How are liquid batch cultures most often aerated to support the growth of aerobic microbes?

• A. By adding chemical oxygen generators to the medium
• B. By sealing the flask to prevent contamination
• C. By incubating the culture in complete darkness
• D. By shaking the culture flask to increase oxygen diffusion

Answer: (D)

Verified step by step guidance

1. Understand that aerobic microbes require oxygen for their metabolism and growth, so providing sufficient oxygen in the culture environment is essential.
2. Recognize that in liquid batch cultures, oxygen must be efficiently transferred from the air to the liquid medium where microbes reside.
3. Identify that shaking the culture flask increases the surface area of the liquid exposed to air and promotes mixing, which enhances oxygen diffusion into the medium.
4. Note that other options like adding chemical oxygen generators, sealing the flask, or incubating in darkness do not effectively increase oxygen availability for aerobic microbes.
5. Conclude that shaking the culture flask is the most common and practical method to aerate liquid batch cultures to support aerobic microbial growth.