Figure 2.
Various common bonding and linkage schemes in lignin. The figure demonstrates (A) three major phenylpropane units in lignin structure; and (B) the various types of C–O ether bonds and C–C bonds between aromatic monomer units of lignin. The figure is reproduced, without change, from Abdelaziz et al. (2016). The article is supported under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).