Microbes help turn Greek yogurt waste into fuel

said braka 9:33 AM
"To be sustainable, you want to convert waste streams

where they are made, and upstate New York is where the cows are, where the dairy farmers are, and where the Greek yogurt craze began in the United States with Chobani and FAGE," says senior author Lars Angenent, an environmental engineer and microbiologist at Cornell University (United States) and the University of Tübingen (Germany). "That's a lot of  whey that right now has to be driven to faraway locations for land application, but we want to produce valuable chemicals from it instead."
Waste whey from Greek yogurt production is made up mostly of the familiar milk sugar lactose, the fruit sugar building block fructose, and the fermentation product lactic acid. The researchers use bacteria to turn this mixture into an extract containing two more useful compounds: caproic acid (n-hexanoic acid) and caprylic acid (n-octanoic acid). Both of these compounds are "green antimicrobials" that can be fed to livestock in lieu of antibiotics. Or, with energy needs in mind, further processing could stitch the six-, seven-, and eight-carbon backbones of the obtained molecules into the chains of up to 14 needed to qualify as "drop-in" biofuels for jet fuel.
Both options have economic and social allure. "The agricultural market might seem smaller, but it has a very large carbon footprint, and turning acid whey into a feedstock that animals can eat is an important example of the closed cycles that we need in a sustainable society," Angenent says. "The fuel market, of course, operates at a lower price, but its demand is virtually unlimited."


Read more at: https://phys.org/news/2017-12-microbes-greek-yogurt-fuel.html#jCp