Deriving high value products from depolymerized lignin oil, aided by (bio)catalytic funneling strategies

Abstract

Lignin holds tremendous and versatile possibilities to produce value-added chemicals and performing polymeric materials. Over the years, different cutting-edge lignin depolymerization methodologies have been developed, mainly focusing on achieving excellent...

Economic and Environmental Trade-Offs of Simultaneous Sugar and Lignin Utilization for Biobased Fuels and Chemicals

“…Medium and high lignin biomass feedstocks, such as switchgrass and clean pine, require a lignin-to-bioavailable intermediates conversion of at least 41 and 33 wt %, respectively, to make the lignin utilization strategy economically viable over lignin combustion. These yields can be achieved, particularly with reductive or oxidative catalytic depolymerization methods. ,− The average monomer yield is approximately 30 wt % for hardwood and herbaceous crops, ,,,, and yields exceeding 50 wt % are regularly reported for hardwood , with the reductive catalytic depolymerization method. Monomer yields from oxidative depolymerization methods are mostly reported in the range of 20–40 wt %, ,− while the lowest average monomer yield mostly in the range of 10–20 wt % is reported for the acid- or base-catalyzed depolymerization process.…”

“…Host microbe optimization is one of the key areas that needs improvement. Although lignin-to-monomers conversion yields mostly in the range of 20–50 wt % have been demonstrated, ,− the development of high-performance microbes that can simultaneously catabolize sugars and lignin-derived intermediates is still in its very early stages. Most prior biological lignin upgrading work has focused on converting lignin monomers into commodity chemicals and high-value products, including indigoidine, vanillin, muconic acid, polyhydroxyalkanoates, methane, and lipids, using different host organisms such as Pseudomonas putida and Rhodococcus opacus.…”

“…These yields can be achieved, particularly with reductive or oxidative catalytic depolymerization methods. 42,57−62 The average monomer yield is approximately 30 wt % for hardwood and herbaceous crops, 42,58,59,61,62 and yields exceeding 50 wt % are regularly reported for hardwood 61,62 with the reductive catalytic depolymerization method. Monomer yields from oxidative depolymerization methods are mostly reported in the range of 20−40 wt %, 57,60−62 while the lowest average monomer yield mostly in the range of 10−20 wt % 61 is reported for the acidor base-catalyzed depolymerization process.…”

“…Similar results for GHG emissions are documented in Supporting Information Figures S9–S11. Recent studies ,− have shown that the lignin-to-monomers conversion typically ranges from 20 to 50 wt %. Assuming that all lignin monomers are efficiently consumed by microbes along with sugars, the yield of these monomers falls at least 1.7 times short of reaching cost-parity with lignin combustion for biomass sorghum.…”

Aniline Derivatives from Lignin under Mild Conditions Enabled by Electrochemistry

“…[26] More specifically for the electrochemical oxidation of lignin-derived phenols, we envisage that the inherent functionalities might play an active role in the formation of more reactive cyclohexadienone intermediates. For instance, lignin-derived 4propanolguaiacol (1G) and 4-propanolsyringol (1S), recurrent platform chemicals obtained by reductive catalytic fractionation (RCF), [27] undergo spiroannulation reactions towards the formation of spirodienones, [28,29] previously demonstrated by chemical oxidation. Additionally, the anodic oxidation of 2-alkoxyphenols such as 4-propylguaiacol (2G), [30,31] 4-ethylguaiacol (3G) and respective syringol units (2-3S), might also lead to the generation of ortho/para quinone monoketals [32] in the presence of MeOH as both solvent and nucleophile (See Figure 1B).…”