Team:Paris Bettencourt/Project/Manufacturing

The aim of our manufacturing project was to find a way to grow and distribute our strains easily and cheaply to reach as many people as possible. The product has to be simple and minimize the disruption to Indian habits.



Growth of our strains

Our project is designed for poor regions: the cheaper our product, the more people it can reach. Starting from this point, we didn't want to build labs in India, buy media and grow our strains in expensive structures. Therefore, we had to think of a cheap solution to grow the strains in a homemade media, made of common ingredients, cheap and readily available.
To avoid expensive and time-consuming treatment, an edible medium is sought. It could be directly used to cook either our distribution product or the Idli directly. The process would hence be quite simple and accessible to the population.
After some research, we selected 4 different homemade media to test with our 3 strains:
  • Water from the cooking of potato (potatoes cooked in 2L of water for 20min)
  • Water from the cooking of potato+sugar(10%)
  • Water from the cooking of rice (200ml of rice cooked in 2L of water for 10min)
  • Water from the cooking of rice+milk(10%)

We also wanted to see if the concentration in potato had an influence so for each media made out of potato water, we tried two different concentration of potatoes: 190g/L (named ???????) and 250g/L (named ???????).
For each strain, we compared the growth of the strain in the homemade media with the growth in its "normal" media (respectively YPD, M17+Glucose 1% and YEL).


Packaging and distribution


One stake of our project is to give the strains to the population. Either community labs or users grow the strains, strains needs to travel from us to the community lab and then to the final user.
To answer this problem, we tried several methods, premilinarily working on a yeast: Saccharomyces cerevisiae mcherry.
We could have just lyophilized the strains but our goal is to design something cheap and easy to do for the locals, using only ingredients they have access to and not time consuming.
We first tried to make different kind of powders, but none of it was satisfying. Powders appeared not to be very convenient.
We realised a powder wasn't the best way to distribute our strains. We found better to make portions, easy to pack, with the possibility to pack several portions together. Portions must be easy to stock.
The most efficient and ergonomic shape appeared to be a cube. Moreover, the cube will mainly be added to Idli, made of rice, so rice flour seemed to be a logical ingredient, consonant with the dish, common in India and cheap.
Little by little, we succeeded to design an easy recipe, to cook small cubes made of rice flour and water: the VitaCubes. The idea was also to be flexible to every VitaCube maker means, therefore the recipe is not very strict and can be adapted to what the people have available.



Now that we have found a convenient distribution mean, we need to be sure that it keeps our strains alive and to know how long it can be stored.
We conducted several survival test on the VitaCubes, using S.cerevisiae mCherry and L. lactis. To make these test, we were plating the liquid solution containing the strains before adding it to the flour, in order to know how many cells we put in the VitaCube. After a define period of drying, we immerse the VitaCube in 10ml of osmosed water and plated the solution obtained to count the numbers of cells that survived in the cube.
At first, we obtained very different results, even if the cubes were all plated after one day of drying. We realised the time of ??? of the cube in the water had an influence over the survival rate: the longer it was, the bigger was the survival rate. This is due to the revival of cells once back in water.
Therefore, we designed a one week experiment: we made plenty of VitaCubes on the same day, and then each day, we plated one cube. Each day, we respected the very same conditions, every step was timed.
Graphs!!!!!!!!!!
We can see that the yeasts are very resistant and have a very high survival rate, decreasing very slowly over time. The survival rate is even higher than 1 because yeasts grow very fast, so in 20 minutes in the water, they divide. In conclusion, the yeasts can be stored more than one week in a VitaCube.
For L. lactis, the survival rate is low since the first day and is decreasing very quickly every day. After 4 days of drying, the survival rate started to be very very low. Nevertheless, there are still around 105 cells in a VitaCube after one week, each is far enough to make a culture from it.(and to make Idli?)
Looking at the graphs, we can see that the mix of both strains doesn't influence their survival.