Biofuel, like many alternative energy sources that are on the rise, faces its share of criticism. While it sounds ideal to create fuel from plants rather than limited fossil fuels, many methods of producing biofuel come at a high environmental cost all their own. Land used for biofuel production, for example, could be better put to use growing consumable crops instead of “sustainable” power for our cars.
Although biofuels from wood or grass may have a better future than less sustainable sources like corn, they are much more difficult to produce. The first step in turning biomass from grasses, trees, and certain algae into biofuel is getting through lignin, the tough material of their cell walls, and the compound isn’t an easy one to break down.
However there are some bacteria that digest lignin quite well, and harnessing the chomping power of these microorganisms could eventually lead to easier and more sustainable biofuel creation. While researchers at Mississippi State University had focused on identifying the digestive bacteria in panda poop, researchers at Brown University are also studying microorganisms that can break down lignin--and have figured out the chemical switch to start the lignin digestive process in the bacteria Streptomyces.
One of the few microorganisms that can consume lignin, Streptomyces begins the digestion process by releasing enzymes to break lignin down into its constituent compounds. This lignin-derived carbon, which the bacteria uses for growth and reproduction, is also where the magic begins for biofuel production: Streptomyces converts some of it into triglycerides, essential components of biodiesel, as well as other useful compounds. The Brown researchers’ previous work showed which genes encode enzymes to break down one particular compound: protocatechuate. When Streptomyces was grown where protocatechuate was present, PcaV, a protein usually attached to the DNA that stops those genes clusters from encoding, lost its affinity for DNA--and those unblocked genes gave the green light for enzyme production.
While being able to kickstart the lignin digestion process could lead to an easier transformation of woody biomass into biofuel, producing biofuel through Streptomyces on a commercial scale is still a long way away. Nevertheless, this research is a step forward for bacteriology as well as sustainable bioenergy.
Image via Sello lab/Brown University
written by Tonny, April 08, 2013
written by Biodegradable Packaging, April 13, 2013
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