Team:Charlottesville RS/Project

Project Idea

Junk Food

In Albemarle County, most of the waste water goes and is processed through the Moore's 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

Nitrate (NO3) is a compound found in most water. It is colorless and odorless, so it 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 (explained further in the next section). Every living organism (as well as non-living organisms such as viruses) needs nitrogen to live; it helps to form the structure of proteins and DNA and many other molecules in cells that are essential for plants and animals to live. The majority of nitrogen in the world is held in the atmosphere, but not in its usable form. For nitrogen to be usable by organisms, it must be in the form of either ammonium or nitrate, which it is converted to in either abiotic or biotic fixation. 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 its fixated forms.

Why we Don't Want Nitrates in our Water

Because everything needs nitrogen to live, we obviously want to have some in our water. The problem arises when there is just too much - because that causes eutrophication. This is a huge problem right now in the Chesapeake Bay, and since we are part of the watershed that flows into the Bay, we have a responsibility to keep it clean. The Moores Creek WWTP and other treatment plants in the area are now obligated under the law to filter enough nitrate out of the sewage water because of the condition of the Chesapeake Bay, but soon most treatment plants in the country will probably have to follow in their footsteps. The filtered supernatant of the sewage water that goes through Moores Creek will drain into the Bay, so it needs to be clean. If there is too much nitrate in this supernatant, it will further contribute to the decline of the Bay - when there is too much of a macronutrient like nitrate, everything grows too much. For our purposes, this is mostly bad in reference to algae. The huge algae blooms that eutrophication causes not only block out sunlight to the organisms living under the water, but they eventually lead to anoxic zones in the water (meaning that there is no oxygen there). This happens when the algae dies and floats to the bottom of the water, and is then eaten by bacteria. Because there is so much algae to eat, the bacteria community flourishes, and they end up using all the oxygen in the water. Animals like fish and any others that preform cellular respiration cannot live under these circumstances because they need oxygen - this often leads to large groups of organisms dying. Right now, eutrophication is probably the biggest problem for the Chesapeake Bay, and plenty of other bodies of water in the world, It's very important that waste water treatment plants do their job efficiently and without too much money spent; and using polyhydroxybutyrate instead of glycerin will help to do that.

Polyhydroxybutyrate

Polyhydroxybutyrate (PHB) is a polymer of glucose 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 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.