BIOMED Engineering Experimental proposal for Growth E.Coli
March 31, 2014
The purpose of this study is to create
and validate a mathematical model of
a growth curve of bacterial behavior
after thermal shock at various
Escherichia coli (E. coli) is a type of bacteria
commonly found in the intestinal tracts of
The growth and decay rate are also affected
Initial concentration of bacteria
Presence of antibacterial substances
Oxidation reduction potential
In our experiment, we demonstrate how the
growth curve is affected by thermal shock
E. Coli grows well between 21oC to 50oC with
an optimum at about 37oC .
E. coli can divide every 20 minutes
At temperatures of 0°C (32°F) E. coli are
unable to divide, keeping the population
E. coli is killed above 70°C (160°F)
Lag phase: the population remains temporarily
Log phase: the cells divide at a constant rate
depending on temperature conditions
Stationary phase: the population
growth is limited by
Death phase: the
number of cells decreases
The E.coli Growth Curve
The growth curves of colonies shocked
at temperatures (45-650C) demonstrate
longer lag times but accelerated
exponential growth when compared to
a control grown at 37°C
WE WILL APPLY THIS
EQUATION TO CREATE THE
GROWTH CURVE MODEL
(Nmin) = minimum
population of E.coli
(Nmax) = maximum
population of E.coli
r = Temperature-dependent
C= Adjustment factor
N= number colonies at time t
Materials and Equipment
Spectrophotometer and cuvettes
1000μL and 100μL micropipettes
Beakers and hot plates
Distilled water and deionized water
Culture of E.Coli
Nutrient broth as a food source
Initially raise bacterial environment
temperature to 450C, 550C, 600C, and 700C
Growth continued at 370C after thermal shock
Control group grown at 370C
Create a concentration ladder
Measure cloudiness in a test tube as the number
of cells increase (turbidity) using a
Mintab and MATLAB software
Plot mathematical growth curve and
experimental growth curves
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