While some researchers turn to algae or grasses, others are turning their attention to bacteria as potential biofuel sources. Bacteria perform functions that produce byproducts like ethanol and hydrogen, says Umair Irfan at ClimateWire. Bacterial cells can also be used as biodiesel precursors, Irfan adds. The US Department of Energy's Joint BioEnergy Institute is working on ways to control these processes in bacteria using RNA. "Using computer simulations, James Carothers and his colleagues at JBEI have sped up the RNA design phase, creating computer tools that will help researchers design molecules to precisely control gene expression in bacteria to optimize fuel production," Irfan says. "The team studied the bacterium Escherichia coli as a model organism, comparing how 28 RNA sequences behaved in their model and in the microbe. They found that their computer predictions accurately agreed with how the bacteria responded to the control system." Eventually, the researchers would like to design RNA and insert them into the bacteria, rather than trying to use the organisms' existing RNA. "Using these tools, Carothers expects that bacteria can renewably produce hydrocarbons already in use today, like diesel and jet fuel, creating 'drop-in' replacements for fossil energy," Irfan adds.