Ligninet

Ligninet is a term used in plant science and materials research to describe the interconnected three-dimensional network formed by lignin within the plant cell wall. Lignin is a heterogeneous polyphenolic polymer derived from monolignols such as coniferyl, sinapyl and p-coumaryl alcohols; during lignification these units couple in a variety of ways to create a cross-linked matrix that imparts rigidity and chemical resilience to the wall.

The ligninet network interacts with cellulose microfibrils and hemicelluloses, contributing mechanical strength, hydrophobicity, and resistance to enzymatic and microbial attack. Its topology is influenced by species, tissue type, and developmental stage, and is characterized by a range of inter-unit linkages including β-O-4, β-β, 5-5, and β-5 bonds, among others. Because of its heterogeneity, the precise arrangement is challenging to define comprehensively.

In research and industry, ligninet is used to discuss biomass recalcitrance and strategies for deconstruction in biofuel production, pulping, and bioprocessing. Characterization relies on spectroscopic and imaging techniques such as NMR, FTIR, Raman, and solid-state imaging to probe ligninet composition and its interactions with polysaccharides. Ongoing work seeks to model ligninet structure, control its formation through plant breeding or processing, and develop materials that exploit its properties.

See also: lignin, plant cell wall, lignocellulose.