching sequence. Both xylanases improved delignification and bleaching during the sequence and a synergistic effect of the enzymes was observed on several pulp and paper properties. The xylanases boosted the release of xylooligosaccharides branched with hexenuronic acids (HexA), giving rise to fibres with a reduced HexA and xylose content. However, these effects depended on the xylanase used, being the family 11 enzyme more efficient than the family 5 xylanase. Effluent properties such as absorbance spectra UV/Vis, COD and colour were affected by the enzymatic sequences as a consequence of the dissolution of lignin and xylooligosaccharides. Some changes in the fibre morphology were also produced without affecting the final paper strength properties.
Valls
Cristina
C
Textile and Paper Engineering Department, ETSEIAT, Universitat Politècnica de Catalunya, Terrassa, Spain.
Gallardo
Oscar
O
Vidal
Teresa
T
Pastor
Francisco Ignacio Javier
FI
Díaz
Pilar
P
Roncero
M Blanca
MB
D002482:Cellulose / Q000032:analysis*; D003116:Color; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism*; D005052:Eucalyptus / Q000737:chemistry*; D006603:Hexuronic Acids / Q000032:analysis; D008031:Lignin / Q000032:analysis; D010100:Oxygen / Q000032:analysis; D010209:Paper; D011134:Polysaccharides / Q000032:analysis / Q000737:chemistry; D013057:Spectrum Analysis; D014783:Viscosity; D014865:Waste Disposal, Fluid
D006603:Hexuronic Acids; D011134:Polysaccharides; C095263:hexenuronic acid; C007916:hemicellulose; D002482:Cellulose; D008031:Lignin; D043364:Endo-1,4-beta Xylanases; D010100:Oxygen