Fermentation Technology Questions and Answers – Yeast Condition and Surplus Yeast

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This set of Fermentation Technology Multiple Choice Questions & Answers (MCQs) focuses on “Yeast Condition and Surplus Yeast”.

1. Which of the following is not the type of quality test of yeast?
a) Determining microbial contamination in yeast
b) Determining the phenotype of yeast
c) Determine the physiological condition of yeast
d) Determining the viability of yeast
View Answer

Answer: b
Explanation: There are three types of test to access the condition of yeast. First, the yeast must be free from microbial contamination. Testing the microbiological condition of yeast is important. Second, it is important to determine the viability of the yeast. Third, vitality tests to determine the physiological condition of the yeast.
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2. Which of the following method is procedure is used to access the yeast viability in the brewing industry?
a) Methylene blue test
b) Phenolphthalein test
c) Safranin test
d) Coombs test
View Answer

Answer: a
Explanation: Methylene blue test is the most common procedure to access the viability of yeast in the brewing industry. In this test, the viable cells remain colourless whereas the dead cells are stained blue. Crystal violet, aniline blue, etc. are also used for accessing the yeast condition.

3. Which of the following is used to count the number of cells?
a) Haemoglobinometer
b) Haemocytometer
c) Spectrophotometer
d) Flowcytometry
View Answer

Answer: b
Explanation: Haemocytometer is used to count the number of cells. It is a counting chamber device that is usually used to count the number of red blood cells, white blood cells, spore counting, etc.

4. Who compared the efficacy of viability measurement by different methods?
a) Smart
b) Sami
c) Nomura
d) Nishikawa
View Answer

Answer: a
Explanation: Smart et al. in 1999 compared the efficacy of viability measurement by plate counts, methylene blue/safranin O double staining, citrate methylene blue, alkaline methylene blue, citrate methylene violet and alkaline methylene violet. Ale, lager, cider yeast in various physiological condition were used in the assessment.

5. Which of the following method is not reliable for viability tests?
a) Plate counts
b) Methylene blue/Safranin O double stain
c) Alkaline methylene violet test
d) Citrate methylene violet
View Answer

Answer: b
Explanation: Methylene blue/Safranin O double stain failed to distinguish between viable and non-viable cells. Therefore, it is not a reliable method for accessing the yeast condition, particularly in the exponential phase of the growth.
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6. Which of the following gets accumulated in viable cells?
a) Rhodamine 123
b) Acridine Orange
c) Ozonol dye
d) Mg-ANS
View Answer

Answer: d
Explanation: Mg 1-anilino-8-naphthalene sulphonic acid (Mg-ANS) gets accumulated in the viable cells with the functional membrane and binds to the proteins. It was reported by King et al. in 1981 and McCaig in 1990.

7. Which of the following is excluded by viable cells?
a) Propidium iodide
b) Rhodamine 123
c) Acridine dye
d) Mg-ANS
View Answer

Answer: a
Explanation: Propidium iodide is excluded by the viable cells whereas, in non-viable cells, it binds to the nucleic acids present inside the nucleus of the cell. It was reported by Bank in 1988 and Hutter in 1993.

8. Which of the following is not a characteristic of the viable cell?
a) The capability of cellular growth
b) The capability of cellular proliferation
c) Oxygen evolution and carbon-dioxide uptake
d) Possession of membrane integrity
View Answer

Answer: c
Explanation: The characteristics of viable cells include the capability of cellular growth (progression through cell cycle), the capability of cellular growth (anabolic metabolism), detectable resting metabolism (oxygen uptake and carbon-dioxide evolution), and the possession of membrane integrity (excretion of by-products).

9. Which of the following provides the energy for sterol synthesis?
a) Glycogen
b) Starch
c) Mannose
d) Oxygen
View Answer

Answer: a
Explanation: Glycogen is reported to provide the energy and carbon for the synthesis of sterol during the early aerobic phase of fermentation. The yeast which has been stored for a long time cannot efficiently couple oxygen utilization for the synthesis of sterol.
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10. The glycogen content of the yeast can be determined by _________
a) Safranin
b) Phenolphthalein
c) Iodine
d) Acridine orange
View Answer

Answer: c
Explanation: The glycogen content in the yeast can be determined by using the colour reaction with iodine either qualitatively by visual assessment or quantitatively by measurement of brown colouration at 660 nm.

11. Which of the following has been useful to determine the condition of yeast?
a) Trehalose
b) Glucose
c) Lactose
d) Fructose
View Answer

Answer: a
Explanation: The levels of trehalose has been proposed as a useful monitor to determine the condition of yeast. Majara et al. in 1996 observed a positive correlation between trehalose concentration and applied stress.

12. The ATP levels in the yeast cells can be monitored using ________________
a) Chemiluminescence
b) Bioluminescence
c) Photoluminescence
d) Electroluminescence
View Answer

Answer: b
Explanation: The levels of ATP in the yeast cells can be monitored using bioluminescence, which is the emission and production of light by living organism. It occurs in many microorganisms like bacteria, fungi (yeast), as well as marine vertebrates and invertebrates.

13. Chitin can be detected by primulin.
a) True
b) False
View Answer

Answer: a
Explanation: Primulin and Calcofluor can be used in the detection of chitin which is present in the cell of fungi like yeasts and also in the exoskeleton of a few insects. The extent of staining reflects the age of the cell.
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14. All the breweries generate a surplus of yeast.
a) True
b) False
View Answer

Answer: a
Explanation: The amount of yeast remaining after the requirements of the fermentations have been met is called surplus yeast. All the breweries generate the surplus of yeast, which should be disposed to gain financially.

Sanfoundry Global Education & Learning Series – Fermentation Technology.

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn