Fig. 2
HPAEC-PAD chromatogram showing oligosaccharides released by KpLPMO10A from PASC after 16 h at 37 °C in the presence or absence of ascorbic acid. Blank reactions were carried out with buffer, PASC and ascorbic acid. Peaks of native (Glc2–Glc6) and oxidized cello-oligosaccharides were assigned based on standard cello-oligosaccharides (Megazyme Inc.) and [57], respectively (a). MALDI-TOF MS data confirmed the release of native and C1/C4-oxidized oligosaccharides from PASC. The inset shows DP7, m/z 1175.314 (native); lactone or ketoaldose, m/z 1173.297 (− 2 Da); aldonic acid or gemdiol, m/z 1191.329 (+ 16 Da) and di-sodiated adduct of aldonic acid, m/z 1213.263 (+ 38 Da). Additionally, m/z 1189.243 (+ 14 Da) and 1211.263 (+ 36 Da) correspond to the double-oxidized products and their sodium adducts, respectively (b). Release of cellobionic acid (GlcGlc1A) from PASC over 24 h at 37 °C/850 rpm (c)