Refining of Ethanol Biorefinery Residues to Isolate Value Added Lignins

Abstract

The isolation of lignin coproducts from the residual solids of a hardwood based biocatalytic bioethanol process was examined, using extraction methods based on aqueous alkali or aqueous ethanol. This work focused on understanding how the structural features of raw lignin in the process residue influenced the refined lignin isolation yields, in addition to polymeric and structural characteristics. On the basis of this approach, the extraction based lignin refining could be optimized. Mild extraction conditions allowed for recovery of approximately 40 wt % of the lignin present in the starting material. This yield could be increased to about 76 wt %, by the application of base or acid catalyzed reactive extraction conditions liberating the bonded insoluble fractions of the residue. All isolated lignin products were characterized in terms of their functional groups, molecular weights and thermal properties. The lignins from mild alkali and ethanol extractions showed similarities in their chemical profiles. In contrast, the reactive extractions and degradative aqueous treatments produced structurally different lignins. As expected, the molecular weight and the thermal properties of the isolated lignins were affected by the isolation process and these differences are rationalized.

Biomass pretreatments capable of enabling lignin valorization in a biorefinery process

“…In the best case, marginal returns were predicted in addition to addressing the market risks. These findings support the actively occurring paradigm shift in lignocellulosic biorefinery research towards valorization of the lignin fraction from biomass [14][15][16][17][18][19][20][21][22][23][24][25][26].…”

Bio-based polyurethane foam preparation employing lignin from corn stalk enzymatic hydrolysis residues

“…Specially, lignin is an important and desirable candidate to replace petroleum-based polyols partially or totally for the production of bio-based PU foams due to its renewability, low cost, abundance and unique chemical structure. 7,8 As a promising source for sustainable and bio-base polymeric materials, lignin offers perspectives for higher-added-value applications such as exible, semi-rigid, rigid PU foams. 9,10 Lignin is arguably the second most abundant biopolymer on earth with cross-linked aromatic structure contained many phenolic and aliphatic hydroxyl groups.…”

Structural Analysis of Open-Column Fractionation of Peracetic Acid-Treated Kraft Lignin

“…In general, the method of isolating lignin from lignocellulosic biomass can be a acrucial factor in consideration of its end-uses (Ragauskas et al, 2014;Strassberger et al, -770 -2014). Most of lignin are produced in paper and pulp industries, and further processes for making the lignin as value-products have been attempted to improve economic value (Doherty et al, 2011;Lee et al, 2019;Leskinen et al, 2015).…”