Across the Board: Mark Mascal on the Challenges of Lignin Biorefining

Abstract

In this series of articles, the board members of ChemSusChem discuss recent research articles that they consider of exceptional quality and importance for sustainability. This entry features Prof. M. Mascal, who describes some creative solutions to the challenge of lignin biorefining and shares thoughts about how the purposes of sustainability are best served. Topics discussed include lignin saturation and hydrodeoxygenation, lignin isolation, a lignin to muconic acid pathway, and the production of 2,4‐ and 2,5‐pyrinedicarboxylic acids from lignin.

Lignin Depolymerization under Continuous‐Flow Conditions: Highlights of Recent Developments

“…Another promising approach is biological lignin valorization, [19, 20] which aims at exploiting the multitude of aromatics resulting from chemical depolymerization through funneling to one or two intermediates. The strategy relies on engineered microbial platforms that can uptake and metabolize such lignin‐derived intermediates for further conversion into value‐added compounds, such as cis , cis ‐muconic acid and 2,4‐ or 2,5‐pyridinedicarboxylic acid [21] …”

“…The strategy relies on engineered microbial platforms that can uptake and metabolize such lignin-derived intermediates for further conversion into value-added compounds, such as cis,cis-muconic acid and 2,4-or 2,5-pyridinedicarboxylic acid. [21] Understanding and improving technical lignin transformations under continuous-flow conditions could facilitate the transition towards industrial application. The continuous depolymerization of lignin has a number of advantages compared to batch-mode processing (Figure 2).…”

Mechanism of Ligand‐Controlled Chemoselectivity‐Switchable Ni‐Catalyzed C−N Cross‐Coupling of Amine

“…With Ni as the catalyst, Buchwald's group reported the Ni‐catalyzed amination of aryl chlorides with 1‐substituted piperazines, [41] Hartwing's group reported Ni‐catalyzed monoarylation of amine or ammonium salt, [42] MacMillan's group reported ligand‐free Ni(II) and photoredox catalysis aryl amination [43] . During the last decade, numerous reactions have been developed for the functionalization of aryl halides via the Ni‐catalyzed [44–56] . In this context, Stradiotto et al.…”

Response of Pseudomonas putida to Complex, Aromatic‐Rich Fractions from Biomass

“…upgrade the aromaticsd erivedf rom this depolymerization. [7][8][9][10] This strategy relies on the ability of these hosts to assimilate these low-molecular-weight (LMW) products as carbon sources. [9,[11][12][13] To achieve this objective, chemical lignin depolymerization methods have been developed to maximize the generation of these aromatic monomers.…”

“…A promising lignin valorization strategy for grasses couples chemical lignin depolymerization with the microbial catabolism of aromatic monomers by hosts that have been engineered to upgrade the aromatics derived from this depolymerization . This strategy relies on the ability of these hosts to assimilate these low‐molecular‐weight (LMW) products as carbon sources .…”