Lecture 2: Batch Culture Fermentation Flashcards
What is a batch culture?
A close-system culture that need:
specific nutrients
specific temps, pressure, aeration, etc
Only a few generations allowed to grow
Simple and commonly used
Can go from small to industrial (wine) scales
What are the pros and cons of shake flasks (batch culture)
+ easy
+ cheap
+ large number of experiments in parallel
- Data can be difficult to interoperate
- Dynamic conditions throughout the experiment & therefore experimental variability. E.g., pH from metabolism, nutrient levels
What are the pros and cons of bioreactors (batch culture)
+ Closed system = less risk of contamination
+ Controls certain conditions well
- Dynamic conditions throughout the experiment & therefore experimental variability. E.g., pH from metabolism, nutrient levels
What is the balance of each phase of bacterial growth?
Exponential, there is balanced growth
Lag: depends on history of the cells
stationary: depends on produced metabolic products
death: Hard to predict as cells begin to cannibalise each other or mutate to form subpopulations (NOT MUCH USE TO US!)
What are the two types of modelling of bacterial growth
Structured: modelling of substrate to product through consideration of metabolic pathways
Unstructured: ‘black box’ approach where metabolic pathways are ignored and modelling focusses on input/output
What is the Monod model/equation?
Analysis of the exponential phases is aided by focus on the ‘limiting nutrient’
The monod equation relates the limiting nutrient concentration to the population growth rate
𝜇=(𝜇_𝑚𝑎𝑥∙𝑆)/(𝐾_𝑠+𝑆)
What is metabolic flux analysis
Can only be used for well understood pathways
User optimises product formation by controlling range of genetic and environmental aspects
What is Rs?
Rate if substrate uptake
What is Ms
Maintenance coefficient - amount of substrate for cells to survive (but not divide)
Ms is related to S
