Chemostats: From the Lab to Industry

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Chemostats From the Labto Industry
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Actual Lab Use
-Genetic/evolution experiments -Growth rate
experiments -Steady state experiments
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Industry Use
-Continuous production of chemicals
(hydrogen, formaldehyde, food additives) -Ethanol
production
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Issues With Chemostats
-Expensive (media usage) -Time Consuming
(sampling, set up, sterilization) -Growth Rate
Oscillation
Delta Capacitance
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Modeling a Chemostat
Assumptions

• Well Stirred
• Growth rate depends on nutrient availability
• Limit nutrient to one generic (G)
• Nutrient consumption occurs continuously
• Constant flow rate
• Law of Mass-Action describes interactions between
  species (Y) and generic nutrient consumption

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G- Nutrient Concentration at any time t. Y-
Yeast Concentration at any time t. mu- Growth
rate depends on nutrient availability. gamma
Yield of species. F- Flow rate V-Volume of
Chemostat
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Washout of Species
Sensitive Strain (K-R-)
Killer Strain (KR)
Analytically, the steady state of Y is a linear
relationship of F/V
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Two Species Interacting

• Types of interaction
• Competition
• Disease dynamics
• Predator-Prey dynamics (NEXT ASSIGNMENT)
• Toxic/Killing-Parasite dynamics (my research)
• Example Yeast cells infected with a certain
  virus produce a killer toxin that kills only
  uninfected yeast strains.

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New Assumptions

• For simplification, assume growth rate depends
  directly on nutrient concentration (G).
• Death of sensitive yeast (Y) will occur,
  proportional to how much infected yeast (I) is
  present.
• Law of mass action will describe interactions.

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-Nutrient Reservoir Concentration
concentration/volume -Growth rate
volume/time -Yield factor 1/volume -Flow
rate volume/time -Vessel Volume
volume -Death rate of Uninfected Yeast 1/time
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Analytical Results
-For washout of Infected strain, we arrive at the
following condition -Washout depends on k
and F/V. It turns out that k is a hyperbola
function of F/V.
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Things To Be Done

• Spatial dependence
• Growth kinetics
• Dependence on temperature, pH,