One More Benefit of Biofuels: Newfound Use For The Byproduct, Crude Glycerol
While biofuel is an exciting improvement in the war on CO2 emissions, one drawback is that the manufacturing of plant-based fuels also involves the production of a nasty byproduct - crude glycerol (aka glycerine). Crude glycerol is a particularly viscous substance, notorious for being difficult and expensive to dispose of. Glycerol can be found in hundreds of food products, pharmaceuticals, and soaps; however, the glycerol produced by biofuel manufacturing isn't pure enough for reuse in these items. And while it can be purified, that of course would cost too much. To give you an idea of the severity of this drawback, consider that for every million gallons of biodiesel produced, about 100,000 gallons of crude glycerol are also produced.
Thankfully, a graduate student from the University of Alabama Huntsville has identified a bacteria that just adores glycerol. Clostridium pasteuranium is a bacteria that naturally occurs in soil and is known for its ability to fix nitrogen in the air. Interestingly, when this little bugger digests glycerol, Keerthi Venkataramanan, who is closely studying the bacteria, found that it generates at least 5 valuable byproducts including acetic acid and butyric acid as well as three alcohol byproducts that can be used for fuel: propanediol, ethanol, and butanol, a particularly promising substitute for gasoline. Butanol is even more valuable than ethanol because it is a four-carbon molecule - twice as big as ethanol. According to Venkataramanan, butanol can be used as an industry solvent as well as fuel for cars without modification. Butanol also has the added benefit of a slower evaporation rate.
The hope is that more efficient strains of the bacteria can be developed so the glycerol produced by biofuel production can be put to good use, especially when you consider that America alone produced up to 500,000 gallons of crude glycerol as a result of biodiesel production, and Europe produced much more. As it stands, clostridium pasteuranium can convert approximately 30-35 percent of glycerol into butanol but improvements are being researched.
What's more, other solutions for crude glycerol are being researched. Researchers from Rice University are studying clostridium pasteuranium with the aim to make the glycerol-eating process more efficient. Elsewhere, researchers are looking to simply develop alternative uses for crude glycerol such as growing micro-algae, producing methane, using it for cattle feed, or manufacturing a non-toxic antifreeze.
This research is rather exciting because when improperly disposed of, crude glycerol can pollute groundwater and waterways, thus killing wildlife. And since biofuel production is on the rise, this new research is especially needed now. Perhaps one day the nasty byproduct, crude glycerol, will no longer be considered a drawback, rather an added benefit of biofuel production.