Batch - Mass and Kinetic Balances Flashcards
What are the two most important quantitative parameters for fermentation design?
Yield and Productivity
What are the three main fermentation modes?
Batch, Continuous, and Fed-Batch
What is the specific growth rate?
A rate parameter that measures how quickly a microorganism grows in it’s exponential phase
What are the four phases of biomass growth (in a batch)?
1) Lag phase
2) Log or exponential growth phase
3) Deceleration phase
4) Stationary phase
What generally causes the stationary phase?
There is no more substrate to be consumed and converted into biomass
What is the growth rate formula for biomass?
dx/dt = u x [u is the specific growth rate]
What is the integrated and log form of the growth rate formula for biomass at time t?
ln(xt) = ln(xo) u t [t is time, x is biomass concentration, and u is specific growth rate]
How would a yield of biomass (x) from substrate (s) be written?
Ysx [ s -> x]
What are the two types of productivities?
Volumetric productivity and Specific productivity
What is volumetric productivity?
It is concentration of a species per unit of time. [mass per volume per time]
What is specific productivity?
It is yield of a species per unit time [mass per mass per time]
What is rs (r sub s)?
specific substrate consumption rate
What is rx (r sub x)?
Specific growth rate or u
What is rp (r sub p)?
Specific rate of product formation
what is rco2 (r sub co2)?
Specific CO2 production rate (CER)
What is ro2 (r sub 02)?
Specific oxygen consumption rate (OUR)
Yields are typically normalized to what two components?
Substrate or biomass
What is the substrate mass balance for a batch reactor?
dcs/dt = -rs x
What is the product mass balance for a batch reactor?
dcp/dt = rp x
What is the product biomass balance for a batch reactor?
dx/dt = u x
What are the 7 characteristics of a batch reactor?
1) constant volume (no flow in or out)
2) All medium is in the fermenter at inoculation (no adding substrate)
3) Growth is not limited at the beginning of the fermentation (U = Umax)
4) Dynamic process (changes with time)
5) Low volumetric productivity at the beginning
6) Versatile
7) No issues with mutations or contaminations
