Saturday, December 1, 2012

Bacteria for the Environment

I am a biochemist and microbiologist. As the latter, I have mainly been involved with bacteria and fungi that cause disease. For some years, I have been increasingly interested in how micro-organisms can be used for the environment. My enthusiastic self exclaims to anyone who will listen "There are bugs out there that can metabolise anything!". Really? Anything? This sounds just a little wooly. What can these organisms really do for the environment and how do they do it for themselves and for us? What are the pros and cons? Are they really a solution to our oil addiction?

This blog is an exploratory journey for me, to satisfy my own curiosity and anyone else who cares to read it; this first post is introductory, to see what the very general fields are in terms of bacteria. And I do mean bacteria, but I hope to delve into fungi and algae along the way. In the following installments, there will be more references and research. I aim to present facts as accurately as possible while not getting too serious. For now I'll just raise some questions  - come back to find out the answers!

Bacteria eat our waste.
Artwork: Mark W.  Slate (
We all know that bacteria and fungi are the engines of composting. If you make your compost rich and warm then the degradation goes that much faster. Make your compost pile out in the open and the microorganism will work their magic, but perhaps they'll be a little slower. They will take care of all the organic waste - paper, food scraps, fecal matter, plant waste, man-made biodegradeable items etc. There seems to be more awareness of the need for composting to reduce what we put in our landfills and to save resources, with communities turning to industrial composting but how wide spread is this?

Its not only organic matter that bacteria can degrade. They can also use “unnatural” materials like plastics, organic solvents and heavy metal contaminants as a resource though sometimes we have to help them along, either by engineering their genomes or by providing an optimal environment.

As bacteria live everywhere, degradation of waste doesn't only happen in soil, it goes on in water too.  One of most disturbing aspects of our modern life are the great swirls of plastic debris pooling in the Sargasso Sea in the North Atlantic Ocean, driven there by currents. The plastic is ground down as stones are ground down to sand and floats as a layer of microscopic debris beneath the surface of the ocean. Bacteria are able to breakdown these microscopic particles, slowing down the increase in size of the pool of plastic.Without human intervention, are bacteria helping to clean up the oceans?

So could this be a magic bullet?  All we need to do is add a load of bacteria on to some contaminated land or a mound of empty water bottles and Abracadabra! a nice pile of nutrient rich sludge is made to use on the field for next year’s crop? Unfortunately and predictably, it is not so easy. Many bacteria are rather finicky in their growth conditions and while you can produce great results in the optimal conditions of the lab, once you put your industrious devourers into a more natural environment where there are lower levels of nutrients and competing, better adapted bacteria, sucking up those nutrients and releasing antibiotics to fight off any newcomers, life becomes much more of a challenge.  And then there is the issue of bacterial waste. Once the molecules of plastic are broken down in the sea or in the soil or even in the lab, what do they become; something nice and safe or something more toxic than the initial product? For example do the bacteria eating plastic in the Sargasso Sea produce toxins that end up in fish and then migrate up the food chain to us?

Bacteria produce plastics, fuel
I’ve just devoted a couple of paragraphs to how bacteria degrade plastic but actually, they can also be used as tiny manufacturing plants. It seems a great deal to ask that they make what we are hoping they will break down. However, bacteria can and are being engineered to produce plastic and fuels. Some bacteria even secrete organic solvents so that all you need to do is to centrifuge away the bacteria and suck off the secreted products layered on top. There is even research into getting bacteria to produce electricity!

BUT we humans need alot of fuel and alot of plastic - a gigantic amount if you compare it to the size of a bacterium or even a few million bacteria. Can we have really have our cake and eat it too? How close are we to producing plastic or fuel from bacteria on a scale that would supply our demand? And yes, there are some small and not so small bumps in the road to circumnavigate. What do you feed the bacteria? Plastics??? What do you do with the bacterial waste products? Bacteria are living organisms with finite life spans. How do you remove the dead cells? To keep costs down and production up, optimal conditions must be established and maintained and this requires a good deal of experimentation and optimization, first on a laboratory scale and then on an industrial scale.

I hope that wets your appetite for the next installment which should be published on November 30th - tentatively titled "Bacterial degradation of plastic - part 1".