Team:Paris Bettencourt/Project/Phytase

Introduction

Anemia affects one third of the world's population, most of which is iron deficiency related (Gupta et al. 2015). Anemia and similar mineral deficiency diseases are primarily widespread in developing countries like India, due to their diet mainly made up of cereal grains and seeds such as rice (O'Dell et al.1972). In these types of food, the iron bioavailability is substantially reduced by the presence of phytic acid (C6H18O24P6) that inhibits the absorption of various minerals in the intestine by forming insoluble salts. Current research to increase the bioavailability of iron or zinc involves the bioengineering of crop plants which not only poses challenges in terms of the production of efficient genetically modified crops but also requires extensive research for drawing any conclusion on the strain sustainability (Gupta et al. 2015). We propose an alternative strategy that focuses on the bioengineering of microorganisms involved in the fermentation of Idli, a dish widely used as primary food source in a large part of India. Indeed,

Cereals, which are highly consumed in India, contain the highest levels of phytic acid.

Idli is mainly made of cereals. The majority of minerals present are not absorbed. We are looking for a solution to this bioavailability problem.


Figure 1: Phytic acid in complex with calcium, magnesium, zinc and iron


Phytase

Figure 2:Phytase hydrolyzes phytic acid.

Phytase could be a solution to this problem. Phytase is an enzyme which hydrolyzes phytates created by phytic acid when it is complexed to a mineral. Thanks to this, the cations will be liberated and may be absorbed by the organism.

Phytase is naturally produced by Saccharomyces cerevisiae (Veide, 2006). This yeast contains negative regulator genes, and because of it, the phytase is produced in very small quantities.

The negative regulators are produced 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 colormetric kit to measure the quantity of phytic acid .


Results

We have not result, but if we had more times, we may continue experiments to have more concluding results. The results we have already leads us to believe that there is much chance that his works.


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).