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futurity_sci_tech 00364.txt

#Extra-hairy microbes make biodiesel sustainable With the help of Geobacter microbes, biodiesel plants may be able to stop creating hazardous wastes and eliminate fossil fuel from their production process. The platform, which uses microbes to glean ethanol from glycerol and has added the benefit of cleaning up the wastewater, will allow producers to reincorporate the ethanol and the water into the fuel-making process, says Gemma Reguera, Michigan State university microbiologist and one of the study coauthors. ith a saturated glycerol market, traditional approaches see producers pay hefty fees to have hauled toxic wastewater off to treatment plants, she says. y cleaning the water with microbes on-site, wee come up with a way to allow producers to generate bioethanol, which replaces petrochemical methanol. At the same time, they are taking care of their hazardous waste problem. AIRYBACTERIA The results, which appear in the journal Environmental science and Technology, show that the key to Reguera platform is patented her adaptive-engineered bacteriaeobacter sulfurreducens. Geobacter are naturally occurring microbes that have proved promising in cleaning up nuclear waste as well in improving other biofuel processes. Much of Reguera research with these bacteria focuses on engineering their conductive pili or nanowires. These hairlike appendages are the managers of electrical activity during a cleanup and biofuel production. First Reguera, along with lead authors and graduate students Allison Speers and Jenna Young, evolved Geobacter to withstand increasing amounts of toxic glycerol. The next step, the team searched for partner bacteria that could ferment it into ethanol while generating byproducts that edthe Geobacter. FEASTING BACTERIA t took some tweaking, but we eventually developed a robust bacterium to pair with Geobacter, Reguera says. e matched them up like dance partners, modifying each of them to work seamlessly together and eliminate all of the waste. Together, the bacteria appetite for the toxic byproducts is inexhaustible. hey feast like theye at a Las vegas buffet she adds. ne bacterium ferments the glycerol waste to produce bioethanol, which can be reused to make biodiesel from oil feedstocks. Geobacter removes any waste produced during glycerol fermentation to generate electricity. It is a win-win situation. The hungry microbes are featured the component of Reguera microbial electrolysis cells, or MECS. These fuel cells do not harvest electricity as an output. Rather, they use a small electrical input platform to generate hydrogen and increase the MEC efficiency even more. COMMERCIALIZING THE PROCESS The promising process already has caught the eye of economic developers, who are helping scale up the effort. Through a Michigan Translational Research and Commercialization grant Reguera and her team are developing prototypes that can handle larger volumes of waste. Reguera also is in talks with MBI, the bio-based technology e-riskingenterprise operated by the MSU Foundation, to develop industrial-sized units that could handle the capacities of a full-scale biodiesel plant. The next step will be field tests with a Michigan-based biodiesel manufacturer i

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