Products Released from Structurally Different Dextrans by Bacterial and Fungal Dextranases

Area of Science:

• Enzymology
• Carbohydrate Chemistry
• Biotechnology

Background:

• Dextranases are crucial for dextran hydrolysis in industry and medicine.
• Dextranases from different sources exhibit varying properties, impacting their applications.
• Understanding enzyme specificity is key for structural analysis of dextrans.

Purpose of the Study:

• To comparatively analyze product patterns from linear and branched dextrans incubated with different dextranases.
• To investigate the influence of enzyme source and structure on hydrolysis outcomes.
• To explore the potential for tailoring dextran hydrolysis products through enzyme selection.

Main Methods:

• Cloning and heterologous expression of dextranase genes from *Bacteroides thetaiotaomicron* and *Streptococcus salivarius* in *Escherichia coli*.
• Hydrolysis of linear, O3-branched, and O4-branched dextrans using recombinant and commercial dextranases (*Chaetomium* sp., *Penicillium* sp.).
• Detailed analysis of hydrolysis products using High-Performance Anion-Exchange Chromatography with Pulsed Amperometric Detection (HPAEC-PAD).

Main Results:

• Bacterial and fungal dextranases produced distinct oligosaccharide profiles from branched dextrans.
• Isomaltose was a common end product from linear dextrans with most enzymes.
• *Penicillium* sp. dextranase yielded isomaltose and isomaltotetraose from linear dextrans and catalyzed disproportionation with isomaltotriose.

Conclusions:

• Enzyme source significantly influences dextran hydrolysis product patterns, especially for branched dextrans.
• Product profiles can be precisely controlled by selecting specific dextranases and managing their activity.
• This offers potential for optimized dextran structural analysis and biotechnological applications.