Keerthi Venkataramanan, glycerol eating bacteria, biofuel, biofuel waste, useful bacteria
Photo credit: UAHuntsville

Biofuels are clearly superior to petroleum products when it comes to being eco-friendly and reducing greenhouse gas emissions, but the manufacturing of plant based fuels results in a byproduct of crude glycerol. The viscous substance is notoriously hard to dispose of but a graduate student at the University of Alabama Huntsville discovered that a strain of bacteria could help mitigate the problem by consuming the glycerol to create products that can be used as energy sources.

For every million gallons of biodiesel created, about 100,000 gallons of glyercol are produced. That may not sound like much, but when you consider that in 2009, America produced 500 million gallons of biodiesel and Europe produced 2.75 billion, it adds up. Pure glycerol is used in soaps and pharmaceuticals, but the crude form left over from biofuel production would be way too expensive to purify.

Keerthi Venkataramanan, glycerol eating bacteria, biofuel, biofuel waste, useful bacteria
Credit: Nestle Oil

The bacteria, Clostidium pasteurianum, is found deep in the soil and is known for its abilities to fix nitrogen in the air. Keerthi Venkataramanan is studying the bacteria, and found that eats crude glycerol and generates acetic acid and butyric acid, two common acids found in food, and, most importantly, three alcohol byproducts that can be used for fuel — butanol, propanediol, and ethanol. Of the three, butanol is the most interesting and has the most potential.

While ethanol has a long history as being used for fuel, butanol does not. Butanol is a four-carbon molecule twice as big as two-carbon ehtanol, which means that it has a much higher energy value. Venkataramanan explained to Environmental Protection that it can be used as an industry solvent, and as fuel for cars the exact same way that ethanol is used — no modifications necessary. Other benefits include a slower rate of evaporation.

Currently, the bacteria convert about 30 to 35 percent of their glycerol intake into butanol, but Venkataramanan is experimenting with different strategies to improve the yield, while also studying ways to develop a more productive strand.


When crude glycerol is improperly disposed, it can pollute groundwater and waterways, killing fish. With biofuel production continuing to rise, more and more glycerol will be created as a result. By converting it into useful products, we can avoid unnecessary waste and pollution.

Via Clean Technica