Computer-aided search for a cold-active cellobiose 2-epimerase.

Area of Science:

• Biotechnology
• Enzymology
• Dairy Science

Background:

• Cellobiose 2-epimerase (CE) is valuable for converting lactose into epilactose and lactulose.
• The dairy industry requires low-temperature lactose bioconversion to prevent microbial contamination.
• Discovering cold-active enzymes is crucial for efficient, safe industrial bioprocessing.

Purpose of the Study:

• To discover and characterize a cold-active cellobiose 2-epimerase (CE) for low-temperature lactose bioconversion.
• To enable the production of high-value lactose derivatives under conditions that inhibit microbial growth.

Main Methods:

• Genome mining using computational prediction to identify potential cold-active CE genes.
• Heterologous expression of the identified CE gene in Escherichia coli.
• Biochemical characterization of the recombinant enzyme's activity, including optimal conditions and kinetic parameters.

Main Results:

• The recombinant Roseburia intestinalis CE enzyme exhibited optimal activity at 45°C and pH 7.0.
• Specific activity for lactose to epilactose conversion was 77.3 ± 1.6 U/mg.
• At 8°C, the enzyme converted 20.9% of lactose to epilactose in 4 hours, demonstrating suitability for low-temperature applications.

Conclusions:

• A novel cold-active CE enzyme was successfully identified through in silico screening and characterized.
• The enzyme is effective for low-temperature epilactose production, meeting dairy industry needs.
• This discovery facilitates efficient and safe bioconversion of lactose at reduced temperatures.