Absorbance analysis

Calculation of growth rate of the population for varying blank levels

28 ºC

• Growth rate variation is low for different blank values(0.004-0.005)
• See figure 5 for an example.
• The growth rate of the culture seems to be constant at the values mentioned (0.004 to 0.005 /min) but the positive control seems to be higher. We believe that this variation is due to noise.

42 ºC

• The linear trend in variation of the blank can be explained due to evaporation effects. In this case, the variation was accounted for directly, so it was unnecessary to evaluate the growth rate for different blank values.
• The y-intercept in the plot is not reliable but the trend is apparent.
• We can observe exponential growth for the first 100 minutes (figure 6) at a rate of roughly 0.012 /min.

28 degrees Celsius

Figure 1: Absorbance at 28 degrees Celsius

42 degrees Celsius

Figure 2: Absorbance at 42 degrees Celsius
Plotting raw absorbance data on its own does not provide sufficient information about the effects of temperature on our system. Therefore, further analysis is required. This includes recording the variation in absorbance of the blank well (containing only the M9 medium) and normalizing absorbance data against the latter to spot ay possible trends in growth rate variations at different temperatures.