Advance in chitosan hydrolysis by non-specific cellulases

Area of Science:

• Biochemistry
• Enzymology
• Microbiology

Background:

• Chitosan, a polysaccharide derived from chitin, can be hydrolyzed by specific enzymes like chitinase and chitosanase.
• Non-specific enzymes, particularly cellulases from various microorganisms, demonstrate significant activity in degrading chitosan into chitooligomers.

Purpose of the Study:

• To investigate the role and characteristics of non-specific enzymes, especially cellulases, in chitosan hydrolysis.
• To identify and classify bifunctional enzymes exhibiting both cellulase and chitosanase activity.
• To provide a foundation for future research on the structure-function relationship of chitosanolytic cellulases.

Main Methods:

• Analysis of amino acid sequences to determine the homogeneity and classification of bifunctional cellulase-chitosanases.
• Review of existing literature on enzyme activity towards chitosan.

Main Results:

• Cellulases from diverse microbial sources effectively degrade chitosan into chitooligomers.
• Bifunctional enzymes with cellulase and chitosanase activity are identified, predominantly belonging to glycoside hydrolase family 8 (GH-8), with some in GH-5 and GH-7.
• The three-dimensional structures of these bifunctional enzymes remain largely undetermined.

Conclusions:

• Cellulases represent a significant class of enzymes capable of chitosan hydrolysis.
• The discovery of bifunctional cellulase-chitosanases, particularly within GH-8, highlights enzymatic versatility.
• Further structural elucidation of these enzymes is crucial for understanding their function in chitosan degradation.