Structural basis of lignocellulose deconstruction by the wood-feeding anobiid beetle Nicobium hirtum

Abstract The details of the lignocellulose deconstruction processes in digestive systems wood-feeding insects remain elusive. This study aimed to examine biochemical conversion system a anobiid beetle, Nicobium hirtum, one most important pests wooden products Japan. To this end, N. hirtum larvae were fed with Japanese red pine (softwood) and beech (hardwood) sapwood diets, as well an artificial diet containing Shorea wood sawdust. structural differences between original digested (feces) samples examined using wet-chemical two-dimensional (2D) nuclear magnetic resonance (NMR) methods. Cellulose hemicelluloses, especially mannan softwood diet, preferentially degraded over lignin larval system. As result, was enriched residues. Lignin compositional analyses based on thioacidolysis 2D NMR determined that proportions oxidized aromatic units notably increased after digestion. Further, revealed accumulation aldehyde hydroxypropiovanillone/syringone end-unit structures lignin, indicating oxidative and/or reductive modifications polymers occur Such alterations may facilitate dissociation barrier, thereby liberating polysaccharides for subsequent enzymatic assimilation energy.