Chitosanases are produced by a variety of microorganisms and also by some plants. Studies from the past decades concluded that the production of most bacterial
chitosanases is inducible by the presence of chitosan (87).
In addition, their involvement in the degradation and utilization of exogenous chitosan is now well documented
(88). Unlike bacterial chitosanases, most of fungal chitosanases are produced in the absence of chitosan.
Although the role of fungal chitosanases remains unclear, it seems that they are involved in cell wall metabolism and differentiation (88).
So far, a number of chitosanases genes have been sequenced. The primary structures of the respective protein have been deduced from DNA sequences of their genes. The majority of chitosanases come from Gram-positive microorganisms.The sequenced chitosanases belong to seven glycoside hydrolase families: GH3, GH5, GH7, GH8, GH46, GH75 and GH80.
The diversity of chitosanases is also reflected in the variety of their three-dimensional structures. From a mechanistic point of view, chitosanases are members of the glycoside hydrolases
and thus operate under one of the two main types of hydrolysis mechanism.
The table below summarizes the properties of the seven glycosides hydrolases families that include chitosanases members.