Question

The pores of filter for filtration should be between in diameter is _________

(a) 0.1 – 0.55 μm

(b) 0.2 – 0.45 μm

(c) 0.3 – 0.45 μm

(d) 0.3 – 0.50 μm

This question was posed to me in an online interview.

Asked question is from Sterilisation in section Reactor Engineering of Bioprocess Engineering

Answer 1

The correct answer is:

(b) 0.2 – 0.45 μm

Explanation: In sterilization processes, particularly when using filters for microbial removal, the pores of the filter must be small enough to retain microorganisms, which generally range in size from about 0.2 μm to several microns. For sterilization, 0.2 – 0.45 μm is the typical range of pore size used in sterilizing filters to effectively remove bacteria, fungi, and other microorganisms from liquids or gases while allowing the passage of fluids.

Filters with this pore size are widely used in the sterilization of liquids like culture media and air in bioreactors to prevent microbial contamination without compromising the flow rate.

• 0.1 – 0.55 μm and the other options are outside of the standard range commonly used for sterilization filtration.