Bioprocess Engineering Flashcards
7 cards from real Agricultural/Bioengineering practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Bioprocess Engineering flashcards as text
Which enzyme immobilization method traps enzymes within a polymer network (such as calcium alginate beads), allowing substrates and products to diffuse freely?
Answer: Gel entrapment
Gel entrapment physically encloses enzymes within a porous polymer matrix; the enzyme cannot escape, but small substrate and product molecules diffuse in and out to sustain catalysis.
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:
Answer: μmax
When S >> Ks, the term S/(Ks + S) approaches 1, so μ approaches μmax — the organism grows at its maximum specific rate independent of further substrate increases.
In a membrane bioreactor (MBR) used for wastewater treatment, what is the primary role of the membrane module?
Answer: To physically retain biomass while allowing clarified effluent to permeate
The membrane in an MBR acts as a physical barrier that holds back suspended solids and microorganisms while allowing treated water to pass through, replacing the secondary clarifier in conventional activated sludge systems.
Which microorganism is most commonly used for commercial-scale lactic acid production through homolactic fermentation?
Answer: Lactobacillus delbrueckii
Lactobacillus delbrueckii and related homofermentative lactobacilli convert glucose almost exclusively to lactic acid via the Embden-Meyerhof-Parnas pathway, achieving high yields under anaerobic conditions.
In thermal sterilization of fermentation media, the Del factor (∇) is used to quantify sterilization efficacy. What does ∇ represent mathematically?
Answer: Natural logarithm of the ratio of initial spore count to final spore count
The Del factor ∇ = ln(N₀/N) expresses the log reduction in viable spores; a ∇ of 12 means reducing contamination probability to 10⁻¹² — one chance in a trillion batches.
In ultrafiltration for bioseparation, the Molecular Weight Cut-Off (MWCO) of a membrane is defined as the molecular weight at which:
Answer: 90% of solute molecules are retained by the membrane
MWCO is the molecular weight at which 90% of the solute is rejected by the membrane; it is the industry-standard definition used to select membranes for protein or biomolecule separations.
Which of the following fermentation products is produced under strictly anaerobic conditions to achieve maximum yield?
Answer: Bioethanol
Yeast fermentation of sugars to ethanol requires anaerobic conditions; the presence of oxygen triggers aerobic respiration (Pasteur effect), diverting carbon away from ethanol and reducing yield.