Bacteria gets a bad rap. Sure, certain harmful strains such as E. coli and staph occasionally reek havoc in our food chain and hospitals, but overall these potent unicellular microorganisms help more than they harm -- and are the secret ingredient of certain budding green technologies.
As Discovery News' Alyssa Danigelis reports, scientists worldwide are working on ways to put bacteria to work in recycling plastics. One of the biggest problems with current plastic recycling methods is that the only possible end result is polyethylene terephthalate, a relatively low-grade material that isn't as desired or useful as other plastics like PHA.
Microbiologist Kevin O'Connor and his team came up with a process that sounds a little like alchemy at first, but should work. O'Connor's group heated PET to break it down into a gas, a liquid, and a solid. From there, they grabbed a particular strain of bacteria that was partial to the plastic at a local bottling plant in Dublin. Sure enough, the bacteria took a liking to O'Connor's snack and turned the solid into PHA. The other byproducts will be burned as a heat source to make more of the stuff. While it won't outright solve our plastic problems, this process should encourage more recycling and open up new markets.
Easing Ethanol Production
Similarly, Matthew McDermott recently blogged on Treehugger about how thermophilic bacteria can be used to produce cellulosic ethanol -- which is the biofuel you already hear so much about, but without using food sources.
As Chris Ayres described this summer in the Times of London, bacteria also can be tapped directly as an alternative energy source. Scientists in Silicon Valley are currently experimenting with bacteria that have been genetically altered to excrete what is being termed 'renewable petroleum'.
Because crude oil (which can be refined into other products, such as petroleum or jet fuel) is only a few molecular stages removed from the fatty acids normally excreted by yeast or E. coli during fermentation, it does not take much fiddling to get the desired result.
Using genetically modified bugs for fermentation is essentially the same as using natural bacteria to produce ethanol, although the energy-intensive final process of distillation is virtually eliminated because the bugs excrete a substance that is almost pump-ready.
Identifying Harmful Chemicals
Not only has bacteria begun to play an essential role in the development of alternative energy sources, but it also proves useful in identifying harmful pollutants. For example, living bacteria are modified to glow when they detect certain chemicals, a technique that could allow for more rapid and less expensive testing of pollutants. Jocelyn Rice recently explained the phenomenon in MIT's Technology Review:
Last spring, on a research vessel cruising through the North Sea, Swiss scientists examined tiny vials of bacteria mixed with seawater for hints of fluorescent light. By analyzing how brightly the bacteria glowed, and with which colors, they were able to diagnose and characterize the early aftermath of an oil spill.
"The extreme simplicity of this is that the heart of the sensor is the bacterial cell, and that the cell is a multiplying entity," says Van der Meer. "It's extremely simple to reproduce them, and then you have enough for thousands of tests."
Although bacteria is typically considered a contaminant, it can be used to purify water by feeding on organic waste material. Chris O'Brien of Fermenting Revolution explains how progressive breweries have begun to employ this technology as a means of decreasing their impact on their local water processing plants. The process is also a great producer of methane gas, which can be harnessed and channeled back to the production line.
Brewers can reduce treatment fees by operating their own wastewater treatment plants. In fact, Coors designed and built the first modern wastewater treatment plant in Colorado in 1952, adding a secondary treatment process decades before it was required to do so. But treatment still requires large amounts of electricity and energy. It may save the tax-payer a little bit of money (or it might not) but either way it doesn't do much to reduce water usage. However, some breweries are using anaerobic digesters to clean their water and reduce the need for conventional treatment options. As a result, they also recover energy through the generation of biogas.
Bacteria will almost certainly outlive us, but in the meanwhile it continues to contribute to our well-being, enhance our lifestyles by providing us with various fermented delicacies like beer, and play a key role in our attempts to stem climate change.
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