There are bacteria that bleed? Bacteria-enhanced ethanol production

Researchers: Ben Stark, Illinois Institute of Technology, and Meltem Akbas, Gebze Institute of Technology (Turkey)

Researchers at the Illinois Institute of Technology have discovered a unique method to increasing bioethanol production using a special oxygen-scavenging bacterium. This could prove promising for the scale-up of biofuels, which are far less efficient to produce than traditional oil and gas.

The bacterium, called Vitreoscilla, contains hemoglobin, a molecule found mostly in the blood of vertebrates and used for transporting oxygen. The researchers harnessed the oxygen transport abilities of Vitreoscilla hemoglobin to boost the fermentation process in producing bioethanol.

Vitreoscilla is this bacterium that is also like us – aerobic. It can’t live without oxygen. But, it lives in these environments where there isn’t very much oxygen,” said Benjamin Stark, principle investigator and biologist at IIT. To adapt, the bacterium developed this type of hemoglobin with immense oxygen-scavenging abilities. This allowed it to take advantage of environments that other organisms couldn’t survive in.

As it turns out, this oxygen-scavenging ability can be channeled into bumping up bioethanol production. In Stark’s research, the hemoglobin gene is used to increase ethanol production from corn stover.

The hemoglobin gene is isolated and inserted into a strain of E. coli bacteria, which is added to hydrolyzed corn stover, which is corn stover degraded in preparation for ethanol production. The hemoglobin gene causes the E. coli to uptake oxygen much more efficiently, which speeds up fermentation of the corn stover and produces more ethanol.

Stark’s lab at IIT is a center of Vitreoscilla hemoglobin research worldwide. Meltem Akbas, biologist at Gebze Institute of Technology in Gebze, Turkey, travels most summers to IIT to work on Vitreoscilla with Stark.

At present the focus of the research is to find the best waste material to use for ethanol production, Akbas said. Potato waste produces more ethanol with Vitreoscilla hemoglobin than corn stover, but other waste materials may be even more efficient. Growth conditions can also be optimized to increase production.

If successful, the research could be used to support large-scale production of bioethanol, lowering costs and making it a more viable alternative to traditional oil and gas. Ethanol comprised just 10 percent of U.S. gasoline usage for transportation as of 2011.

Vitreoscilla hemoglobin was first discovered by Dale Webster at IIT in the 1980’s, which has touched off the field of bacterial hemoglobin research since.


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