Cultivation Of Bacteria + Maths Flashcards
Why is batch culture (growing bacteria in flask) called a CLOSED CULTURE
No nutrients/toxic products or dead bacteria are removed from cultivation
What 6 conditions do bacteria need to grow
1- nutrients
2- optimal temp
3- ph
4- salinity (naCl conditions)
5- moisture/water
6- gas (02 or co2) : respiration
Why does bacteria need nutrients and gas
Because they use energy (from nutrients in metabolism) but also produce it via respiration
what are the 4 types of macronutrients which bacteria need for ion provision
1- proteins (provides N)
2- Lipids (provides C,O)
3- carbohydrates (provides C,O)
4- nucleic acids (provides N)
What are the 4 essential elements/micronutrients
1- carbon
2- oxygen
3- nitrogen ( synthesises dna)
4- phosphorus (synthesises new dna )
Which 2 types of media provide the nutrients needed
1- chemically DEFINED media
2- undefined COMPLEX media
What is chemically defined media
Media which gives compounds which directly produced micronutrients like N,C,O,P
Eg glucose
What is undefined complex media
Media which gives complex compound which breakdown into things like Lipids, carbs, proteins
Eg yeast extract
What 2 variables are needed to measure amount of bacteria
Population density per volume (optical density, turbidity)
Population number (ie plating, counting, flow cytometry)
Which technique is used to measure popn density
Optical density / turbidity
What are CFU counted in the plating method
Colony forming units
Why would you watch cell growth
To see if cells are healthy for division
How do you work out from log2 the generations of division
Eg given you have 32768 cells how many division
Log2(number) = divisions
Eg 2^0 = 0 division (1 cell)
2^1 = 2 divisions because log2(2) = 1
How do you work our generation time from a graph with time and number of bacteria plotted
G= total time / number of division (3.3 log b/B)
How do you work out number of divisions
Log(final number) - Log (initial)
/
Log(2) = 0.32
=3.3logb/B
What are bacteria called which live in harsh conditions
Extremophiles
Name the 4 types of bacteria according to their optimal temp
1- psychrophile (4C)
2- mesophile (body temp)
3- thermophile (60)
4- hyperthermophile (80)
Name the 3 types of bacteria according to ph optimum
1- neutrophile(ph 7)
2- acidophile (acid 10^-8 upwards)
2- alkaliphile (alkali 10^-6 downwards)
What ph do all bacteria internal environment have
7
What are the 4 types of bacteria according to salinity content (naCl)
1- non halophile (no salt)
2- halotolerant (low salt)
3- halophile (mid)
4- extemeophile (high salt)
Name the 5 types of bacteria depending on their 02 need
1- obligate aerobes : need 02 a lot (grow on surface)
2- obligate anaerobes: don’t need 02- grow at bottom
3- facultative - grow dispersed , can have low or high 02
4- microaerophillic - don’t need a lot but need 02
5- aerotolerant - can grow anywhere like facultative
Chemostats are used to grow bacteria like batch culture, what is the different
They are in continuous culture/ open culture
Nutrients are added constantly and dead cells removed / waste
What is steady state meaning in chemostat growth of bacteria
Once equilibrium is reached , the volume , population density, growth rate stay constant
What parameters don’t change in chemostats
Volume
Ph
Oxygen
Nutrients
Waste conc
Popn density
How do you work out the dilution rate in chemostats
D = flow rate (of media) / volume
Why does flow rate need to be constant with growth rate
Because if flow rate exceeds growth rate the media will wash bacteria away
If growth rate exceeds flow rate the nutrients will deplete = go into stationary or death phase
What is used to grow single cells
Microfluidics
Media is supplied (open culture) on microfluidic slides
Agar tracks allow growth of bacteria linearly on the micro fluidic slide
