Bioengineered bacteria could produce fuel from CO2
By Ben Coxworth
August 27, 2012
Scientists at the Massachusetts Institute of Technology (MIT) have succeeded in genetically altering Ralstonia eutropha soil bacteria in such a way that they are able to convert carbon into isobutanol, an alcohol that can be blended with or even substituted for gasoline. It is hoped that once developed further, this technology could help reduce our reliance on fossil fuels, and lessen the amount of carbon dioxide released into the atmosphere by smoke stacks.
When their regular carbon food sources become scarce, R. eutropha ordinarily respond by synthesizing a type of polymer, in which they store whatever carbon they’re able to find. By “knocking out a few genes, inserting a gene from another organism and tinkering with the expression of other genes,” the team of MIT biologists were able to get the bacteria to produce isobutanol instead of that polymer.
Unlike certain other biofuels, isobutanol can be used directly as is, requiring no refining. The bacteria produce the alcohol continuously, releasing it into their fluid environment, from which it can be filtered. This differs from experiments conducted at other institutions, in which various types of bacteria have had to be destroyed in order to harvest the desired biofuel byproducts from their bodies.
Currently, the genetically modified microbes are getting their carbon from fructose. It is expected that with further alterations, however, they should be able to draw it from industrial carbon dioxide gas emissions. In fact, the scientists believe that properly bioengineered R. eutropha should be able to feed on carbon from almost any source, such as agricultural or municipal waste.
The team is now looking into increasing the bacteria’s isobutanol production levels, and scaling the technology up for use in industrial-scale bioreactors. If successful, such facilities should lessen the need for biofuel-dedicated crops such as corn, that compete with food crops for land and water.
In fact, MIT isn’t the first place to experience success in this area of research. In 2009, scientists from UCLA announced that they had been able to harvest isobutanol from CO2-consuming Synechoccus elongatus bacteria.
A paper on the Massachusetts research was published this month in the journal Applied Microbiology and Biotechnology.