University of Tübingen Researchers Develop Process to Convert Whey into Biofuel

Production of milk products produces a huge amount of wastewater in the factory. This wastewater, called "acid whey", cannot be fed to animals in large quantities due to its acidity. It is rich in organic material and must be treated or transported to farms for use as fertilizer.

University of Tübingen scientists have recently developed a process that converts acid whey, a dairy byproduct, into biofuels without the use of additional chemicals. Led by Professor Lars Angenent, the research team used microbiome cultures similar to those in the human gut. The new bio-oil can be used in animal feed or as a fuel for airplanes when refined.

The team used tanks with several types of bacteria, called a reactor microbiome. They kept two microbiomes with different temperatures. The first hot microbiome (50°C) converts all the sugars into an intermediate acid. The second warm microbiome (30°C) then performs chain elongation until a product is formed with six to nine carbons. The team also investigated which bacteria had grown in the two different microbiomes.

More work is now needed to study if other types of wastewater can also be converted into these valuable chemicals.