Agricultural/Bioengineering Bioprocess Engineering 3

Question 1

Which enzyme immobilization method traps enzymes within a polymer network (such as calcium alginate beads), allowing substrates and products to diffuse freely?

Accepted Answer

Gel entrapment

Answer

Covalent binding to a solid support

Answer

Cross-linking with bifunctional agents

Answer

Adsorption onto ion-exchange resin

Question 2

According to the Monod equation μ = μmax × S / (Ks + S), when substrate concentration S is much greater than Ks, the specific growth rate μ approaches:

Accepted Answer

μmax

Answer

Zero

Answer

Ks

Answer

S divided by Ks

Question 3

In a membrane bioreactor (MBR) used for wastewater treatment, what is the primary role of the membrane module?

Accepted Answer

To physically retain biomass while allowing clarified effluent to permeate

Answer

To provide a submerged surface for biofilm attachment and growth

Answer

To sterilize the incoming wastewater feed

Answer

To enhance aeration by supplying oxygen through the membrane

Question 4

Which microorganism is most commonly used for commercial-scale lactic acid production through homolactic fermentation?

Accepted Answer

Lactobacillus delbrueckii

Answer

Aspergillus oryzae

Answer

Penicillium chrysogenum

Answer

Clostridium acetobutylicum

Question 5

In thermal sterilization of fermentation media, the Del factor (∇) is used to quantify sterilization efficacy. What does ∇ represent mathematically?

Accepted Answer

Natural logarithm of the ratio of initial spore count to final spore count

Answer

Temperature gradient across the heat exchanger wall

Answer

Ratio of heat input to total culture volume

Answer

Thermal conductivity coefficient of the medium

Question 6

In ultrafiltration for bioseparation, the Molecular Weight Cut-Off (MWCO) of a membrane is defined as the molecular weight at which:

Accepted Answer

90% of solute molecules are retained by the membrane

Answer

50% of solute molecules are retained by the membrane

Answer

100% of solute molecules are retained by the membrane

Answer

The membrane pressure drop becomes unacceptable

Question 7

Which of the following fermentation products is produced under strictly anaerobic conditions to achieve maximum yield?

Accepted Answer

Bioethanol

Answer

Citric acid

Answer

Penicillin

Answer

Monosodium glutamate (MSG)