Download Metabolites * primary and secondary

Metabolites – primary and
secondary
Learning Outcomes
• Compare and contrast the processes of continuous culture and batch
culture.
• Describe the differences between primary and secondary
metabolites.
Metabolism and metabolites
• Metabolism
(process)
• Sum total of all the chemical reactions
• Processes produce
• New cell and cell components
• Chemicals
• Waste products
• Metabolites (products)
• A substance produced during cell processes
Primary and secondary metabolites
• Primary metabolite
• Substance produced by organism
as part of it’s normal growth
• E.g. amino acids, proteins,
enzymes
• Production of primary metabolites
matches the growth in population
• Secondary metabolite
• A substance only produced
at a particular growth phase
• No direct involvement in
fundamental metabolite
processes
• Production usually begins
after the main growth phase
of the micro organisms
Primary Metabolites
• Primary metabolites are produced
during active cell growth [lag,
exponential, stationary], matches the
growth in population of the organisms
• Produced by all microorganisms
Secondary Metabolites
• Secondary metabolites are
produced near the onset of
stationary phase e.g antibiotic
chemicals
• Not produced by all
microorganisms
Batch culture
• Starter population is mixed with a specific quantity of nutrient
solution
• Allowed to grow for a fixed period
• Products removed
• Fermentation tank emptied
• Examples
• Penicillin production
• Enzyme production
Continuous Culture
• Nutrients are added and products are removed from the
fermentation tank at regular intervals
• Examples
• Insulin production from genetically modified E.Coli
• Production of mycoprotein
A batch fermenter
Why use Batch?
• Many secondary products are not growth associated
• Genetic instability
• Operability and reliability
• Economic considerations
Exam Practice – Unit 5 questions
• 99, 125, 141, 170
Q141 Unit 5 questions
Primary metabolites
A fermenter
Secondary metabolites