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). In an ideal world striving for sustainability, we’d attempt to replace petroleum-derived products with lignocellulose-derived products because lignocellulose doesn’t compete with demand for food (i.e. we can eat starch, but we can’t eat lignocellulose). However, lignocellulose is difficult to valorize chemically: the Kraft pulping process uses caustic to separate cellulose from the lignin and hemicellulose, but the remaining lignin and hemicellulose mixture (which is called “black liquor”) has historically been too costly to separate. So, to solve that separation issue, Finland’s premier pulping company, UPM, is rethinking the entire process—instead of using caustic up front, they are doing a hydrothermal step that doesn’t modify the lignin and hemicellulose so much that the black liquor is rendered inseparable. The details aren’t clear to me, but after about a year of commissioning, that separation unit is officially up and running, and UPM is officially converting all of that cellulose and hemicellulose into sugars. This could be a big deal. UPM intends on converting those sugars into glycols (MEG and MPG), and they can still bring that lignin to market by selling it as a functional filler. [LINK]