Part:BBa_K1686046:Experience

Applications of BBa_K1686046

Part 1 : Curdlan production

We produced some Curdlan compared to non transformed strain of DH5α. We analyzed data with a student test to prove our results are significant. The theoretical concentration obtained in the Control condition corresponds to the non significant measure (background signal).
N.B. We realized these figures by doing the average of all production results in each medium.

Figure 5: Quantitative analysis of purified Curdlan with aniline blue

→ Each medium can be used for the Curdlan production. But, we can’t compare these two results and say that produced Curdlan quantity is higher in LB than in M63 medium because productions are not realized at the same time in these cases.

In following results, we have studied production in M63 and LB media started at the same time.

Figure 6: Quantitative analysis of purified Curdlan with aniline blue

→ Now, thanks to a statistic test, we can conclude that Curdlan production is doubled in LB medium compared to M63 medium.

LB medium has an unknown glucose concentration contained in yeast extract whereas in M63 medium we have controled this parameter. We suppose that LB glucose concentration is higher than in the second medium. That will be explain the difference between these two conditions.

However, compared to Saccharomyces cerevisiae, our results are very low: about 10 to 20µg/mL for Bacteria to 100µg/mL for Yeast.

We have tried some optimization protocols but without success.

Part 2. Curdlan characterization
To verify produced molecule is Curdlan, we analysed samples with a polarimeter. The reference used was Curdlan bought to do standard range for the quantitative analysis with aniline blue.

A substance is optically active or has a rotatory power when it deflects polarization plane of light from an α angle. This rotatory power is related to the presence of one or more asymmetric carbon within the molecule. All sugars (except dihydroxyacetone) are chiral molecules, so they all have a rotatory power. This property allows the polarimetric determination of sugars in pure solution thanks to the law of Biot.

There are two types of optically active substances:
✵Those which deflect polarization plane of light from an α angle to the right. The measured angle is positive and the substance is in dextrorotatory form.
✵Those which deflect polarization plane of light from an α angle to the left. The measured angle is negative and the substance is in levorotatory form.

Results
– Results were obtained with a Jasco P-2000 polarimeter.
– Measures are done at 25°C.

	Optical rotation monitor
Reference	-0.1902
produced Curdlan	-0.1982
Control	0.0590

At the end...

We have obtained 3.44g of Curdlan in one month of production and with one single gene!

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