Immobilized enzymes prepared by microencapsulation (enzymes enclosed within semi-permeable microcapsules) provide which characteristic with respect to interfacial area?

Introduction:
Microencapsulation encloses enzymes or cells within semi-permeable membranes or microcapsules, allowing substrates and products to diffuse while retaining the biocatalyst. The particle size distribution and thin membrane walls confer transport advantages that impact reaction rates and mass transfer coefficients.

Given Data / Assumptions:

• Microcapsules are typically micrometer to sub-millimeter in size.
• Thin walls and high particle counts increase interfacial area per reactor volume.
• Diffusion through the membrane is designed to be rapid relative to reaction rates.

Concept / Approach:
Large specific surface area (area per unit volume) enhances mass transfer between bulk liquid and the immobilized phase. Numerous small capsules drastically increase contact area compared with a few large beads or bulk gels, improving substrate access and product removal. This helps reduce external mass transfer limitations in well-agitated systems.

Step-by-Step Solution:

Verification / Alternative check:
Mass transfer models show kLa improvements with increased interfacial area. Experimental uptake curves for small capsules exhibit shorter diffusion times compared with large beads.

Why Other Options Are Wrong:

• Smaller or relatively smaller surface area: Opposite of microencapsulation's key advantage.
• High amount of solvent: Not an intrinsic benefit; solvent volume depends on formulation.

Common Pitfalls:
Fragile capsules may rupture under high shear. Membrane fouling can reduce effective area over time; operating windows must be validated.

Final Answer:
an extremely large surface area