Bacteria Culturing

What are the types of cultures?

Batch & Chemostat growth

Batch Culture is aka:

Closed culture

What does a batch culture involve?

Growing bacteria in a closed container with a fixed volume of media

What does a chemostat growth culture involve?

Growing in bacteria in an open container with nutrients continuously being added

What kinds of media are there?

liquid, solid, defined, complex, differential, & selective

What is the difference between defined & complex media?

Defined is made the same way every time

What are the phases of bacterial growth curves?

Lag, exponential growth, stationary, death or decline, & long term stationary

What is the lag phase?

cells are maturing or doubling, synthesis of RNA, enzymes, etc. represented by horizontal line

What is the exponential growth phase?

Population undergoes constant doubling, favorable conditions = longer slope, faster growth= steeper slope.

What is the stationary phase?

Flat portion of the curve, rates of cell death= rates of cell division

What is the death/decline phase?

(if limited supply of nutrients) living cells deplete nutrients & waste product accumulates. Death rates are high.

What is the long term stationary phase?

When bacteria is observed, high rates of cell division & death.

How can bacterial growth be calculated?

Exponential growth equations

For 100% efficient binary fission, what is the equation?

P= P₀*2^(t/g)

P is:

Current population size at time t

P₀is:

Initial population cells

t is:

How much time elapsed since t=0

g is:

Generation time

(t/g) is:

number of generations since t=0

For <100% binary fission, what is the equation?

P=P₀*(1+e)^(t/g)

What is the Monod equation for?

describing a mathematical relationship between the concentration of a limiting nutrient and bacterial growth rates

What is the Monod equation?

μ= d[P]/dt= μ_max[S]/K_s+[S]

What does μ mean?

growth rate of population

What does [S] mean?

Concentration of limiting nutrient

What does K_s mean?

concentration of the limiting nutrient at which the current growth rate is half of the maximum