Team:Paris Bettencourt/Project/Phytase

Ferment It Yourself

iGEM Paris-Bettencourt 2O15

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Phytase

Introduction

Phytic acid (C₆H₁₈O₂₄P₆) is a molecule that inhibits the absorption of different cations like iron, zinc, copper, magnesium, calcium and cobalt. It makes insoluble salts around these elements, like phytate. These complexes are not soluble, so it is harmful to digestion and absorption of the minerals wich are essential to growth. They are difficult to find in our alimentation, and the absence of this minerals may be the cause of the food deficiency.

Cereals are the food in which we find the more phytic acid.

The idli is mainly made of cereals. The majority of minerals present are not absorbed. We want to find a solution to the food deficiency, like the study of vitamines.

Figure 1: Phytic acid can bind to calcium, magnesium, zinc and iron.

Phytase

Figure 2:Phytase hydrolyzes phytic acid.

The solution we found is the phytase. It’s an enzyme which hydrolyses phytates created by the phytic acid when it is linked to a mineral. Thanks to this, the cations will be liberated and may be absorbed by the organism.

So, we have to find a way to this system be integrated in the food, because if we just add the enzyme to the bacterial mirobiome, it will be present only on the beginning and the phytase will be not produced.

The phytase is an enzyme naturally produced by Saccharomyces cerevisiae (Veide, 2006). The yeast contain negative regulator genes, and because of it, the phytase is produced in very small quantity.

The negative regulators are producted by two important genes in Saccharomyces cerevisiae : PHO80 on chromosome 15 (325.249pb - 326.130pb) and PHO85 on chomosome 16 (492.018pb - 493.037pb). With the deletion of one or both of these genes, the phytase may be overproduced.

Design

To test our experiment, we used a kit which permit to dose the phytic acid by colorimetry.

Results

Bibliography

Veide, J. & Andlid, T. Improved extracellular phytase activity in Saccharomyces cerevisiae by modifications in the PHO system. International Journal of Food Microbiology 108, 60-67 (2006).