Deficiency

The World Health Organization recognizes iron deficiency (ID) as the most common and widespread nutritional deficiency in the world [1]. ID is rampant in developing countries and is especially prevalent among young children and pregnant mothers. Young children are particularly at risk due to the increase of iron required during periods of rapid growth. Similarly, expectant mothers require heightened levels of iron during pregnancy, and if this demand is not met, the transfer of iron to the developing fetus may be compromised. Unfortunately, once an infant is born with insufficient iron, it is not likely that iron supplies will be reacquired [2].

Due to weak health services and delivery systems, iron deficient has remained relatively resistant to prevention through public health interventions. Current prevention and treatment requires routine supplies of iron supplements or iron fortified foods that are not economically accessible to many populations with limited resources [3]. In addition, many of the iron-enriched foods provided by such programs are usually imported from outside sources instead of grown locally. Our aim is to eliminate the need for foreign imports of foods and supplements by increasing the bioavailability of iron within the native foods commonly consumed by developing populations.

Phytate

Phytate is the salt form of phytic acid, also known as inositol hexakisphosphate or IP6. This acid is responsible for the chelation of phosphorous and iron in plant tissues. Only ruminant animals such as cows and sheep produce an enzyme in their rumen that can separate the phosphorous and iron from the phytate. Therefore, humans should limit their intake of phytate as it interferes with the absorption of calcium, iron, and zinc.

The amount of phytate in grains can be reduced by soaking the food in acid medium. Legumes such as beans can be soaked overnight in very warm water to reduce their phytate content. Iver, et al (1980) showed that after 18 hours of soaking in warm water, great northern beans maintained 30% of their original phytic acid content, pinto beans 47% and kidney beans 48%. This method was more effective than simply cooking or germinating the beans.

In animal feed, Jan Pen, et al. (1993) have engineered transgenic seeds as a novel feed additive for improved phosphorous utilization. They have engineered phytase from Aspergillus niger in tobacco seeds, providing a stable and convenient packaging of the enzyme. The phytase enzyme helps release phosphorous from phytate. Taewan Kim, et al. (2005) have also attempted shifting the pH profile of the Aspergillus niger phytase in order to enhance its effectiveness inside the stomach as an animal feed additive. They were successful in shifting the pH optimum of one mutant to pH 3.8 demonstrating that it is feasible to improve the function of phytase under stomach pH conditions by rational protein engineering.

The northwestern iGEM team 2012 attempts to clone three phytase genes (Aspergillus niger, Citrobacter braakii, and Escherichia Coli) with constitutive promoters of varying strengths. We aim to use our cloned phytase gene as a probiotic for third world countries suffering from iron deficiency. The idea is that we can eventually distribute phytase containing E. Coli to different parts of the developing country so that they can utilize it into their staple food source. This is much more cost-effective than sending iron supplements as it can continually grow once it is in the food source.

Sources:

1. http://www.who.int/nutrition/topics/ida/en/index.html
2. http://jn.nutrition.org/content/138/12/2523.full
3. http://www.ncbi.nlm.nih.gov/pubmed/11943635
4. http://www.rebuild-from-depression.com/soaking-beans/
5. http://www.nature.com/nbt/journal/v11/n7/abs/nbt0793-811.html
6. http://aem.asm.org/content/72/6/4397.short