Team:Imperial College London/Wetlab/Results/Autoinduction/Gluonly

Experiment: In a 96-well plate, initial concentrations of glucose ranging from 0.01% to 0.05% of the culture were studied. There are several possible effects that it could exert on cell growth and the hypotheses are stated below:
1.The lower the initial amount of glucose in the medium, the shorter the time taken for the population to reach saturation level.
2.The lower the initial amount of glucose in the medium, the lower the growth rate prior saturation level, but no delays on the time taken to reach saturation.
In addition, we also know that a lower amount of glucose means that the population will grow less and saturate at a smaller value.
Figure 1: Glucose growth curves We can see that initially, there is an exponential growth phase followed by saturation of growth once glucose has been used up. In this diagram, effects of different glucose concentrations on growth rate are not apparent. Instead, a more informative measure is the growth rate during the exponential growth phase. As we know, if the OD curves follow exponential expression in the form of:
y=yoexp(rt)
where r is the growth rate, t is the time in hours, y is the absorbance/OD over time and yo is the initial absorbance/OD, we can simplify the relationship such that:
log(y)=log(y_o+ rt)
So when we plot log y against t, there is a linear relationship in the exponential growth phase, so we can estimate the growth rate r from there.

Figure 2: Log data of optical density showed for exponential region for the first 150minutes of growth.