Team:Charlottesville RS/Project

Project Idea

Junk Food

In Albemarle County, most of the waste water goes and is processed through the Moores Creek Wastewater Treatment Plant (WWTP), which is managed by the Rivanna Water & Sewer Authority. Each year, the plant purchases 250,000 dollars worth of glycerin, which is then used as “food” for bacteria which degrade the other organic matter in the water.

The UVA iGEM team from 2008 created a part that, when added, enables E Coli to produce polyhydroxybutyrate, a biodegradable, bio-derived plastic. Our idea is to make a type of E Coli that produces this plastic, with a reporter which fluoresces when the bacteria is successfully producing.

The plant could then use this bacteria to create polyhydroxybutyrate, filter out the E Coli, and then use the plastic as an alternative food source for their bacteria, saving them 250,000 dollars per year, as well as giving them a renewable energy source for their plant.

Importance of Nitrogen

Nitrogen is essential for all living things: animals and plants. Nitrogen forms a part of the proteins and DNA that are found in cells. Animals get nitrogen by eating plants and other animals. Just like animals, plants require nitrogen to grow and survive. But they do not get nitrogen by consuming proteins like animals do. Plants get nitrogen from water and from the soil. They get nitrogen by absorbing it in the form of nitrates and ammonium. Nitrates are the major source of nitrogen for aquatic plants. Nitrates are not utilized by aquatic organisms such as fish and aquatic insects, but nitrates are used by aquatic plants.

NO3

Nitrate (NO3) is a compound found in most water. It is colorless and odorless, so can only be detected with testing. Nitrate itself isn’t bad in water, but it causes eutrophic effects if there is too much, which causes a chain reaction of harmful effects. Every living organism needs nitrogen to live; it forms part of the protein in DNA and other cells that are essential for plants and animals. Animals (like ourselves) get nitrogen from eating plants and other animals. Plants get nitrogen not by consuming other organisms but by absorbing it through the soil - in the form of ammonia and nitrates (which are the main source of nitrogen for aquatic plants).

Why nitrates are bad in drinking water

High nitrate levels in water can cause methemoglobinemia or blue baby syndrome, a condition found especially in infants under six months. The stomach acid of an infant is not as strong as in older children and adults. This causes an increase in bacteria that can readily convert nitrate to nitrite (NO2). Do not let infants drink water that exceeds 10 mg/l NO3-N. This includes formula preparation. Nitrite is absorbed in the blood, and hemoglobin (the oxygen-carrying component of blood) is converted to methemoglobin. Methemoglobin does not carry oxygen efficiently. This results in a reduced oxygen supply to vital tissues such as the brain. Methemoglobin in infant blood cannot change back to hemoglobin, which normally occurs in adults. Severe methemoglobinemia can result in brain damage and death. Pregnant women, adults with reduced stomach acidity, and people deficient in the enzyme that changes methemoglobin back to normal hemoglobin are all susceptible to nitrite-induced methemoglobinemia. The most obvious symptom of methemoglobinemia is a bluish color of the skin, particularly around the eyes and mouth. Other symptoms include headache, dizziness, weakness or difficulty in breathing. Take babies with the above symptoms to the hospital emergency room immediately. If recognized in time, methemoglobinemia is treated easily with an injection of methylene blue. Healthy adults can consume fairly large amounts of nitrate with few known health effects. In fact, most of the nitrate we consume is from our diets, particularly from raw or cooked vegetables. This nitrate is readily absorbed and excreted in the urine. However, prolonged intake of high levels of nitrate are linked to gastric problems due to the formations of nitrosamines. N-nitrosamine compounds have been shown to cause cancer in test animals. Studies of people exposed to high levels of nitrate or nitrite have not provided convincing evidence of an increased risk of cancer.

Polyhydroxybutyrate

Polyhydroxybutyrate (PHB) is a polymer of glucose and starch and a biodegradable plastic. It is a special type of polyester called a polyhydroxyalkanoate. PHB is produced by microorganisms such as Ralstonia eutrophus or Bacillus megaterium in response to conditions of physiological stress, particularly conditions in which nutrients are limited. PHB can also serve as food for other bacteria.

In waste water treatment, bacteria are required to dispose of waste in the water, but feeding them is very expensive for treatment plans, and for the Rivanna Water Treatment Plant, the closest such facility to our school, it costs the city up to $250,000 a month to simply feed these bacteria.

Our idea for the project involves using bacteria such as Ralstonia eutrophus or Bacillus megaterium in order to produce PHB as food for the bacteria that are involved in waste water treatment. Since PHB is only produced when nutrients are limited, it would actually involve feeding the PHB-producing bacteria less than the waste water treatment bacteria would be fed. We believe our idea has the potential to drastically reduce the costs of waste water treatment plants around the globe.