HPAEC elution patterns of RAC incubated with MtLPMO9A and EGI. Regenerated amorphous cellulose (RAC, 2 mg mL−1) before and after incubation with MtLPMO9A (10 mg g−1 substrate) and/or endoglucanase I from T. viride (EGI) (100 μg g−1 substrate). Samples were incubated in a 50 mM ammonium acetate buffer (pH 5.0) for 24 h at 52°C with ascorbic acid addition (1 mM). In the presence of ascorbic acid, mainly oxidized gluco-oligosaccharides (GlcOS
*) are formed by MtLPMO9A from RAC (marked either with # for C1 or * for C4 oxidation). Incubation of EGI with RAC results in hardly detectable non-oxidized gluco-oligosaccharides (DP2-5). The combined addition of EGI and MtLPMO9A results in a 16-fold higher release of non-oxidized GlcOSn (based on comparison of the sum of AUC of GlcOS2-4 determined by HPAEC) from RAC compared to EGI incubated with RAC only.