by a few types of animals, such as some termites, snails, and earthworms.

Cellulases have also been found in green microalgae (Chlamydomonas reinhardtii, Gonium pectorale and Volvox carteri) and their catalytic domains (CD) belonging to GH9 Family show highest sequence homology to metazoan endogenous cellulases. Algal cellulases are modular,