Team:Johns Hopkins/Vit/Bg

Background

Vitamin A deficiency is a public health problem affecting more than half of all countries, most notably in Africa and South Asia. It especially affects young children and pregnant women in low-income countries. The numbers associated with this problem are staggering - 250,000,000 preschool children are Vitamin A deficient, and every year, 250,000 to 500,000 of these children become blind. Over half of them die within 12 months of the onset of blindness. It is also a major cause of maternal mortality. Another major cause of malnutrition in developing nations is Vitamin C deficiency. It is most prevalent in South Asia, in the countries of India and Pakistan. The root of the problem lies in the lack of awareness and availablity of the required foods that constitute proper diet. These commodities are generally much more expensive than staples like grain. As a result, malnutrition is very prominent in these developing countries.

We aim to combat this tragic and preventable loss of life by designing a strain of yeast that can produce a Vitamin A precursor, beta-carotene, that our body can convert into Vitamin A in large enough quantities so that it meets the daily required amounts. We also aim to install a Vitamin C biosynthesis pathway in yeast that can be introduced into staples that people eat and drink, such as bread and beer, at no extra cost, as yeast are already used in these processes.

An important aspect of the VitaYeast project is to be able to regulate the amount of β-carotene and Vitamin C in our final food products. As overexpressing the enzymes in our pathways to a great degree would over-stress our yeast, we need to be able to optimally regulate the amount of each vitamin in order to maintain viable yeast that is maximally beneficial to the consumer. Therefore, it is crucial to have a system by which we can measure baseline kinetic rates of enzymes and substrates/products in the cell, make modifications to our system, and measure their impact accordingly. These quantitative experiments would prove to be crucial for optimizing our yeast strains and producing maximally efficient, vitamin-producing bread.