Institut Carnot 3BCAR is the French Public R&D Institute dedicated to Bio-energy, bio-molecules and bio-materials having in common renewable carbon from agriculture and forestry as raw material source. 3BCAR is a network of research laboratories coordinated by INRA (Institut National de Recherche Agronomique) installed on three main sites: Toulouse for White biotechnologies, Montpellier for systemic analysis and eco-conception, Versailles for green biotechnology and biomass treatment. During the annual scientific Forum organized by 3BCAR, Stéphanie Baumberger, an Agro ParisTech professor and head of APSYNTA research team of Inra Versailles presented a paper on lignin as key source of bio-molecule, summarized below.
Second generation bio-refineries are delivering sample quantities of workable lignin, a natural oligomer that remains after extraction of cellulosic sugars (cellulose and hemicelluloses) from the in-feed biomass. Unlike the historical so-called Kraft or sulfate process historically used by the pulp and paper industry to extract pure cellulose from forestry biomass, new gentle extraction processes are able to keep the lignin oligomer’s endings active for further chemical combinations.
Three thermo-chemical processes currently co-exist for biomass pre-treatment and fractionation: alkaline, using NaOH, Organosolv, using organic acids, and steam-cracking. Of the three, only the alkaline pre-treatment has been demonstrated at commercial scale. The two others have only been tested at demo-plant or pilot plant scale.
Another cellulosic sugars extraction path is being explored and has been developed at pre-commercial scale: the enzymatic fermentation technology. Beta Renewables, a JV between M&G CHEMTEX (Italy) and NOVOZYMES (Denmark) as well as the alliance between DSM (Holland) and DONG (Denmark) are producing bio-ethanol using their respective patented enzymatic fermentation technology. But the lignin remaining form this process is reportedly too polluted with sugars to be workable in downstream chemical processes and is therefore used an on-site combustible.
Workable lignin form soft processes can be further valorized into phenolic compounds, carbon fibers or thermo polymers.
Along with the discovery of pure lignin characteristics and functionalities, namely hydrophobia, reticulation, entrapping or free radicals, antioxydation, further added value applications can be envisaged. These range from the replacement of petrochemicals phenol in phenol formaldehyde glues for wood panels to the production of bio-based polyester, polyurethane and epoxy. (Please refer to the specific article in this blog under “the future of epoxy resin “)
A data base of global lignin production is regularly updated by the International Lignin Institute (ILI). At this stage, workable lignin from soft processes are available in sample quantities for R&D programs and commercial quantities should not be available before 2015 or beyond, with the notable exception of alkali lignin already available from India. It is more than likely that China, India and Brazil where available agricultural biomass is abundant and cheap will be important producers of pure lignin in the future.