L12 - Industrial biotech: microorganisms in industry

Question 1

What are the ancient uses of microbial processes?

Answer 1

• Beer brewing (Middle East, 7000+ years ago).
  
  • Fermented milk products even older.
  • Early processes relied on spontaneous microbial activity
• traditional products (alcohol, vinegar, fermented milk products)

Question 2

Who is pasteur and why is he the father of industrial microbiology?

Answer 2

• Refuted spontaneous generation (microorganisms arise only from pre-existing microorganisms).
• Developed vaccines (rabies, anthrax).
• Introduced pasteurization (brief heating to kill bacteria in food).
• Work in industrial microbiology (wine spoilage) led to medical microbiology advances.

Question 3

What are some modern microbiology techniques to develop industrial produces?

Answer 3

• First industrial use: Carlsberg brewery (1884) – pure yeast cultureSaccharomyces pastorianus.
• Other important microbes & products:
  
  • Glycerol–Saccharomyces cerevisiae
  • Acetone & Butanol–Clostridium acetobutylicum
  • Citric acid–Aspergillus niger
  • Penicillin–Penicillium chrysogenum
  • Glutamic acid–Corynebacterium glutamicum, MNOs
  • enzymes for starch processing, laundry detergents (bacillus and aspergillus spp.)

Question 4

What is industrial biotechnology (IB)

Answer 4

‘White Biotechnology’ (vs. Red = Medical, Green = Agricultural).

Question 5

Why do we need renewable sources?

Answer 5

• Reduce fossil fuel use (environmental, economic, and political reasons).
• Shift towardsbiomass-basedproduction (esp. non-food-grade, cellulosic biomass).
• Concept of a‘Sugar Economy’(biomass → sugars → microbial conversion to chemicals).

Question 6

What is synthetic and engineering biology?

Answer 6

• Uses modular engineering principles & DNA synthesis for microbial engineering.
• UK government investment (£300M) →Synthetic Biology Research Centres&Genome Foundries.
• Scotland’sIndustrial Biotechnology Innovation Centre (IBioIC)– connects universities & biotech companies.

Question 7

Primary vs. Secondary products – differences & significance:

Answer 7

Primary products are the endproducts formed during fermentation microbial growth, such as ethanol, butanol, acetic acids, lactic acids

Secondary products are metabolites that are often produced after the organism’s growth phase, such as antibiotics or alkaloids, and are typically related to stress responses or survival mechanisms.

Significance: Primary products are essential for growth and reproduction, while secondary products may have industrial, pharmaceutical, or ecological importance.

Question 8

What can microorganisms do for us?

Answer 8

1. consume organic compounds (bioremediation)
2. produce fermentation endproducts
3. produce metabolic intermediates
4. produce secondary products (antibiotics) - usually strains militated or engineered for high production
5. produce proteins (enzymes recombinant theraputic proteins
6. produce biomass (single cell protein e.g. quorn )

Question 9

What are the 2 types of fermentations in terms of large scale growth of microorganisms?

Answer 9

• surface fermentations (grows on wet surfaces, good aeration, prone to contamination , hard to automate)
• submerged fermentations (grows in liquid media, uses bioreactors)

Question 10

What is the main challenge in growing aerobic organisms

Answer 10

oxygen supply

Question 11

Types of reactors

Answer 11

1. Anaerobic Fermenters:
   
   • Cylindroconical vessels (cone-shaped bottom to prevent cell buildup).
   • UsesCO₂ bubbles or slow mixingfor circulation.
2. Aerated Stirred Tank Reactors:
   
   • Most common type (e.g., for citric acid, penicillin).
   • Key features:
     
     • Sparger(bubbles air into the medium).
     • Impellers(Rushton turbines, marine impellers) for mixing.
     • Cooling system(jackets & internal coils) to remove heat.
     • Antifoam systemsto prevent foam buildup.
3. Airlift & Pressure-Cycle Reactors:
   
   • Used forvery large-scale production(e.g., Quorn fermentation).
   • No impellers –gas bubbles drive circulation(reduces energy costs & shear stress).

Question 12

How do primary and secondary products differ in microbial growth？

Answer 12

primary： produced during exponential (log) phase
secondary: produced as growth slows, and in stationary phase

Question 13

Types of fermentation processes

Answer 13

1. batch fermentation: all components present at start
   pros: simplest
   cons: inefficient use of reactor time, high downtime for cleaning and resetting
2. fed batch: feed concentrated nutrients to prolong production phase. (nutrients added gradually)
   pros: more efficient use of reactor time, essential when high nutrient levels prevent product formation
3. continuous: add fresh medium and remove spent medium at constant rate.
   pros: most efficient
   cons: not suitab;e for highly mutate strains which may used mainly for primary products revert