Enzymatic membrane reactor in xylose bioconversion with simultaneous cofactor regeneration

Area of Science:

• Biocatalysis
• Biotechnology
• Membrane Science

Background:

• Xylose bioconversion to xylonic acid is crucial for various industries.
• Efficient cofactor regeneration remains a challenge in enzymatic processes.
• Simultaneous product separation and biocatalysis can improve process economics.

Purpose of the Study:

• To co-immobilize xylose dehydrogenase and alcohol dehydrogenase from Saccharomyces cerevisiae on a nanofiltration membrane.
• To develop a biocatalytic system for efficient xylose bioconversion to xylonic acid with simultaneous cofactor regeneration and product separation.
• To evaluate the stability and reusability of the co-immobilized enzymes.

Main Methods:

• Co-immobilization of xylose dehydrogenase and alcohol dehydrogenase onto an XN45 nanofiltration membrane.
• Optimization of reaction conditions including substrate concentration, cofactor ratio, and reaction time.
• Assessment of xylonic acid production efficiency, enzyme stability, and reusability over multiple cycles and storage periods.

Main Results:

• Achieved 99% xylonic acid production efficiency under optimal conditions (5 mM xylose, 5 mM formaldehyde, NAD+:NADH ratio 1:1, 60 min).
• Demonstrated improved stability and reusability of co-immobilized enzymes.
• Maintained over 90% efficiency in six consecutive cycles and after 7 days of storage at 4°C.

Conclusions:

• Co-immobilization of enzymes on nanofiltration membranes is effective for xylose bioconversion.
• The developed biocatalytic system enables efficient xylonic acid production and cofactor regeneration.
• The system shows significant potential for industrial applications due to enhanced stability and reusability.