Fig. 8
From: A secretomic view of woody and nonwoody lignocellulose degradation by Pleurotus ostreatus
2D NMR of poplar wood (a, b) and wheat straw (c, d) treated with P. ostreatus (b, d) and controls (a, c). The formulae of the lignin and cinnamic acid structures, whose correlation signals are identified in the different spectra, are shown in the bottom of the figure: A β-O-4′ ether (dark blue); B phenylcoumaran (turquoise); C resinol (purple); PCA p-coumaric acid (light brown); FA ferulic acid (orange); PB p-hydroxybenzoate (pink); T tricin (brown); H p-hydroxyphenyl unit (blue); G guaiacyl unit (green); S syringyl unit (red); S′ α-oxidized syringyl unit (red). The prominent methoxyl signal (MeO, yellow) is also shown in the spectra, together with some selected carbohydrate correlation (C1–H1, C2–H2, and C3–H3) signals (cyan) corresponding to normal and acetylated xylan (X and X′, respectively), uronic acid (U), arabinan (Ar), and glucan units (Gl), α and β reducing ends in xylan (αX1(R) and βX1(R), respectively). List of lignin (and related) signals (δC/δH ppm): 53.2/3.46, Cβ/Hβ in phenylcoumarans (Bβ); 53.6/3.05, Cβ/Hβ in resinols (Cβ); 55.5/3.66, C/H in methoxyls (−OMe); 71.1/4.16 and 3.77, Cγ–Hγ in β–β′ resinols (Cγ); 71.1–71.5/4.72–4.85, Cα/Hα in β–O–4´ ethers (Aα); 84.1/4.24, Cβ/Hβ in β–O–4′ linked to a G unit (Aβ(G)); 84.9/4.59, Cα/Hα in β–β′ resinols (Cα); 86.0/4.08, Cβ/Hβ in β–O–4′ ethers linked to a S unit (Aβ(S)); 86.7/5.41, Cα/Hα in phenylcoumarans (Bα); 94.2/6.56, C8/H8 in tricin (T8); 98.9/6.23, C6/H6 in tricin (T6); 103.8/6.68, C2/H2 and C6/H6 in syringyl units (S2,6); 104.1/7.30, C2′,6′/H2′,6′ in tricin (T2′,6′); 104.7/7.03, C3/H3 in tricin (T3); 106.2/7.29, C2/H2 and C6/H6 in α-oxidized syringyl units (S′2,6); 110.7/6.93, C2/H2 in guaiacyl units (G2); 111.0/7.28, C2/H2 in ferulic acid (FA2); 114.0/6.40, Cβ/Hβ in p-coumaric acid (PCAβ); 114.9/6.75, C3,5/H3,5 in p-hydroxybenzoic acid (PB3,5); 115.0/6.58–7.00, C5/6/H5/6 in guaiacyl units (G5/6); 118.9/6.75, C6/H6 in guaiacyl units (G6); 123.3/7.11, C6/H6 in ferulic acid (FA6); 127.8/7.18, C2,6/H2,6 in p-hydroxyphenyl units (H2,6); 130.1/7.50, C2,6/H2,6 in p-coumaric acid (PCA2,6); 131.2/7.65, C2,6/H2,6 in p-hydroxybenzoic acid (PB2,6); and 145.2/7.56, Cα/Hα in p-coumaric acid and ferulic acid (PCAα and FAα). Additional signals (in cyan) correspond to selected correlations of carbohydrate xylose (X), including α/β reducing ends (X(R)), acetylated xylose (X′), arabinose (Ar), glucose (Gl), and uronic acid (U) units (unassigned carbohydrate signals are in gray)