Deck 28: Applied and Industrial Microbiology

Question 1

All of the following are advantages of a bioreactor instead of a flask culture EXCEPT

A) instrumentation for monitoring environmental conditions.
B) uniform aeration and mixing.
C) larger culture volumes can be grown.
D) aseptic sampling.
E) None of the answers is correct; all of these are advantages of using a bioreactor instead of a flask culture.

Answer 1

E

Question 2

Spoilage of canned foods due to inadequate processing, NOT accompanied by gas production, is

A) thermophilic anaerobic spoilage.
B) flat sour spoilage.
C) caused by acid-tolerant fungi.
D) putrefactive anaerobic spoilage.
E) spoilage by mesophilic bacteria.

Answer 2

B

Question 3

Commercial sterilization differs from complete sterilization in that commercial sterilization

A) kills all microorganisms.
B) may result in the survival of thermophiles.
C) may result in the survival of fungal spores.
D) kills only bacteria.
E) employs a higher temperature.

Answer 3

B

Question 4

Figure 28.1

In Figure 28.1, assume the cells are producing penicillin which is collected during the idiophase. Remember, the top lines/markings indicate the different phases observed in the curve below them. When would you be able to collect the penicillin?

A) a
B) b
C) c
D) d

Question 5

All of the following are industrial products produced by microbes EXCEPT

A) vitamin B12 and riboflavin.
B) industrial enzymes.
C) amino acids in food supplements.
D) uranium.
E) antibiotics.

Question 6

Figure 28.1

In Figure 28.1, assume that a secondary metabolite is your desired product. Remember, the top lines/markings indicate the different phases observed in the curve below them. When would you be able to obtain it?

A) a
B) b
C) c
D) d

Question 7

Which of the following is an undesirable contaminant in wine-making?

A) Saccharomyces
B) lactic acid bacteria
C) Acetobacter
D) Clostridium botulinum endospores

Question 8

Spoilage of canned foods stored at high temperatures, accompanied by gas production, is

A) flat sour spoilage.
B) caused by acid-tolerant fungi.
C) putrefactive anaerobic spoilage.
D) thermophilic anaerobic spoilage.
E) spoilage by mesophilic bacteria.

Question 9

Commercial sterilization of processed canned foods uses a 12D treatment which is based upon a theoretical population of 1012 C. botulinum endospores in a can of food. After treatment, there would theoretically be how many endospores left?

A) 12 endospores
B) 10 endospores
C) 100 endospores
D) 120 endospores
E) 1 endospore

Question 10

Which of the following pairs is mismatched?

A) Acetobacter  vinegar
B) Propionibacterium  Swiss cheese
C) Lactobacillus  yogurt
D) Bacillus  beer
E) Penicillium  blue cheese

Question 11

Which of the following reactions is performed by yeast in wine-making?

A) ethanol → acetic acid
B) carbon dioxide → sucrose
C) sugar → ethanol
D) malic acid → lactic acid
E) sugar → Co₂ + H₂O

Question 12

All of the following are true of irradiation methods used for food preservation and sterilization EXCEPT

A) they prolong shelf-life of fruits and vegetables.
B) they are used for the sterilization of many spices.
C) they greatly reduce the number of pathogens present in meats and poultry.
D) residual radioactivity is left behind on many foods.
E) ionizing radiation such as X rays or gamma rays is used.

Question 13

Figure 28.1

In Figure 28.1, assume the cells are your desired product and you want to maintain a continuous culture. Remember, the top lines/markings indicate the different phases observed in the curve below them. When would you harvest cells to maximize your yield?

A) a
B) b
C) c
D) d

Question 14

A baker forgets to put yeast in his bread dough. Which of the following do you expect to happen to the bread as a result?

A) The bread will look normal but will be tough.
B) Bacterial contaminants will now be able to grow.
C) The bread will have a sour taste.
D) The bread will not rise.
E) It will take longer to bake.

Question 15

Microorganisms play an active role in the formation of industrial products. Which of the following is mismatched?

A) Saccharomyces cerevisiae  for fermentation
B) Penicillium  treatment of disease
C) Rhizobium  increases nitrogen in the soil
D) algae  citric acid
E) Bacillus thuringiensis  insecticide

Question 16

Which of the following pertains to an improperly canned food product on a store shelf that has a bad odor and putrefaction of the canned material?

A) mesophilic spoilage
B) flat sour spoilage
C) hydrogen sulfide spoilage
D) bacterial soft rot
E) thermophilic anaerobic spoilage

Question 17

Microbial products can be improved by all of the following EXCEPT

A) isolating new strains.
B) mutating existing strains.
C) sterilization.
D) genetically modifying strains.
E) modifying culture conditions.

Question 18

Which of the following reactions makes wine less acidic, and is important for good flavor when grapes with higher acidity are used?

A) carbon dioxide → sucrose
B) ethanol → acetic acid
C) sugar → Co₂ + H₂O
D) sugar → ethanol
E) malic acid → lactic acid

Question 19

All of the following are fuels produced by microorganisms EXCEPT

A) hydrogen.
B) cellulose.
C) oil from algae.
D) ethanol.
E) methane.

Question 20

Which of the following microorganisms is usually used in the fermentation of alcoholic beverages?

A) Lactobacillus
B) Saccharomyces
C) Propionobacterium
D) Rhizopus
E) Penicillium

Question 21

All of the following are uses for ionizing or ultraviolet radiation EXCEPT

A) sterilizing spices.
B) prevention of sprouting.
C) heating cold food.
D) inactivation of Trichinella larvae.
E) killing of insect eggs and larva.

Question 22

All of the following are industrial products produced using microbial fermentations EXCEPT

A) riboflavin.
B) citric acid.
C) glutamic acid.
D) aspartic acid.
E) saccharin.

Question 23

Canning works to preserve foods through

A) increasing pH.
B) creation of an anaerobic environment.
C) exposure to high heat.
D) mutation of bacterial DNA.
E) creation of an anaerobic environment and exposure to high heat.

Question 24

Aseptic packaging (where the packaging itself is rendered sterile) helps to preserve foods through

A) mutation of bacterial DNA by exposure to the packaging material.
B) creation of an anaerobic environment in the packaging.
C) exposure of the packaging to high heat.
D) increasing pH in the food contained in the packaging.
E) creation of an anaerobic environment in the packaging and exposure of the packaging to high heat.

Question 25

All of the following foods are produced using microbial fermentations EXCEPT

A) sauerkraut.
B) coffee.
C) ketchup.
D) sour cream.
E) yogurt.

Question 26

What role do lactic acid bacteria play in cheese production?

A) production of holes in Swiss cheese
B) curd formation
C) ripening the cheese
D) providing characteristic flavor and smell
E) Lactic acid bacteria carry out each of these roles in cheese production.

Question 27

Aseptic packaging utilizes which of the following to sterilize laminated paper or plastic prior to filling with food?

A) hot hydrogen peroxide solution
B) hot HCl solution
C) autoclave
D) X rays
E) gamma radiation

Question 28

Which of the following microbes produces a natural biopesticide?

A) Penicillium chryssogenum
B) Saccharomyces cerevisiae
C) Lactobacillus buggaricus
D) Bacillus thuringiensis
E) Thiobacillus ferroxidans

Question 29

Canning preserves food

A) by exposure to radiation.
B) by exposure to high pH.
C) by exposure to chemicals.
D) through use of aseptic packaging.
E) by exposure to high heat.

Question 30

You are growing Bacillus subtilis, an aerobic bacterium that can also carry out fermentation when required, in a bioreactor and notice that the growth rate has slowed and the pH has decreased. What could you add?

A) peptides
B) lactic acid
C) oxygen
D) lactose
E) glucose

Question 31

Figure 28.3

Figure 28.3 shows the growth curves of Acetobacter under different conditions. Which culture would produce the highest amount of the primary metabolite acetic acid?

A) a
B) b
C) c
D) d
E) e

Question 32

Figure 28.3

Which of the growth curves in Figure 28.3 will give the highest yield of a secondary metabolite?

A) a
B) b
C) c
D) d
E) e

Question 33

Biomass is a renewable energy source derived from the organic matter produced by living organisms. All of the following are sources of biomass EXCEPT

A) algae.
B) oxidation of metals.
C) crops.
D) landfill sites.
E) bacteria.

Question 34

Microorganisms themselves are commercial products. Which of the following microbes is available as a product sold in retail stores?

A) Saccharomyces
B) Rhizobium
C) Lactobacillus
D) Bacillus thuringiensis
E) All of these organisms can be found in various commercial products.

Question 35

Acidithiobacillus ferrooxidans is used for the recovery of from ore.

A) gold
B) sulfur
C) sulfuric acid
D) iron
E) copper

Question 36

You are growing Bacillus subtilis, an aerobic bacterium that can also carry out fermentation when required, in a bioreactor and notice that the growth rate has slowed and the pH has decreased. You suspect the bacteria are

A) fermenting.
B) using proteins.
C) photosynthesizing.
D) using the Krebs cycle.
E) dead.

Question 37

As cheese ages, it gets

A) saltier.
B) more alcoholic.
C) more acidic.
D) more protein.
E) more whey.

Question 38

What process does yeast use to produce ethanol for automobile fuel from corn?

A) fermentation
B) the Krebs cycle
C) oxidation
D) photosynthesis
E) anaerobic respiration

Question 39

The following steps are required for making cheese. What is the second step, which helps to provide the characteristic flavors and aromas of the cheese?

A) enzymatic coagulation of milk
B) separation of curds and whey
C) inoculation with lactic acid bacteria
D) inoculation with Penicillium
E) fermentation of curd

Question 40

All of the following are industrial enzymes made by microbial fermentations EXCEPT

A) rennin.
B) proteases.
C) amylases.
D) vitamin C.
E) glucose isomerase.

Question 41

All of the following are reasons for utilizing algae for biofuel production EXCEPT

A) they produce more energy per acre than corn.
B) they produce a nondegradable waste product.
C) they can utilize agriculturally poor land.
D) their main requirement is abundant light.
E) they do not take up land needed for food production.

Question 42

Vessels used for industrial fermentation reactions are known as bioreactors. Explain the difference between batch production and continuous flow production using a bioreactor.

Question 43

Rhizobium and Bradyrhizobium are mixed with peat moss to increase nitrogen fixation.

Question 44

The blue-green clumps observed in Roquefort cheese are a result of mold growth.

Question 45

Discuss the production of four different foods that require microbial fermentation in their products. In your discussion, name the specific microorganisms used and describe the fermentation by-product(s) needed for the production of each food item.

Question 46

Xanthan used in household products is produced by bacteria

A) selected for their ability to utilize lactose rather than glucose and that are plant pathogens.
B) that are plant pathogens.
C) that were irradiated to mutate them.
D) selected for their ability to utilize lactose rather than glucose.
E) that were genetically modified.

Question 47

High-pressure processing of foods such as deli meats and precooked chicken strips targets pathogens such as Salmonella and Listeria.

Question 48

Explain how ionizing radiation can be used to preserve foods. Discuss its advantage over canning as a method of preservation.

Question 49

The production of vinegar relies on the microbial oxidation of ethanol to acetic acid.

Question 50

A large industry exists based on the synthesis of amino acids by microorganisms.

Question 51

If an industrial microbiologist works with Acidithiobacillus ferrooxidans, he is likely to be involved in copper mining.

Question 52

Vitamins A and E are commonly produced by microorganisms.)

Question 53

Industrial canning, as opposed to home canning, is achieved using a pressure cooker which operates in a manner similar to an autoclave.

Question 54

Bioreactors are widely used for industrial fermentation. Which of the following conditions must be closely monitored for optimal fermentation?

A) oxygen levels
B) temperature
C) pH
D) both temperature and pH
E) temperature, pH, and oxygen levels

Question 55

What will be produced if wine is aerated and inoculated with bacteria of the genera Acetobacter and Gluconobacter?

A) Co₂ + H₂O
B) acetic acid
C) CH4
D) ethanol + Co₂
E) None of the answers is correct.

Question 56

Discuss the production of three different non-food/beverage substances that utilize microorganisms in their production. Your discussion should include the specific microorganisms involved and their role in the production of each substance.

Question 57

The longer interior-ripened cheeses are permitted to ripen, the milder the taste of the cheese.

Question 58

Radiation works to preserve foods through

A) exposure to high heat.
B) lethal mutation of bacterial DNA.
C) increasing pH.
D) creation of an anaerobic environment and high heat.
E) creation of an anaerobic environment.

Question 59

Mesophilic bacteria grow best at temperatures of 60°C.