Fig. 4
HPAEC-PAD chromatogram showing oligosaccharides released by KpLPMO10A from beechwood xylan after 16 h at 37 °C. Blank reactions were carried out with buffer, xylan and ascorbic acid. Peaks of native (Xyl3–Xyl6) xylo-oligosaccharides were assigned based on a standard (Megazyme Inc.) (a). MALDI-TOF MS data. The inset shows the sodiated forms of DP5, m/z 701.213 (native); lactone or ketoaldose, m/z 699.209 (− 2 Da) and aldonic acid or gemdiol, m/z 717.200 (+ 16 Da). No peaks related to the sodium adduct of the sodium salt of aldonic acid (m/z 739.213) were observed. m/z 715.200 (+ 14 Da) was assumed as the potassium adduct of native DP5 (and not an indicative of double oxidation) given that no C1-oxidized species are produced by KpLPMO10A (see Additional file 6: Figure S5) (b). Synergy of KpLPMO10A and LPMO9 (an strictly cellulose-oxidizing LPMO) with the endo-β-1,4-xylanase xynB/XAC4254 (c). Synergy experiments were carried out with beechwood xylan as substrate at 37 °C during 24 h/1000 rpm. Control reactions were done with only xynB or KpLPMO10A or LPMO9. Bars with different letters mean statistical difference at 0.05 significance by Tukey test