Question

Choose the statements that are correct with respect to continuous culture systems:
(A) In a simple stirred tank bioreactor, stirring happens through sparging of air bubbles
(B) A bioreactor has an agitator system, oxygen delivery system, and foam control system
(C) Sampling ports provide vents to withdraw small volumes of culture periodically
(D) Culturing in bioreactors is classified as downstream processing
Choose the correct answer from the options given below:

• A. (A), (B) and (C) only
• B. (A), (C) and (D) only
• C. (B) and (C) only
• D. (A) and (D) only

Answer 1

The Correct Option is A

Let's evaluate each statement with respect to continuous culture systems:

(A) In a simple stirred tank bioreactor, stirring happens through sparging of air bubbles: This is correct. In a stirred tank bioreactor, sparging refers to the introduction of air (or other gases) into the culture, which not only provides oxygen but also helps in stirring the culture by creating bubbles. This facilitates mixing and aeration.

(B) A bioreactor has an agitator system, oxygen delivery system, and foam control system: This is correct. Bioreactors typically have an agitator system (for mixing), an oxygen delivery system (for providing oxygen to microbes or cells), and a foam control system (to manage foam formation during fermentation or culture).

(C) Sampling ports provide vents to withdraw small volumes of culture periodically: This is correct. Sampling ports are used in bioreactors to withdraw small volumes of culture for analysis or monitoring. This is important for maintaining the desired conditions and for assessing the culture's growth.

(D) Culturing in bioreactors is classified as downstream processing: This is incorrect. Downstream processing refers to the processes that occur after the culture phase, such as harvesting, purification, and product recovery. Culturing in bioreactors is part of the upstream processing phase, which involves growing cells or microorganisms and producing the target product.

Thus, the correct answer is (1) (A), (B), and (C) only.

Answer 2

Statements (A), (B), and (C) are correct. In simple stirred tank bioreactors, air sparging aids stirring; bioreactors have agitators, oxygen delivery, and foam control systems; sampling ports enable periodic culture withdrawals. Statement (D) is incorrect, as downstream processing involves product purification, while bioreactor culturing is upstream.