Cellulolytic Enzyme Systems in Invertebrate Digestion

Invertebrates employ a wide array of cellulolytic enzyme systems to access the energy stored in plant biomass. These systems combine endogenous enzymes produced by the host with complementary activities from gut symbionts, spanning bacteria, fungi and archaea. Key components include endoglucanases, exoglucanases and accessory enzymes such as lytic polysaccharide monooxygenases, which act in concert to deconstruct cellulose microfibrils and associated hemicelluloses. Some marine and terrestrial taxa also exploit non‐classical proteins—for example respiratory hemocyanins—that modify lignin or boost polymer accessibility. The diversity and specificity of these enzymes reflect adaptations to different diets and ecological niches, from wood‐boring crustaceans and detritivorous earthworms to phytophagous beetles and termites. Understanding these systems illuminates global carbon cycling and informs biotechnological applications in biofuel production, waste valorisation and environmentally targeted pest control.

Research from Nature Portfolio

Recent studies have revealed that hemocyanin plays a non‐traditional auxiliary role in wood‐boring crustaceans, enhancing lignocellulose accessibility to endogenous cellulases and modifying lignin to facilitate degradation. Biochemical assays demonstrated that the respiratory protein accumulates in the hindgut, where it interacts with plant polymers. Structural analysis suggests that haem‐iron redox activity may generate reactive oxygen species to partially disrupt lignin networks. This dual partnership between a non‐catalytic protein and classical glycoside hydrolases broadens the known repertoire of invertebrate lignocellulose‐degrading systems and offers a novel paradigm for biorefining pretreatment strategies.

Cellulolytic Enzyme Systems in Invertebrate Digestion publication trend

The graph below shows the total number of articles in cellulolytic enzyme systems in invertebrate digestion across all publications each year (not limited to Nature Index journals).

Technical terms

Lignocellulose: A composite of cellulose, hemicellulose and lignin forming plant cell walls, resistant to enzymatic attack.

Cellulase: A collective term for enzymes that hydrolyse β-1,4 bonds in cellulose, including endo- and exo-acting activities.

Glycoside hydrolase (GH) family: A classification of enzymes that catalyse the hydrolysis of glycosidic bonds, grouped by sequence and structural similarity.

Endoglucanase: A type of cellulase that cleaves internal β-1,4 links within cellulose chains, generating soluble oligosaccharides.

References

1. Trophic Position of the White Worm (Enchytraeus albidus) in the Context of Digestive Enzyme Genes Revealed by Transcriptomics Analysis. International Journal of Molecular Sciences (2024).
2. Characterization of bacterial diversity and screening of cellulose-degrading bacteria in the gut system of Glenea cantor (Fabricius) larvae. Frontiers in Bioengineering and Biotechnology (2024).
3. Diversity and Screening of Cellulolytic Microorganisms from Mangrove Forests, Natural Parks, Paddy Field, and Sugarcane Plantation in Panay Island, Philippines. International Journal of Microbiology (2024).
4. Hemocyanin facilitates lignocellulose digestion by wood-boring marine crustaceans. Nature Communications (2018).