By definition, cellulase is an enzyme capable of degrading cellulose. This degradation is done by hydrolysis. In plant culture, cellulases are used to degrade the cell wall and obtain protoplasts.

Cellulases are synthesized by certain microorganisms (bacteria, fungi, protozoa) often living in symbiosis with phytophagous animals, and by certain phytophagous animals (certain insects, molluscs and annelids).

Cellulases are a group of enzymes whose main ones used for plant culture are: Onozuka R-10 cellulase and Onozuka RS cellulase.

Onozuka R-10 cellulase, also known as R-10 cellulase, is isolated from Trichoderma Viride. R-10 cellulase is a multi-enzymatic system composed of various enzymes, including cellulase, hemicellulase, pectinase and protease. R-10 cellulase is generally used in combination with R-10 macerozyme in the decomposition of plant cell walls to produce protoplasts.

Onozuka RS cellulase is produced by a mutant of Trichoderma viride derived from the parent strain of cellulase'Onozuka -R-10'. RS cellulase contains a very high activity of decomposition of natural celluloses. This type of cellulase can be used to obtain protoplasts in a very short time and dissolves the cell walls of a wider variety of plants.