Team:DTU Denmark/results

Two strains were grown under diferent substrates, Glucose, Galactose, Glucose and Galactose and Ethanol. These two strains that we denominate Redoxilator and Leaky correspond to the redoxilator with a constitutive promoter and a minimal promoter repectivelly.

Growth rates (h-1) obtained for the two strains on diferent carbon sources

As expected, both strains showed different profiles of growth accordingly to the substrate. For Glucose and Galactose, the growth curve showed two exponential phases, the first one corresponding to the growth on Glucose and the second corresponding to the growth on Galactose. Although the initial OD was similar in both cases, the growth on Galactose showed an even longer lag phase than the glucose. Finally, as expected, the substrate reporting less growth was ethanol. For the Redoxilator, the growth solely on Glucose showed a longer lag phase compared to the mixed substrate, probably due to a lower initial OD.

Growth profile (OD) of the Redoxilator for the different carbon sources

Growth profile (OD) of the Leaky for the different carbon sources

Regarding the GFP signal, all substrates showed different profiles. Nevertheless, the fermentative substrates, Glucose and Galactose, showed higher values of GFP than the respirative substrate, Ethanol.

GFP signal of the Redoxilator for the different carbon sources

GFP signal of the Leaky for the different carbon sources

Although these results are accordingly to what was expected, it is important to mention that these cultures didn’t have comparable growths, so, in order to subtract this variability of the growth, one should normalize the GFP expression with OD. Additionally, to the GFP values, the residual values for each case were subtracted.

GFP signal corrected from the residual signal, normalized with growth of the Redoxilator for the different carbon sources

GFP signal corrected from the residual signal, normalized with growth of the Leaky for the different carbon sources

One other aspect that is worth instigating is the variation of the GFP signal with growth. In other words, if growth is correlated with GFP signal.

Variation of the corrected GFP signal with growth of the Redoxilator for the different carbon sources

Variation of the corrected GFP signal with growth of the Redoxilator for the different carbon sources