Bacterial kinetics — Under optimal laboratory conditions, the typical generation time (doubling time) of <em>Escherichia coli</em> is approximately…

Introduction / Context:
Generation time is the period required for a microbial population to double in number. It is a key parameter for growth modeling, fermentation scale-up, and understanding infection dynamics. Escherichia coli is a benchmark organism used to illustrate rapid bacterial growth under favorable conditions.

Given Data / Assumptions:

• “Optimal conditions” imply rich medium, ideal temperature, and adequate aeration.
• We compare realistic laboratory doubling times with implausibly long periods.
• Values represent orders of magnitude differences.

Concept / Approach:
In nutrient-rich media at about 37°C with sufficient oxygen, E. coli can double roughly every 20 minutes. Environmental stresses, nutrient limitation, or suboptimal temperatures increase doubling time substantially, but the canonical textbook value remains about 20 minutes for rapid laboratory growth.

Step-by-Step Solution:

Verification / Alternative check:
Growth curves plotting optical density vs. time in log phase yield slopes consistent with 3 doublings per hour, matching approximately 20 minutes per generation.

Why Other Options Are Wrong:

• 20 hours / 200 hours / 20 days: orders of magnitude too slow for E. coli in lab conditions.

Common Pitfalls:
Using environmental or clinical samples to infer doubling times; stresses there slow growth and are not representative of laboratory maxima.

Final Answer:
20 minutes