Researchers including one of Indian origin from the US Department of Energy's Berkeley Lab have engineered a strain of bacteria that enables a "one-pot" method for producing advanced biofuels from a slurry of pre-treated plant material.
The Escherichia coli (E coli) is able to tolerate the liquid salt used to break apart plant biomass into sugary polymers.
Developing ionic-liquid-tolerant bacteria eliminates the need to wash away the residual ionic liquid.
The achievement is a critical step in making biofuels a viable competitor to fossil fuels because it helps streamline the production process.
Being able to put everything together at one point, walk away, come back and then get your fuel, is a necessary step in moving forward with a biofuel economy," said principal investigator Aindrila Mukhopadhyay, vice president of the fuels' synthesis division at the Joint BioEnergy Institute (JBEI), Berkeley Lab.
"The E coli we've developed gets us closer to that goal. It is like a chassis that we build other things onto, like the chassis of a car. It can be used to integrate multiple recent technologies to convert a renewable carbon source like switchgrass to an advanced jet fuel," he added.
The basic steps of biofuel production start with deconstructing, or taking apart, the cellulose, hemicellulose and lignin that are bound together in the complex plant structure.
Enzymes are then added to release the sugars from that gooey mixture of cellulose and hemicellulose, a step called saccharification.
Bacteria can then take that sugar and churn out the desired biofuel.
The multiple steps are all done in separate pots.
Researchers pioneered the use of ionic liquids - salts that are liquid at room temperature - to tackle the deconstruction of plant material because of the efficiency with which the solvent works.
E. coli remains the workhorse microbial host in synthetic biology and in the new study, using the ionic-liquid-tolerant E. coli strain, we can combine many earlier discoveries to create an advanced biofuel in a single pot," the authors noted.
"Ultimately, we hope to develop processes that are robust and simple where one can directly convert any renewable plant material to a final fuel in a single pot," Mukhopadhyay noted in a paper published in the journal Green Chemistry.
--IANS
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