Question: Could bacteria be used to reduce waste?

Rhodri Jenkins answered on 15 Jun 2013:

This is an incredibly insightful question – thanks for asking it!

Now, what I suppose you mean from this questions is can we feed bacteria waste to get useful stuff out. In theory, yes. There’s bacteria that exist in the guy of cows which feed on the stuff in a cows digestive system … and make “biogas”, which is a mixture of methane and carbon dioxide. Methane is one of the main components of natural gas, a fossil fuel. So if we can take this bacteria, feed it waste material, we have a method of producing renewable natural gas. This is being carried out in a lot of countries and we use biogas to power certain things. The reason it’s not more wide-spread is because the specific bacteria need a specific type of waste (cow manure) to grow, which we don’t quite have enough of. If we can change the bacteria to take any old waste that would be great.

Apart from bacteria, though, there are loads of different types of microbes which could be used to reduce waste and make useful products. In our group we look at yeast … such as the yeast we use to make beer and bread. Feeding yeast sugars and starches such as the stuff you find in food (and food waste) … it can either produce useful molecules, or possibly to produce liquid fuels with improved properties. However, every yeast needs a specific food to grow on … so some of the work we’re trying to do is find out exactly what we can get away with feeding them. Ideally we’d like to feed them with resources we have a lot of, and that don’t compete with food. Such as wood, or grasses that grow on land we wouldn’t be able to use for food.

So in a shorter answer to your question … yes. We could use bacteria (as well as other microbes) to reduce waste. We just have to find the right ones (or alter the ones we have) to suit the waste we have.