Turning Greek Yogurt Waste Into Bio-Jet Fuel

Turning Greek Yogurt Waste Into Bio-Jet fuel
Turning Greek Yogurt Waste Into Bio-Jet fuel

A Source For Bio-Jet Fuel and Other Fossil Fuels.

Airline travel is on the rise and as prices fall for international travel, aerospace companies are taking orders for new airplanes at almost an alarming rate. Alarming that is if you care about atmospheric and ocean born CO2 levels and the impact on global climate.

Today’s airplanes use Jet fuel which is also known as kerosene but no mater what you call the fuel , it is made from fossils and combustion of it releases CO2. Is there not a replacement fuel that we can use until we perfect the electric airplane? ( Yes Boeing and Airbus are developing this).

HY4 electric flight powered by a fuel cell

HY4: Electric flight powered by a fuel cell. Image courtesy of DLR. Electric would be better than even using bio-jet fuel.

Right after jet-fuel as far as consumption is diesel fuel, used for everything from large trucks to electric generators and trains this fossil. Diesel fuel also needs a replacement. Trains and buses really do not need to be diesel as even today there are all electric options and some of the trains are unbelievably fast!

Electric highspeed trains give us insight into tomorrows electric vehicles

I was recently on a train from Switzerland to Germany that was completely powered in this way. The grid of the future may also provide electricity ( clean I hope ) to the roadways for wireless vehicles.

What to do right? How about Yogurt as a feed-stock for bio-jet fuel, diesel and gasoline?

Consumers across the world enjoy Greek yogurt for its taste, texture, and protein-packed punch. Reaching that perfect formula, however, generates large volumes of food waste in the form of liquid whey. Now researchers in the United States and Germany have found a way to use bacteria to turn the leftover sugars and acids from Greek yogurt into molecules that could be used in biofuels or safe feedstock additives. Their work appears December 13 in the journal Joule.

bio-oil greek yogurt

This is a photograph of bio-oil, made of caproic acid and caprylic acid, phase separates out at mildly acidic conditions. A way to make Bio-Jet Fuel.
Lars Angenent, University of Tübingen

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 acid 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” bio-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.

Traditionally, suppressing oxygen while feeding biodegradable waste to microbes results in the production of methane-rich gas through anaerobic digestion. Instead, the researchers strung together two “open-culture” reactors–the first tuned for heat-loving microbes fond of temperatures of 50°C, the second set at a more welcoming 30°C mark. After seeding each reactor with a previously studied microbiome, and opening the setup to the acid whey and its own rich assortment of bacteria (such as common gut microbiota from the Lactobacillus family), caproic acid, caprylic acid, and other minor products could be continually extracted over a period of several months.

The next challenge will be to see what happens when the twin bioreactor system is boosted to pilot plant capacity.

There is much more that can be done to optimize the extraction process and to scale up in an economical way. We can also learn more about the nature of the microbiomes and the biology involved and start investigating whether this technology can be translated to other waste streams.

About the Research

This work was supported by the Alexander von Humboldt Foundation, the New York State Department of Environmental Conservation, the USDA National Institute of Food and Agriculture, and the Cornell University Agricultural Experiment Station.

After thoughts. I read recently that at least in the US and Canada, that dairy farmers are awash in milk as consumers switch to almond, soy, coconut and other types of non-dairy milk replacements. This seems like a real opportunity to make use of this excess milk production to make bio-jet fuel and other fuel replacements. Just a thought

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