Putting microbes to work

Microbes are great at making products we use in our everyday life. We’ve been putting them to work for thousands of years making beer, wine and bread for example, but are we using them to their full potential? As well as making ethanol via yeast fermentation, microbes can also be coaxed into overproducing a whole load of other useful molecules. Staying with food, some are great at producing amino acids such as glutamate used as mono-sodium glutamate or MSG in your food. The next time you have a Chinese meal consider that it was microbes that contributed that umami flavour to your food. And this is big business too - nearly 500,000 tonnes of glutamate are made by microbes each year.

Another type of product which is really important to man are antibiotics. While penicillin is made by a fungus, many more of the antibiotics we use in medicine are made by bacteria, in particular the Actinobacteria, which you can see more about in the article. To try and make these bacteria produce more antibiotic we have many tools at our disposal. In York we teach our students all these methods to understand how the bacterial DNA can be read, interpreted and then manipulated to make the bugs do more work for us.

Scientists in my research group are working hard on engineering bacteria to become better at producing fuels and chemicals and our undergraduate and masters students get to help us too, which is incredibly valuable. Growing microbes in the lab is one thing, but at large scale it is a science in itself - biochemical engineering in fact. These industrial scale fermentations require specialised tanks that can contains tens of thousands of litres of growth media where the bacteria can be grown and held at the right conditions that are maximal for producing the product. Then they need to be harvested and the product purified, all of which required good understanding of the bugs themselves and the chemical properties of the molecule being produced.

So why are microbes so good at all this? This mainly relates to their size and ease of growth. Microbes can grow very quickly and many are not too fussy about what they eat. They can be thrown around inside the massive fermenter and not bat an eyelid and their small size means that they have a high surface to volume ratio that means its relatively easy to get food in and products out quickly. They are excellent cell factories. However, at the moment microbes can’t make everything and there are major challenges to engineer them to make more complex products like antibodies.

Using advanced genetic engineering and synthetic biology to get more work out of microbe is the challenges for future generations of microbial engineers - perhaps that might be you?