Search for biofuels leads to the human gut

The search for microorganisms to use in biofuel generation has led to the human lower intestine. A new study demonstrates how such microorganisms could be effective candidates for organic fuel production.

Scientists have demonstrated that bacteria in the human digestive system can digest fiber, and, in the process, break down fiber into simple sugars. Using applied thinking, these same sugars can be fed to yeast to generate ethanol and other candidate biofuels. The human gut bacteria appear especially rich in enzymes that can break down complex plant fibers more efficiently than other microbes identified to date.

Biofuels include fuels derived from biomass conversion. One key source of biomass is plants.

Such a biomass can be used as a feedstock for ethanol production, with ethanol either used as a fuel for vehicles in its pure form, or used as a gasoline additive to increase octane and improve vehicle emissions. Many cars on the road can run on blends of up to ten percent ethanol. Today ethanol represents around ten percent of the U.S. gasoline fuel supply derived from domestic sources, according to the Renewable Fuels Association.

To create ethanol yeasts are used to make sugars; however, a pre-step is required to turn plants into sugars. This is where the bacteria come in. With bacteria, researchers have identified two good contenders from the human gut: human microbes, Bacteroides intestinalis and Bacteroides ovatus.

The findings have been published in Proceedings of the National Academy of Sciences, in a paper titled “Xylan utilization in human gut commensal bacteria is orchestrated by unique modular organization of polysaccharide-degrading enzymes.”