Culture modes: what do we call a culture grown in a closed vessel where no fresh medium is added and no wastes are removed during the run?

Introduction / Context:
Bioprocess operations are often categorized by how medium and biomass are exchanged during cultivation. This question focuses on the classic closed-system operation with no inflow or outflow during the main growth phase.

Given Data / Assumptions:

• A single charge of medium is inoculated.
• No feed or bleed occurs during cultivation (aside from sampling).
• Metabolites accumulate and nutrients deplete over time.

Concept / Approach:
In a batch culture, the system is closed: biomass, substrate, and product trajectories follow characteristic phases (lag, exponential, stationary, death). This is distinct from continuous (chemostat) and fed-batch (intermittent or continuous feeding without effluent) modes.

Step-by-Step Solution:
1) Match definition: “no addition of fresh medium and no removal of wastes” → closed system.2) Closed system in bioprocessing terminology is “batch culture.”3) Therefore select “Batch culture.”

Verification / Alternative check:
Standard kinetics models (Monod) are often fitted to batch data showing substrate depletion and product accumulation, reinforcing the closed nature of the operation.

Why Other Options Are Wrong:
Continuous includes balanced inflow/outflow; fed-batch adds medium but removes none; semi-continuous involves periodic harvest/refill; perfusion continuously removes waste/products while retaining cells.

Common Pitfalls:
Confusing fed-batch with batch because effluent is not removed; the key is that fed-batch still adds fresh medium.

Final Answer:
Batch culture