Case study 2

Question 1

antibiotic

Answer 1

type of antimicrobial drug used in the treatment and prevention of bacterial infections. They may either kill or inhibit the growth of bacteria. Antibiotics are not effective against viruses (as viruses are not alive).

Question 2

antibiotics target

Answer 2

1. cell wall synthesis
2. cell membrane
3. RNA polymerase, DNA
4. protein synthesis

Question 3

In order for antibiotics to be effective

Answer 3

bacterial cells must be actively growing

Question 4

Bacteriostatic

Answer 4

pauses the cell

Question 5

Bactericidal

Answer 5

kills the cell

Question 6

synergistic

Answer 6

combined effect of both bacteriostatic and bactericidal antibiotic to increase the efficiency

Question 7

Mechanisms of antibiotic resistance

Answer 7

Plasmid DNA encodes genes which have antibiotic resistance. Each method of resistance, represents an energy cost to the cell. Cells are viable as a result but there is an energetic cost which can be observed in the growth rates.

Question 8

Penicillin

Answer 8

Extracellular product, three genes code for penicillin pcbAB pcbC penDE. Kills by interfering with the production of cell walls (inhibits peptide cross-linking, Cell wall is weakened, causing osmotic imbalance and cell death)

Question 9

Primary metabolite

Answer 9

Produced during exponential growth. Example: alcohols, biomass

Question 10

Secondary metabolite

Answer 10

Produced during stationary phase, Non-growth associated, Production (inhibition) depends on growth conditions ([Carbon]?) Often significantly over produced. Often produced under unbalanced growth conditions (stress)e.g penicillin

Question 11

Penicillin production

Answer 11

fermented in a fed-batch process. Penicillin only starts getting produced once substrate levels reach a certain level (Product formation is inhibited by substrate)

Question 12

Penicillin extraction

Answer 12

Penicillin recovery occurs in three successive stages:
• 1. Removal of mycelium (secreted product!)
• 2. Counter current solvent extraction
• 3. Treatment of crude extracts

Question 13

What are antibiotics, how do they work and why are they important

Answer 13

MOA varies (cell wall/protein) biosynthesis; but requires actively growing cells

Question 14

How are antibiotics produced at an industrial scale

Answer 14

Antibiotics are secondary metabolites that are typically produced via fed-batch fermentations.

Question 15

What strategies can be used to make the production

of antibiotics more efficient

Answer 15

Improvement of antibiotic titres has depended on both bioprocess development and strain selection and improvement (random mutagenesis, GMO)