Lignocellulosic biomass converter, New Energy Blue, announced that Dow Chemical has signed an offtake agreement from its upcoming corn stover processing plant in Mason City, Iowa, which is expected to produce ethylene.

A little background:

At a high level, you can think of biomass (plants, trees, etc.) as being composed of two types of polymers: polymers for energy storage, and polymers for structure. Your energy storage polymers are amylose and amylopectin (jointly referred to as starch) and your structural polymers are cellulose, hemicellulose, and lignin (jointly referred to as lignocellulose). Historically, with the exception of making paper, we’ve utilized the starch fraction and wasted the lignocellulosic fraction.

Okay, so what’s the deal here?

Converting either of those polymeric fractions into smaller building block chemicals requires some depolymerization—that starts with making the individual atoms and bonds more accessible (pre-treatment), depolymerization with an enzyme, followed by conversion of that product (sugars) into chemicals like ethanol via fermentation. Generally speaking, the costs here are proportional to how complex the initial polymer is, and lignocellulose is a far more complex jumbled mess than starch. But Inbicon’s lignocellulosic conversion process saw some success in Europe, so New Energy Blue bought exclusive rights to use it, and plans to do so by 2025.

Connecting the dots:

Dow produces ethylene by steam cracking ethane or naphtha, and they use that ethylene to a whole slew of different chemicals and materials. If New Energy Blue is able to successfully produce lignocellulose-based ethanol, and can facilitate the dehydration of that ethanol into ethylene, then Dow will just feed that ethylene directly into its existing units. The questions we should be asking are a) “will New Energy Blue’s plant actually be built?”, and b) “will ethanol ever be able to replace ethane or naphtha at scale?”

Netherlands-based sustainable chemicals company, Avantium, was granted $1.6 million from the EU Horizon Europe Research and Innovation program to demonstrate a process for converting CO2 into polylactic-co-glycolic acid (PLGA).

Getting you up to speed:

Avantium was spun-off from Shell in the early 2000s, and has since been working to commercialize the production of a polymer called polyethylene furanoate (PEF) via the polycondensation of FDCA and ethylene glycol (MEG). But that’s not the only thing they’ve been working on—they’re also developing a process for processing lignocellulose, producing sugar-based ethylene glycol, and valorizing CO2.

Okay, so CO2 and PLGA?

Back in 2017, Avantium acquired Liquid Light, who had developed an electrochemical process that reduces CO2 to formate, couples the formate to make oxalate, and then acidifies that oxalate to make oxalic acid. That oxalic acid could then be reduced with hydrogen all the way to ethylene glycol, or it could be reduced partially to glycolic acid. That glycolic acid could then be co-polymerized with lactic acid to make PLGA.

Zooming out:

Our options for more sustainable feedstocks are fairly limited: we’ve got biomass, waste, and CO2. Each faces its own set of issues, but the ones CO2 faces are less about an ability to scale from a systems perspective, and more about an inability to a) overcome unfavorable thermodynamics in a cost-effective manner, and b) be converted into a product with a large end market. But since utilizing CO2 is a far more compelling business proposition than government-subsidized sequestration, it’s probably worth researching.