Unit 6: Applied microbiology - Practice Quiz

1 Which term describes microorganisms grown on a large scale to manufacture useful commercial products?

2 A product formed during the active growth phase and essential for growth is called a:

3 Antibiotics like penicillin are examples of which type of microbial product?

4 Penicillin, an important antibiotic for the health industry, is produced by which organism?

5 Which microbial product is widely used to treat bacterial infections in humans?

6 Vitamin is commercially produced mainly by which type of microorganisms?

7 Riboflavin, produced by microbial fermentation, is also known as which vitamin?

8 Which fungus is commonly used for the industrial production of riboflavin?

9 The microbial conversion of one steroid into another useful steroid is an example of:

10 Microbial modification of steroids is industrially important for producing which type of drugs?

11 Which microorganism is used in baking bread to make dough rise?

12 Which bacteria are mainly responsible for converting milk into yogurt?

13 The souring of milk into curd is caused by the production of which acid?

14 Biotransformation is best defined as the:

15 An advantage of using microbes for biotransformation is that reactions are:

16 Which enzyme is widely used in detergents to remove protein stains?

17 The enzyme amylase produced by microbes is used industrially to break down:

18 Which amino acid, used as a flavor enhancer (MSG), is produced industrially by microbial fermentation?

19 In alcoholic fermentation by yeast, sugar is mainly converted into ethanol and:

20 Biohydrogen is considered an attractive fuel mainly because its combustion produces:

21 A fermentation product that is synthesized during the stationary phase and is not essential for the primary growth of the microorganism is best classified as a:

22 In a batch fermentation, penicillin production by Penicillium chrysogenum is favored when growth is limited. Which strategy is most commonly used to prolong the production phase?

23 Recombinant human insulin is produced industrially using genetically engineered:

24 Streptokinase, used clinically as a thrombolytic (clot-dissolving) agent, is derived from:

25 Vitamin (cobalamin) is produced industrially almost exclusively by microbial fermentation because:

26 Riboflavin (vitamin ) is produced commercially in high yields using the fungus:

27 The microbial transformation of progesterone into 11α-hydroxyprogesterone by Rhizopus species is significant because it:

28 Which feature of microbial steroid biotransformations makes them industrially superior to purely chemical methods?

29 In yogurt production, Lactobacillus bulgaricus and Streptococcus thermophilus act synergistically. The primary chemical change responsible for milk thickening is:

30 During bread making, the leavening (rising) of dough by Saccharomyces cerevisiae is primarily due to:

31 Biotransformation differs from full de novo fermentation mainly in that biotransformation:

32 The industrial conversion of sorbitol to L-sorbose by Gluconobacter is a key step in the manufacture of:

33 Thermostable DNA polymerase (Taq polymerase) used in PCR is obtained from:

34 Which microbial enzyme is widely added to laundry detergents to remove protein-based stains such as blood and food?

35 Glucose isomerase is industrially important because it converts glucose into fructose to produce:

36 Industrial production of L-glutamic acid (for monosodium glutamate) is carried out mainly using:

37 Overproduction of an amino acid such as lysine in industrial strains is often achieved by selecting mutants that are:

38 In a continuous (chemostat) fermentation, the specific growth rate of the culture at steady state is controlled by the:

39 Citric acid is produced industrially by Aspergillus niger. High yields are favored by:

40 In dark fermentation for biohydrogen production, the highest theoretical yield of per mole of glucose is obtained when the main byproduct is:

41 In a fed-batch penicillin fermentation, glucose is fed at a controlled low rate rather than added as a single large bolus. What is the primary physiological rationale for this feeding strategy?

42 A continuous chemostat operates at steady state. If the dilution rate is increased to a value that exceeds , what outcome is expected?

43 The microbial 11-hydroxylation of progesterone by Rhizopus species was industrially significant primarily because it:

44 In industrial L-glutamate production by Corynebacterium glutamicum, biotin limitation or Tween 40 addition boosts glutamate secretion mainly by:

45 Commercial vitamin B12 (cobalamin) is produced almost exclusively by microbial fermentation rather than chemical synthesis because:

46 Glucose isomerase is used to make high-fructose corn syrup. Which property makes its immobilization particularly advantageous for continuous industrial operation?

47 A key advantage of using whole-cell biotransformation over isolated enzymes for a multi-step redox reaction requiring NAD(P)H is:

48 In dark fermentation for biohydrogen, the theoretical maximum yield when acetate is the sole end product is 4 mol H per mol glucose, yet practical yields are lower. The main biochemical reason is:

49 During cheese ripening, why is a secondary starter such as Penicillium roqueforti deliberately introduced in blue cheeses?

50 Recombinant human insulin produced in E. coli originally required separate expression of the A and B chains. A major processing challenge unique to this system compared to eukaryotic hosts was:

51 In a submerged aerobic fermentation, the volumetric oxygen transfer rate is given by . To sustain a high-density culture without oxygen limitation, which change most directly increases without altering the driving force ?

52 To overproduce L-lysine, industrial strains of C. glutamicum carry a feedback-resistant aspartokinase. Why is this modification essential?

53 Side-chain cleavage of sterols such as cholesterol to yield androstenedione (AD) using Mycobacterium mutants relies on blocking which pathway?

54 Detergent proteases (subtilisins) are engineered for improved performance. Substituting the oxidation-sensitive methionine near the active site (e.g., Met222) with a non-oxidizable residue primarily improves:

55 In the microbial synthesis of riboflavin (vitamin B2) by Ashbya gossypii, addition of excess iron to the medium tends to:

56 A secondary metabolite shows a classic trophophase–idiophase pattern. Which statement best characterizes the idiophase?

57 A biotransformation must convert a prochiral ketone to a single (S)-alcohol enantiomer at >99% ee. Why is a ketoreductase-based microbial process often preferred over chemical reduction?

58 Coupling dark fermentation with photofermentation in a two-stage biohydrogen system improves overall yield because photofermentative bacteria:

59 In sourdough fermentation, the characteristic flavor and leavening arise from a stable consortium of lactic acid bacteria and yeasts. Why do the yeasts often coexist rather than being outcompeted by the acid-producing LAB?

60 Statins such as lovastatin are produced by Aspergillus terreus as secondary metabolites. When engineering higher titers, why is precursor supply of acetyl-CoA and malonyl-CoA a critical bottleneck?