Microbial Kinetics Flashcards
What is thermodynamics?
Is the reaction possible (without an input of energy to force it).
only starting and end points are important.
about how stable a species is in its environment.
What is kinetics?
Rates of reactions.
How fast a reaction will happen.
Depends on all steps in the reaction, activiation energy barrier, usually also temp, concentration of reactants and products
faster metabolic reactions –> faster the microbial growth
What are the stages of a typical growth curve?
- Lag Phase
- Exponential Phase
- Stationary Phase
- Death/Decline Phase
What is the lag phase?
cells adjust to the new environment (e.g., activate or synthesis new enzymes)
What is the exponential phase?
Cell growth phase. Exponential growth as microbial populations grow by cell division.
Generation time = doubling time.
Exponential growth can not be sustained
What are some limitations on the growth of microbes?
Exponential phase is limited by:
- temp
- pH –> can change due to the toxic build up of waste
- lack of substrate (PED) or essential nutrients
- changing environmental conditions
- predation
- lack of space
What are some adaptation strategies for microbial growth?
- become smaller for a higher surface area to volume ratio
- grow slower - slower kinetics
- alter metabolic pathways or change enzyme type to optimise growth in the real world
- form spores inside (endospores) or outside (exospores) to preserve key components of cell in a small dormant package.
What is the yield coefficient?
substrate-to-biomass yield. converts between cell growth rate (dX/dt) and substrate utilisation rate (dS/dt).
how many cells are produced by substance per amount used.
What is the Monod equation
The rate of change of microbial biomass.
most widely used for describing specific growth rate as a function of substrate concentration.
