More of the fuel, twice the food: Microbiogen’s yeast breakthrough

August 3, 2021 |

For years, it’s been ‘food vs fuel,” a claim that has plagued ethanol producers, that somehow producing fuel from crops would lead to less food production, and anti-ethanol forces painted pictures of mass starvation and land degradation. It was mostly a canard, but an effective one — generally, when fuel is introduced into the equation, farmers respond not by clearing land to make room for fuel crops, but by increasing the yield from the lands they already control. But, it’s been a nuanced argument.

No more, bioeconomy fans. Microbiogen and its global partner Novozymes have come up with a circular technology breakthrough that completely blows up, and blows away, the food vs fuel debate.

They now have a production yeast organism that produces lots of fuel, and now the yeast have been evolved to recapture their own glycerol waste stream and produce a single cell protein than can be used as animal feed.

Let’s put this in context. If you go to Brazil and utilize this process with the bagasse streams that are the waste product of sugarcane production, you get something special. With every acre you put into sugar production, you take away 2.4 hectares of land needed to grow food for cattle production. 

Less land for the cattle means less stress on land demand, and less pressure to clear Amazonian forest for cattle production. You solve the Amazonian problem not by avoiding ethanol production, but by embracing it.

It’s been a 15-year journey to commercialize technology ideas that MicroBiogen CEO Geoff Bell first developed with his year in the late 2000s. 

On the Balance Beam: managing heat and other problems

Yeast fermentation is exothermic, you produce heat when you do it, and the faster you run the fermentation, it’s like a car, it heats up, it can stress out and overheat. One of the things viewers learn about with elite swimmers during an Olympics is the need for athletes to cool off and recover between sessions, and keeping yeast cool enough to run fermentation is an art form where a balance is achieved between how much stress the yeast can tolerate and how fast the fermentation is run. 

So, that’s another aspect in making that ‘complete yeast package’ — it’s more than just producing strains, it’s making them all work in harness with each other. That’s one of the reasons that people might have this perception that new strains are being developed very quickly, because there are “model releases” that can come out each year, but actually these are often 10-year development efforts, it’s just that they are running in parallel.

Targeting the waste stream: the backstory

If yeast fermentation is the Indy 500 raceway of biomanufacturing, then glycerol is the pit stop. Glycerol is the dead end of the yeast fermentation process, it’s been biotechnology’s box canyon, no matter what you’re making via yeast, you’re making some glycerol because yeast do this to balance their internal health, just like Indy drivers pull off the track in the middle of the race to service the vehicle.

In some ways, glycerol is to yeast like sweat is to humans, something we produce to regulate our health, but we will not re-ingest later on for other purposes. You can read about most of the problems with this and the lack of solutions in this 2017 review, right here. 

“One of the ways you add value,” Bell told The Digest, “is how you think about the waste product. One way to think about it is simply to accept that after all the work you do in hydrolysis and fermentation and clean up, that you’ll have a lot of black stuff out the back which you’ll feed to the anaerobic digesters to make biopower. The other way is to attack that problem and develop the ability of yeast to grow on its own waste streams, so that you have more opportunity to recycle that wastewater. We have the yeast producing a single-cell protein, and it’s much more circular. We had that concept 15 years ago but it took 10 years to develop a yeast that grows efficiently on yeast, they can do it, but they aren’t good at it.”

ARENA steps in as a partner

After years of development in the lab, MicroBioGen’s $8 million project formally commenced in 2017 with the intention of optimizing yeast genetics to reduce the cost of 2G biofuel production and boost its performance on key sustainability metrics. The Australian Renewable Energy Agency (ARENA) stepped in with $4 million in support.

Bell told The Digest, “It’s the third grant we’ve received for the same target, because first you need the genetics, and then you need to get those genetics to work with everything else you want to happen with a production organism. You still need the tolerance for hydrolysis, the acid resistance, you want to leave less sugar behind, and have ethanol tolerance. It’s never one trait. Plus, we want high efficiency, less water use, more temperature resistance. We want all these things, and if you come up with a fantastic stain but it has one little flaw, that flaw will come back and haunt you at scale.”

It’s worked out well. MicroBioGen’s yeast achieved on average between 97% and 99% against each of the 13 success criteria established for the project.

Next Commercial Steps: Over to Novozymes

The global commercialization partner for Microbiogen is Novozymes, the Danish global enzyme giant which entered the Race for Elite Yeast a few years back. They are also a formidable technology partner, in their vast global lab system they also optimize the organisms that Microbiogen brings into the partnership, as well as taking the organisms into the market. So, it’s a true partnership.

How soon, in what form? For whom, and where and when? We’ll stand by to learn more as the commercialization process picks up steam.

The Sustainability Bottom Line

One thing we’re sure about, the organism enables some startling advances in sustainability.

A peer-reviewed analysis of the research findings found that 2G biofuel manufacture using MicroBioGen’s yeast strain and process, compared with benchmark commercial 2G yeast strains, reduced CO2 emissions by 29%, fossil energy use by 11% and water use by 75%.

All those are amazing. But there’s nothing more striking than that food production metric. Replacing 2.4 hectares of food crop need with every acre of sugarcane planted for ethanol. That’s on top of all those barrels of petroleum that remain in the ground.

That’s something that EVs can’t do — they solve a tailpipe emissions problem but do not address the food problem. Count on biology to take something that was considered ethanol’s weakness and turn it into a strength.

Not unlike the advice that basketball great Michael Jordan gave when he remarked, “My attitude is that if you push me towards something that you think is a weakness, then I will turn that perceived weakness into a strength.”

Geoff Bell puts it more directly. “For the first time ever, a single yeast strain – optimized using our proprietary technology – can produce both clean fuel and food from non-food biomass”.


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