Production of amyloglucosidase MCQs With Answer

Introduction:

This quiz set focuses on the production of amyloglucosidase (glucoamylase) — a key industrial enzyme used for starch saccharification — tailored for M.Pharm students studying Advanced Pharmaceutical Biotechnology. Questions cover microbial sources, fermentation strategies (submerged vs solid-state), medium composition and inducers, process parameters (pH, temperature, aeration), downstream processing, enzyme assays, biochemical properties (stability, metal ion effects, glycosylation), immobilization and scale-up, genetic regulation and expression strategies, and industrial applications. The items are designed to test both practical process knowledge and theoretical understanding necessary for designing, optimizing and characterizing amyloglucosidase production for pharmaceutical and bioprocessing contexts.

Q1. Which microorganism is most commonly used industrially for amyloglucosidase production?

• Aspergillus niger
• Bacillus subtilis
• Saccharomyces cerevisiae
• Pseudomonas putida

Correct Answer: Aspergillus niger

Q2. Between submerged fermentation (SmF) and solid-state fermentation (SSF), which strategy often yields higher amyloglucosidase titres using filamentous fungi on agro-residues?

• Submerged fermentation (SmF)
• Solid-state fermentation (SSF)
• Both yield identical titres irrespective of substrate
• Continuous fermentation only

Correct Answer: Solid-state fermentation (SSF)

Q3. Which carbon source commonly acts as an inducer for amyloglucosidase synthesis in filamentous fungi?

• Starch (raw or soluble)
• Glucose
• Glycerol
• Peptone

Correct Answer: Starch (raw or soluble)

Q4. The optimal pH range for most Aspergillus-derived amyloglucosidases activity and production is typically:

• pH 2.0–3.0
• pH 4.0–5.5
• pH 7.0–8.5
• pH 9.0–10.5

Correct Answer: pH 4.0–5.5

Q5. What is the typical optimum temperature for activity of industrial amyloglucosidases (glucoamylases) from Aspergillus species?

• 25–30 °C
• 35–40 °C
• 50–60 °C
• 80–90 °C

Correct Answer: 50–60 °C

Q6. Which assay is most commonly used to quantify amyloglucosidase activity by measuring reducing sugars released?

• DNS (3,5-dinitrosalicylic acid) reducing sugar assay
• Bradford protein assay
• Lowry total protein assay
• Iodine-starch colorimetric assay

Correct Answer: DNS (3,5-dinitrosalicylic acid) reducing sugar assay

Q7. What is the standard initial downstream step used to concentrate and fractionate crude amyloglucosidase from culture supernatant?

• Ammonium sulfate precipitation
• Ion-exchange chromatography as first step
• Gel filtration chromatography as first step
• Ethanol extraction of protein

Correct Answer: Ammonium sulfate precipitation

Q8. The addition of Ca2+ to preparation buffers for fungal amyloglucosidase primarily results in:

• Complete inactivation of enzyme
• Enhanced thermostability and structural stabilization
• Strong competitive inhibition of catalytic site
• Precipitation of enzyme as insoluble complex

Correct Answer: Enhanced thermostability and structural stabilization

Q9. Which heavy metal ion is known to strongly inhibit amyloglucosidase activity by interacting with thiol groups?

• Mg2+
• Ca2+
• Hg2+
• Zn2+

Correct Answer: Hg2+

Q10. What is the commonly used gene name encoding glucoamylase in Aspergillus niger?

• glaA
• amyE
• gaB
• amyZ

Correct Answer: glaA

Q11. Which immobilization matrix is widely used for repeated-batch starch hydrolysis with amyloglucosidase?

• Calcium alginate beads
• Free enzyme in solution only
• Activated carbon powder
• Liquid paraffin emulsion

Correct Answer: Calcium alginate beads

Q12. The principal final product of amyloglucosidase action on starch is:

• Maltose
• Dextrins
• Glucose
• Fructose

Correct Answer: Glucose

Q13. By definition, one international unit (U) of amyloglucosidase activity is the amount of enzyme that liberates:

• 1 mg of protein per hour
• 1 µmol of reducing sugar (as glucose) per minute under assay conditions
• 1 mmol of ATP per minute
• 1 µg of substrate per second

Correct Answer: 1 µmol of reducing sugar (as glucose) per minute under assay conditions

Q14. Which agro-industrial substrate is frequently used as both carbon source and solid support in SSF for amyloglucosidase production?

• Wheat bran
• Sawdust without supplementation
• Pure glucose powder only
• Synthetic agarose gel

Correct Answer: Wheat bran

Q15. What is a primary advantage of fed-batch cultivation for industrial amyloglucosidase production?

• Maintains substrate at high inhibitory concentrations
• Prevents cell growth completely
• Maintains optimal substrate concentration to avoid catabolite repression and substrate inhibition
• Requires no process control

Correct Answer: Maintains optimal substrate concentration to avoid catabolite repression and substrate inhibition

Q16. Which membrane-based unit operation is commonly applied to concentrate and partially purify amyloglucosidase after crude clarification?

• Ultrafiltration
• Distillation
• Rotary evaporation
• Adsorption onto silica gel

Correct Answer: Ultrafiltration

Q17. N-linked glycosylation of fungal amyloglucosidases typically results in:

• Decreased secretion and faster degradation
• Increased thermostability and protease resistance
• Conversion to endo-amylase activity
• Loss of catalytic activity entirely

Correct Answer: Increased thermostability and protease resistance

Q18. In industrial starch processing, the primary commercial application of amyloglucosidase is:

• Production of lactic acid directly from starch
• Saccharification of starch to produce glucose and high-glucose syrups
• Cellulose hydrolysis for bioethanol
• Direct polymerization of glucose

Correct Answer: Saccharification of starch to produce glucose and high-glucose syrups

Q19. In fermentation kinetics, which parameter represents the maximum specific growth rate of the microorganism used for amyloglucosidase production?

• Ks (half-saturation constant)
• μmax (mu max)
• Yp/s (product yield coefficient)
• qm (maintenance coefficient)

Correct Answer: μmax (mu max)

Q20. For genetic overexpression of amyloglucosidase in Aspergillus hosts, which promoter is commonly used for strong, constitutive expression?

• gpdA (glyceraldehyde-3-phosphate dehydrogenase) promoter
• Lac operon promoter
• T7 promoter
• araBAD promoter

Correct Answer: gpdA (glyceraldehyde-3-phosphate dehydrogenase) promoter

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