MetGen, Sweetwater unlocking lignin – the roughest, toughest, ornieri’st material that ever bushwhack’d a pioneer in the Valley of Death

MetGen, Sweetwater Energy say “there’s gold in them thar side-streams”

By Jim Lane, Biofuels Digest
For all of your questions about the advanced bioeconomy there’s just the one answer and that is “lignin.”

Why don’t we see more biobased chemical plants built these days? Lignin. Why do people shy away from hardwoods as a raw material even though it’s sustainable, available, reliable and affordable? Lignin. What raw material have more people tried to make money out of and failed than anything else? Lignin. If the bioeconomy really catches fire, it’ll be because of a breakthrough in what? Lignin.

The Yosemite Sam of materials

It’s the meanest, toughest hombre of a material that ever came out of the ground, it’s the Yosemite Sam of the advanced bioeconomy — unreliable, inconsistent, grumpy, fiery, strident, incapable of improvement, impossible to do anything with, and impossible to ignore. So people just burn it. It smells faintly like vanilla and almonds, but it ought to smell like $20 bills going up in smoke.

“Ya no good, bush-whackin’ lignin, ya valueless varmint!

But trapped deep inside lignin are some aromatic molecules that are easily worth $1500-$2000 per tonne — more than fuels, more than most bulk chemicals. More than some people I know. And you can find them in wood, which sells for far less than $100 per ton as a raw material. Yet, if you walk around the biomass industry, you’ll find pellet plant after pellet plant — chopping up wood to sell to Scandinavia as a source of affordable, renewable heat and power. Worth perhaps $80 per ton in heat value.

What’s the problem? The answer to all your questions is lignin.

But there’s been more work on lignin of late than ever before. NREL has a lignin valorization project, focused on fractionating down into parts, and looking at multiple pathways to build those parts back up into molecules of value. The key? You have to get down to a small enough weight and size, and the more consistency the better. That’s where you unlock the true value

Good news, lignin fanbase. Sweetwater Energy has finalized a licensing and joint technology development agreement with the Finnish company MetGen Oy for MetGen’s LIGNO technology platform which facilitates the enzymatic break down of Sweetwater’s ultra-clean lignin into its fundamental component parts. This will allow the development of a full range of high value lignin-based products.

LIGNO’s secret? It’s MetGen’s enzyme set — in this case, bred for kraft pulp applications and thereby these alkaliphilic enzymes can effectively function at a pH up to 11, where lignin becomes fully soluble, with an added benefit of outstanding thermo-tolerance — think up to 80- degrees.

“Say yer prayers, lignin, ya long-chain’d galoot!”

Sweetwater and MetGen will carry out the commercialization of both technology platforms at Sweetwater’s small commercial facility in Rochester NY and will roll the technology out to facilities world-wide.

“I smells sugars a-cookin’ … and where there’s sugars, there’s value”: The Sweetwater backstory

From the outside, it might appear that Sweetwater has bounced around a bit, seeking the right technology fit. But the business vision has been consistent, precisely because it is a business vision and not a scientific odyssey to develop a solution and then find a problem to fix.

The goal has been realizing value out of, initially, hardwoods. For cellulosic anything, the main cost is in the feedstock, and if you don’t extract the full value, you’ll find it impossible to compete with corn — much less petroleum. Corn doesn’t leave anything on the table.

So it comes down to lignin. Because if you are getting 60% yield on the sugars and getting $80/ton of value on the lignin, you can’t make a viable business. In hardwoods or anything else.

Pretreatment has been the bear for Sweetwater — they’ve worked with four different technologies, painfully and slowly, and finally they came across Sunburst, which they developed as a patented process that converts over 94% of total sugars to monomeric sugars, while producing few downstream inhibitors. Most recently, Sweetwater Energy achieved what it described as “world-record results”, more than 91 gallons of industrial ethanol per dry metric tonne of biomass.

As Sweetwater’s Scott Tudman explained to The Digest, “pretreatment for us is the critical step, we were searching, we wanted to get 90% of the sugar or more, and then a clean lignin residual you could monetize. Sunburst gets us there, and in our model the lignin now yields more than what we get from the sugar. We’re almost on the verge of being a lignin company, because this collaboration with MetGen allows us to fully unlock that lignin value, and with that high value we can bring down the cost of cellulosic sugars, and compete with cane and corn.”

Sweetwater recently upgraded its demo facility to process biomass at a small commercial level– up to three tons of biomass per day, using a state-of-the art extrusion technology at its core. Sweetwater is achieving over 97% hemicellulose conversion to monomeric sugars in less than 10 seconds, and over 93% conversion of cellulose to monomeric glucose through enzymatic hydrolysis, fully converting 94% of total theoretical sugars in the original biomass to monomers.

“Solubilize faster, you lily-livered lignin … Solubilize faster or I’ll blast your head off!”: The MetGen gambit

“Enzymes have to be about more than hydrolysis,” MetGen CTO Matti Heikkilä told The Digest. “Given the price of wood raw materials, you cannot afford to not use the 30% lignin content,. You have to valorize. But it’s a very complex molecule set, with lot of rings attached and no particular form, and burning is an easy way out.”


The problem, as MetGen and Sweetwater explain, is in the solubility. If you can solubilize lignin, you can get it down to to well below 50 kilodeltons, and then you can start to put it in adhesives and could replace formaldehyde.


“Down in that .3, .5 , 7 kilodeltons range,’ said Heikkilä, “you are almost at the primary precursors, down to 2-4 ring complexes and now you can do quite specific applications — foams, composite PVA packaging.” Caution here. MetGen isn’t developing a drop-in form of biobased PVA. Rather, this is about making materials that do the same job — that command values in the range of $1500-$2000 per tonne.


“I paid my four bits to see the high divin’ act … and I’m-a gonna see the high diving act!: MetGen and Sweetwater, together

So, this partnership is about matching Sweetwater’s UltraClean lignin to MetGen’s LIGNO technology — but is this a tactical partnership of two companies that think alike about capturing value and like to collaborate — or are there technical and value reasons that these two techs go together well?

Think, “a bit of both.”

Yes, it’s a long-standing relationship and they share a vision on the importance of lignin valorization. And yes, MetGen’s enzymes are robust and will work with multiple raw materials and processes. So, why Sweetwater?

For MetGen, it comes down to yield. You see, lignin’s always been the stepchild in the value chain and everyone has chased and teased out all the sugars they can find, and then all that residue from sugar extraction gets thrown out with the lignin. So, the lignin side-stream is filled with things that aren’t lignin, including residual carbohydrates. It doesn’t kill the MetGen enzyme, but you impact yield. The cleaner and purer the lignin, the more value you get. More sugar in the first pass, purer lignin in the side-stream. Whether this is about plastic foams or adhesives and resins.

For Sweetwater, it’s about that valorization drive. Their UltraClean lignin is good as filler, but not yet consistent enough and at too wide a particle size to be exciting to the likes of Dow DuPont as a pathway to new chemistries — where the value is. So, perfect together in many ways.

Blast my scuppers, why isn’t anyone else doing this?

It’s as if everyone gave up.

“There’s been surprisingly little of high quality material in relevant quantities available for application work. =” said Heikkilä. “We’re pioneering and have a good head start.”

So, ya lignin-lovin’ buck-toothed barnacle, what’s next?

Look for Sweetwater to wrap up a Series B funding for the company and the financing for it’s first commercial plant in Minnesota as soon as this fall.

Sweetwater CEO Arunas Chesonis told The Digest, “Plant 1 is for industrial alcohol that’s GMO free — we get over a half dollar premium for that, it’s a simple product to make, and it’s a small market well suited to a small commercial plant where we can produce 4 million gallons and prove our pretreatment process works. For now we’ll sell the lignin into the activated carbon market, and 6000 tons per year with that, and we have two sets of offtakes for the plant’s production.

How is the company getting through the problem of technology risk? They’re taking the insurance route on that and expect to have that wrapped up in the next 90 days, also.

Feedstock, not yet signed, but the company said that the Minnesota needs a relatively nominal 50,000 tonnes for the small commercial plant — easy for the market to handle. It’s a $100 million project and will require half equity, half debt.

But then, there’s Europe, too. The Horizon 2020 program has big budgets snd big ambitions and for a big flagship EU project, those clean Sweetwater sugars and their high yields will come in handy to make the numbers work, so we wouldn’t drop dead of surprise if the two partners become part of a big Horizons 2020 application.

The Bottom Line, ya’ muley-headed maverick

As we said, no matter your question, lignin is the answer. Including to a question like “a breakthrough in what area will transform cellulosics from a sideshow to the main show?” So, it’s the right time and the right focus — the partners believe they have it nailed, and we won’t have long to wait to see whether and to what extent this will transform markets.

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