Substrates

Enzyme activity was primarily evaluated on an industrial substrate derived from unbleached Norway spruce (Picea abies) through a sulfite pulping pre-treatment termed the BALI^TM process [36, 37], developed at Borregaard AS (Sarpsborg, Norway). The substrate had a glucan content of 88%, while hemicelluloses and acid insoluble lignin comprised the remaining 12%. The substrate was dried at 40°C overnight and the particle size was reduced in a planetary ball mill PM 100 (Retsch, Haan, Germany) followed by sieving through a 0.85 mm screen, to make the substrate amenable to use in small-scale reactions. Enzyme activity was also assessed on the cellulosic model substrates carboxymethyl cellulose (CMC) (Sigma-Aldrich, St. Louis, Missouri, USA), Avicel PH-101 (Sigma-Aldrich), filter paper (Whatman no.1) and phosphoric acid swollen cellulose (PASC) prepared from Avicel PH-101 according to [38], as well as on the hemicellulosic substrates konjac glucomannan (KGM), xylan and tamarind xyloglucan (all from Megazyme, Wicklow, Ireland). Cello-oligomers with degree of polymerization (DP) DP2-DP6 (Megazyme) were used as substrates for evaluating cleavage patterns.