Industrial production of glutamic acid MCQs With Answer

Industrial production of glutamic acid is a vital subject for B. Pharm students, combining microbial fermentation, bioprocess engineering and downstream purification. Key topics include Corynebacterium glutamicum-based fermentation, carbon and nitrogen sources, fed-batch strategies, oxygen transfer, pH and temperature control, metabolic engineering to relieve feedback inhibition, and purification methods like cell separation, ion-exchange and crystallization. Practical issues—yield and productivity (g/L·h), quality control by HPLC, stereochemistry (L‑glutamic acid), GMP requirements and cost drivers—link theory to pharmaceutical manufacturing. This focused overview helps students understand production, analytics and regulatory context. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which microorganism is most widely used for industrial glutamic acid production?

• Corynebacterium glutamicum
• Escherichia coli
• Bacillus subtilis
• Saccharomyces cerevisiae

Correct Answer: Corynebacterium glutamicum

Q2. What is the primary carbon source in most industrial glutamate fermentations?

• Glucose (simple sugar)
• Glycerol
• Lactose
• Acetate

Correct Answer: Glucose (simple sugar)

Q3. Which stereoisomer is the main product in commercial glutamic acid production?

• L‑Glutamic acid
• D‑Glutamic acid
• Racemate (DL‑glutamic acid)
• γ‑Glutamic acid

Correct Answer: L‑Glutamic acid

Q4. Which fermentation mode is most commonly used to maximize glutamate yield industrially?

• Fed‑batch fermentation
• Continuous chemostat fermentation
• Pure batch fermentation without feed
• Solid‑state fermentation

Correct Answer: Fed‑batch fermentation

Q5. Which metabolic intermediate is the direct precursor of glutamic acid in central metabolism?

• α‑Ketoglutarate (alpha‑ketoglutarate)
• Oxaloacetate
• Pyruvate
• Succinate

Correct Answer: α‑Ketoglutarate (alpha‑ketoglutarate)

Q6. Which enzyme catalyzes the reductive amination of α‑ketoglutarate to form glutamate?

• Glutamate dehydrogenase
• Glutamine synthetase
• Transketolase
• Alanine transaminase

Correct Answer: Glutamate dehydrogenase

Q7. Which nitrogen source is commonly used in industrial glutamate fermentations?

• Ammonium sulfate
• Nitrate
• Peptone only
• Complex proteins without inorganic nitrogen

Correct Answer: Ammonium sulfate

Q8. Which operational parameter most directly affects respiration and product formation in glutamate fermentation?

• Dissolved oxygen (DO)
• Light intensity
• Magnetic field
• Salinity only

Correct Answer: Dissolved oxygen (DO)

Q9. How is feedback inhibition typically overcome to increase glutamate production?

• Use of feedback‑resistant mutant strains
• Lowering fermentation temperature drastically
• Adding feedback inhibitors to the broth
• Switching to anaerobic conditions

Correct Answer: Use of feedback‑resistant mutant strains

Q10. What is the common first downstream operation to separate cells from fermentation broth?

• Centrifugation
• Distillation
• Sublimation
• Lyophilization

Correct Answer: Centrifugation

Q11. Which purification technique is frequently used to separate glutamic acid from ionic impurities?

• Ion‑exchange chromatography
• Size‑exclusion chromatography
• Gel electrophoresis
• Affinity chromatography against antibodies

Correct Answer: Ion‑exchange chromatography

Q12. How is monosodium glutamate (MSG) commonly produced from glutamic acid?

• Neutralization with sodium hydroxide to form the sodium salt
• Oxidation with potassium permanganate
• Reduction with sodium borohydride
• Carbonation with CO2

Correct Answer: Neutralization with sodium hydroxide to form the sodium salt

Q13. Which metric expresses fermentation productivity most directly?

• Volumetric productivity (g/L·h)
• Optical density (OD600) alone
• Total fermentation time only
• pH units per hour

Correct Answer: Volumetric productivity (g/L·h)

Q14. Around which pH is glutamate secretion by Corynebacterium strains typically optimized?

• Approximately pH 7.0
• pH 3.0
• pH 10.5
• pH 12.0

Correct Answer: Approximately pH 7.0

Q15. What is the typical cultivation temperature for Corynebacterium glutamicum in industrial processes?

• Around 30°C
• Above 50°C
• Below 10°C
• Around 75°C

Correct Answer: Around 30°C

Q16. What is the main purpose of a fed‑batch strategy in glutamate fermentation?

• Control substrate feeding to avoid overflow metabolism and increase yield
• Maintain zero biomass throughout the run
• Ensure complete anaerobic conditions at all times
• Enable continuous removal of product without feed

Correct Answer: Control substrate feeding to avoid overflow metabolism and increase yield

Q17. How does metabolic engineering commonly improve glutamate titers?

• Overexpressing key enzymes to increase flux toward α‑ketoglutarate and reduce competing pathways
• Removing all plasmids to avoid expression burden
• Introducing eukaryotic organelles into bacteria
• Increasing intracellular salt concentration only

Correct Answer: Overexpressing key enzymes to increase flux toward α‑ketoglutarate and reduce competing pathways

Q18. Which compound is a common undesirable byproduct under oxygen limitation in glutamate fermentation?

• Lactate
• Cholesterol
• Cellulose
• Ethylene

Correct Answer: Lactate

Q19. Which analytical technique is commonly used for quantitative determination of glutamic acid in process samples?

• High‑performance liquid chromatography (HPLC)
• Nuclear magnetic resonance imaging (MRI)
• Gas chromatography without derivatization
• Paper chromatography only

Correct Answer: High‑performance liquid chromatography (HPLC)

Q20. Which method is most suitable to confirm the L‑configuration of produced glutamic acid?

• Chiral HPLC analysis
• General UV absorbance at 280 nm
• Simple refractive index measurement
• Conductivity only

Correct Answer: Chiral HPLC analysis

Q21. What biosafety level is Corynebacterium glutamicum generally classified as for industrial use?

• BSL‑1
• BSL‑3
• BSL‑4
• BSL‑2 with viral precautions

Correct Answer: BSL‑1

Q22. Which genetic approach is commonly used to enhance glutamate production traits?

• Plasmid‑based overexpression of biosynthetic genes
• Inserting eukaryotic mitochondria
• Introducing viral coat proteins
• Reducing genome size by random deletion of essential genes

Correct Answer: Plasmid‑based overexpression of biosynthetic genes

Q23. Which downstream sequence is typical to recover crystalline glutamic acid or MSG?

• Ion‑exchange purification followed by concentration and crystallization
• Direct spray‑drying of whole broth
• Membrane fusion of cells then freeze‑dry
• Immediate lyophilization without purification

Correct Answer: Ion‑exchange purification followed by concentration and crystallization

Q24. Which parameter quantitatively describes oxygen transfer capacity of a bioreactor?

• kLa (volumetric mass transfer coefficient)
• pKa of the medium
• Heat transfer coefficient only
• Specific gravity

Correct Answer: kLa (volumetric mass transfer coefficient)

Q25. Why are antifoam agents added during glutamate fermentation?

• To suppress excessive foam that can cause contamination and operational problems
• To increase foam for better aeration
• To precipitate glutamate directly
• To act as an additional carbon source

Correct Answer: To suppress excessive foam that can cause contamination and operational problems

Q26. Why is molasses used as a feedstock in some industrial glutamate processes?

• It is a low‑cost, high‑sugar carbon source
• It contains high levels of pure amino acids already
• It sterilizes the medium automatically
• It prevents any byproduct formation entirely

Correct Answer: It is a low‑cost, high‑sugar carbon source

Q27. What unit is typically used to express product yield in fermentation process calculations?

• g product per g substrate (g/g)
• molality only
• Liters per kilogram (L/kg) unrelated to product
• Watts per square meter

Correct Answer: g product per g substrate (g/g)

Q28. Which regulatory framework is essential when producing pharmaceutical‑grade amino acids?

• Good Manufacturing Practice (GMP) compliance
• Only local food labeling laws
• International maritime law
• Traffic safety regulations

Correct Answer: Good Manufacturing Practice (GMP) compliance

Q29. Which mechanism is primarily responsible for glutamate secretion from production strains?

• Activation of specific glutamate exporters/transmembrane transport proteins
• Passive diffusion due to small size only
• Secretion via viral lysis proteins
• Extracellular polymer synthesis

Correct Answer: Activation of specific glutamate exporters/transmembrane transport proteins

Q30. What is the standard method to sterilize fermentation media before inoculation?

• Autoclaving (moist heat sterilization)
• Adding antibiotics without heat
• Exposing to visible light only
• Filtration through paper towels

Correct Answer: Autoclaving (moist heat sterilization)

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