For industrial glucose isomerization (conversion of glucose to fructose) using an immobilized enzyme such as glucose isomerase, which reactor configuration is generally preferred?

Introduction:
High-fructose syrup production relies on immobilized glucose isomerase. Reactor choice affects space-time yield, pressure drop, enzyme lifetime, and ease of operation. The typical industrial standard has evolved around configurations that minimize enzyme loss while ensuring predictable residence times.

Given Data / Assumptions:

• Enzyme is immobilized on a solid support in particulate form.
• Substrate is an aqueous glucose solution with controlled pH and metal cofactors.
• Process requires continuous, steady conversion with minimal enzyme leaching.

Concept / Approach:
Packed bed reactors hold immobilized catalyst as a fixed bed through which substrate flows, providing near plug-flow hydrodynamics and high catalyst density. This maximizes conversion per unit volume and simplifies enzyme containment, regenerations, and thermal control. Temperature and cofactor stabilization can extend enzyme life significantly in packed beds.

Step-by-Step Solution:

Verification / Alternative check:
Pilot and industrial installations consistently use fixed or packed beds. Measured pressure drops and conversions match design correlations for plug-flow approximations in such systems.

Why Other Options Are Wrong:

• CSTR: Broad residence time distribution and potential for enzyme carryover.
• Plug flow (empty tube): Enzyme must be immobilized somewhere; practically this is realized as a packed bed.
• Fluidized bed: Useful for some catalysts but risks particle attrition and enzyme loss for fragile biocatalysts.

Common Pitfalls:
Channeling due to poor packing or fines can reduce conversion. Temperature gradients can shorten enzyme lifetime; use proper thermal management and prefiltration.

Final Answer:
packed bed