Growth curves: SST and FFT

Introduction:
This experiment was set up to measure the growth rates of our bacteria, expressing either of the two proteins fructan:fructan fructosyltransferase and sucrose:sucrose fructosyltransferase.
Our hypothesis is, that the growth of the bacteria producing the fructan:fructan fructosyltransferase will be slower, since it is using sucrose and turning it into inulin which is indigestible for the bacteria.

Method:
In order to produce this growth curve we took E.coli top10 transformed with the pJET plasmid containing FFT or SST and growed them in 50 mL fresh LB media (containing ampicillin).
We transfered 1 mL of overnight culture (ONC) to the fresh LB media and measured the optical density (OD) at 600 nm, every hour.
We also made a negative sample containing 1 mL of ONC with E.coli top10 and 50 mL of LB media (without ampicillin)

Results:
The data is given in a table (table 1) and can also be seen plotted on a logarithmic scale (figure 1). Hour nr. 7 is left out, because it was measured at OD 450 instead of OD 600, hence giving false data.

Discussion:
As you can see, clearly, FFT is decreasing the growth rate of the bacteria. This is most likely because FFT produces and indigestible polysaccharide from sucrose, disabling the bacteria in getting the energy. SST grow as fast as the negative test, which indicates that the protein does not have any disadvantages concerning growth. This is probably because SST produces a trisaccharide from sucrose, that the bacteria is able to digest.

Conclusion:
FFT is decreasing the growth rate of E. coli Top10 but not SST.