Say Hello to Two New Microbial Employees

Give them a cozy place to live and plenty of food, and they will make fuel and chemicals without demanding a salary or a pension. They’re microbes – and just like with any workers, it’s important to find good ones to make a business successful.

Two new kinds of microbes may be putting on hard hats and punching time clocks in the renewable fuels and chemicals space, thanks to researchers working on separate projects at the University of Georgia and MIT.

University of Georgia scientist Janet Westpheling, a microbial geneticist in the Department of Genetics, and her colleagues have developed an enzyme tool to alter the DNA of a group of thermophilic anaerobic bacteria called Caldicellulosiruptor. These bacteria can munch on biomass directly, which make them interesting for streamlining the process for producing useful products from biomass.

According to UGa, the newly developed process means researchers can redesign Caldicellulosiruptor to make useful stuff like ethanol or polymers. It remains to be seen, of course, how well the modified bacteria do compared to the established competition (heat, enzyme and/or acid treatment followed by fermentation by yeast) to make ethanol from cellulosic feedstocks. If the microbes can withstand real-world processing conditions and cut out some steps, they may find job security.

Meanwhile, at MIT, researchers are busy stressing out a soil bacterium called Ralstonia eutropha in an effort to prepare it for a job making isobutanol. Christopher Brigham, in MIT’s biology department and his team know that when Ralstonia is deprived of nutrients such as nitrate or phosphate, it starts storing carbon in complex compounds, perhaps in order to store food for later. By engineering it to change the type of compound, Ralstonia could make fuel from carbon inputs such as CO2.

The modified bacteria would expel the compound – in this case isobutanol – in a continuous process that could be scaled up. This tends to sound favorable compared to normal batch processes. In the lab, Brigham’s group has been feeding the microbe fructose, but the focus is now on switching to CO2 as a feedstock.

Author: Melody Bomgardner

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