Production, purification, and characterization of an extracellular chitosanase from Streptomyces

Area of Science:

• Microbiology
• Enzymology
• Biochemistry

Background:

• Chitosanase enzymes are crucial for degrading chitosan, a polymer of glucosamine.
• Understanding chitosanase activity is important for applications in biotechnology and agriculture.

Purpose of the Study:

• To characterize a novel extracellular chitosanase synthesized by Streptomyces sp. no. 6.
• To investigate the enzyme's substrate specificity, optimal conditions, and biological activity.

Main Methods:

• Enzyme purification using Sephadex G-100 and ion-exchange chromatography.
• Enzyme activity assays, including substrate specificity tests and product analysis via paper chromatography.
• Determination of molecular weight, optimal pH and temperature, and kinetic parameters (Km).
• Assessment of antifungal activity against Mucor strains.

Main Results:

• The purified chitosanase hydrolyzed chitosan but not chitin or carboxymethyl-cellulose, yielding di- and triglucosamine.
• Optimal activity was observed at pH 4.5-6.5 and 60°C, with a Km of 0.688 g/liter at pH 5.5.
• The enzyme exhibited significant inhibition of Mucor spore germination and caused cell wall lysis.

Conclusions:

• Streptomyces sp. no. 6 produces an effective chitosanase with specific hydrolytic activity.
• The enzyme's properties suggest potential applications in controlling fungal growth and in chitosan biodegradation.