About the author
Tessa Fiorini Cohen
Bacteria get a bad rap. They’re blamed for disease, rotting food, the stench that comes from stagnant water – and rightly so. But much less is said about their positive side and how they’re currently acting as microscopic soldiers in the quest towards a greener lifestyle. There are two sides to this story; bioprospecting and bioengineering.
Bacteria live everywhere; from the depths of an ocean, to the inside of a volcano, to the sides of the International Space Station. They are experts at not just surviving, but thriving, in harsh environments. And this is what makes them ideal candidates for green bioprospecting.
Bioprospecting involves hunting through nature, and using the creatures or systems discovered to develop products that are needed by man. For instance, Aspirin is a result of such bioprospecting and is based on a chemical that was found in the bark of the Willow Tree. In the case of bacteria and green chemistry, what bioprospectors are mainly interested in are bacterial enzymes. Enzymes are found within the bacterial cells, and function as their powerhouses. They speed up chemical reactions, and are responsible for keeping cells alive and functioning. As bacteria thrive in harsh environments, their enzymes do too. And depending on what specific function each enzyme performs, they can be put to use in a myriad of products familiar to us in our daily lives.
video: Biofuels and bioprospecting for beginners – Craig A. Kohn by Ted-Ed
One such success story are cold-wash detergents. Many clothes stains are protein and fat-based. Drop some mayonnaise on your jumper and you’ve basically stained it with a dollop of protein and fat. So to be effective, clothes detergents need to include chemicals that break down these substances. During search expeditions in the Arctic, bioprospectors discovered enzymes that break down proteins and fats at ice-cold temperatures. Fast-forward a few years, and these enzymes have already been commercialized – there are likely loads of these microscopic soldiers in the detergent that you currently use. They allow food stains to be washed off at room temperature, unlike older, chemical-based detergents that needed hotter temperatures to help the cleaning process. In this manner, associated energy use is reduced and eco-friendliness is improved. Similar uses have been extended to surfaces that need to be cleaned but cannot be heated, such as art and masonry restoration, as well as furniture.
Bacterial enzymes aren’t only found in final products, but are also used in the industrial processes that manufacture the products. Here, they also help to speed up chemical reactions, allowing them to take place in a more ecofriendly manner, using lower temperatures and pressures. Bacteria that thrive in highly acidic or alkali conditions, chemical solvents and elevated temperature and pressure environments are the holy grail in this case, as industrial reactions usually take place in similarly harsh environments. This is where those volcanic bacteria come in – more than fifty candidates have been identified from Iceland’s volcanoes alone. Many international projects are similarly focusing on such bioprospecting from a variety of hotspots.
The ocean floor has been estimated to contain ten million trillion microbes for every human on the planet. It’s a mindboggling amount and it’s just the ocean floor – let alone all the other habitats out there, such as glaciers, soil, and any other you may think of. Hunting through bacterial species in order to find one that performs the function desired can thus be an endless task. Thanks to new technologies, there is another route to the desired bacteria – engineering it to perform the green function required.
This engineering involves playing around with the bacterium’s DNA – inserting strands that code for the particular trait desired, into the bacterium’s original DNA. One such green success story is the use of bacteria to make rubber. This is a joint project by DuPont and GoodYear, and is known as BioIsopreneTM. Natural rubber is a limited resource, which is produced by only a few tree species. Due to this limitation, most commercial rubber is synthetic and manufactured from petroleum; a non-sustainable resource.
video: BioIsoprene Tyre: Genencor’s Karl Sanford explains collaboration with Goodyear by EurActiv
Through bioengineering, DNA from rubber-producing trees has been inserted into bacterial cells, enabling the bacteria to produce rubber. As bacteria multiply so quickly, millions can be put to work in large-scale manufacturing processes. This has provided a renewable source of rubber that reduces the demand for oil. Rubber manufactured in this manner can be used in car tyres, surgical gloves, adhesives and advanced transportation. Similarly, other kinds of engineered bacteria are also being used throughout the chemical industry to produce biofuels, acrylics, nylon and bioplastics. The old adage, that there are two sides to every coin seems to hold true for bacteria as well.