Team:Paris Bettencourt/Notebook/Idli and micro-organisms

July 2nd to 9th



I experiented different recipes to make idli come from India. I tried to do it with different rice and lentill (called dall in india). Finally, I chose to do this recipe with basmati rice and indian dall.


I did a media from an idli preparation. After fermentation of 18 hours, of ildi composed of 3 glasses of rice (75ml) and 1 glass of dall (25ml) before the soaking phase, I took water and butter mixed it together in 500ml bottle, and did an autoclave. I called this media "idli water", and it look like previously. I will just use the clear phase.

July 12th to 14th and 16th to 18th



I did grow ''Saccharomyce cerevisiae'' with mCherry and geneticin resistance genes in idli. I added 2 ml of a yeast growth solution (YPD) with an OD600 of 0.455 (around 1.2 x 107 cfu) after the soaking phase and the mixing and grinding of rice (3 glasses of rice ~ 75ml) and dall (1 glass of dall ~ 25ml) together.The first try was to see if there are the fermentation process will this laboratory strain. After the fermentation time, I had plated the µorganisms come from the butter phase (middle phase between water on the top, and grind matter in the bottom of the erlenmeyer) on YPD with geneticin. I observed a lot of part of crush rice or dall, and just few colonny, not red like expected with the mCherry gene. The second try was more successful. This time I diluated the butter 10 and 100 time before plating, always on YPD and geneticin. I observed few colonies for the plate with the 100th and around 30 with the 10th.

July 20th



I did a culture on TECAN plate of few species that was ''Saccharomyces cerevisiae'' with mCherry on chromosom, with Lactobacillus plantarum NC8 and Lactococcus Lactis MG1363 on their respective media (YPD, MRS and M17) and on "idli water" and on water, with and without antibiotics (respectivly geneticin disulfate, and erythromycin for the 2 bacteria).
I did a TECAN mesure after an over night growth of 18 hours, and we obtain the table followed. We can see that the mesure was nonsens.

July 29th



Test of the titration protocol with spectrophotometer for the Vitamin A (protocol titration)
I tested this protocol and tried to calibrate it. I used, like food sample, 1g of rice and I did 8 bottles with 8 different concentrations of pure vitamin A from 10 -1 to 10 -8 mg.ml-1.

Results :
We can just observe concentrations higher than 10-3mg.ml-1.
dilution of the initial concentration Value of the spectrophotometer
10-1 1.625
10-2 0.078
10-3 0.034
10-4 0.008
10-5 0.002
10-6 0.005
10-7 -0.001
10-8 0.000

August 10th



I did electrocompetent cell of ''Lactobacillus plantarum'' with a particular protocol
It worked very well.

August 14th



I had done idli protocol, with 75 ml of rice, for 25 ml of dall. After grinding and mixing, I added 2ml of ''Saccharomyce cerevisiae'' (with mCherry gene and geneticin resistance) that contained 108 cells. I had plated at t0 and 2h, 4h, 6h, 19h30, 21h30 after t0 three different positons (middle top, lateral middle and bottom middle) at three different concentrations (100, 10-2 and 10-3).

Like we can observe, the areas where I take sample for plating don't matter, and the yeast did't grow very well : just a doubling size of population during 22 hours of culture.