Fatty acid methyl esters (FAMES), are produced through catalytic transesterification of soybean oil and other vegetable oils with methanol using KOH. The by-product glycerol is separated by settling, and the upper layer is decanted and dried by removing water through evaporation. The dried esters, mixed with urea, form urea inclusion compounds (UIC, photograph). The urea complexes with linear, fully saturated FAMES, leaving behind unsaturated esters suitable for processing into low carbon footprint fuels or biolubricants. Removal of the unsaturated FAMEs from linear, fully saturated molecules (responsible for forming crystals at low temperatures) decreases the cloud point and decreases temperatures at which these esters may be used.

Junli Liu, Bernard Y. Tao, Hao Feng, Nathan S. Mosier, Efficient rapid fractionation of fatty acid methyl esters (FAMEs) through evaporative urea inclusion, ChE Journal, 454 (2023) 140266.

https://www.sciencedirect.com/science/article/pii/S1385894722057461?via%3Dihub

An additional 100 million tons/year of lignin coproduct will result when lignocellulosic biomass is processed in biorefineries to fiber, sugars, biofuels, and bioproducts. This will double the amount of lignin already generated from pulping and paper production. Unlike pulping that results in lignosulphonate (88% of total) or Kraft lignin (9%), aqueous-based biorefining leaves behind non-sulfonated lignin and aromatic molecules. This new type of lignin provides opportunities for large volume uses as feedstocks for new chemistries that lead to molecular building blocks for the chemical industry and to precursors for sustainable aviation biofuels and s agricultural soil amendments (from TibTech 42(11) 2024.07.004. (2024): https://pubmed.ncbi.nlm.nih.gov/39127599/)

Xueli Chen, Nathan Moser, Michael Ladisch, Valorization of lignin from aqueous-based lignocellulosic biorefineries, Trends Biotechnol. 2024 Nov; 42(11):1348-1362. doi: 10.1016/j.tibtech.2024.07.004

The measurement of yield stress and shear thinning flow behavior of slurries formed from unpretreated corn stover at solids loadings of 100–300 g/L provides a key metric for the ability to move, pump, and mix this lignocellulosic slurry, particularly since corn stover slurries represent a major potential feedstock for biorefineries. This study compared static yield stress values and flow hysteresis of corn stover slurries of 100, 150, 200, 250, and 300 g/L, after these slurries were formed by adding pellets to a cellulase enzyme solution (Celluclast 1.5 L) in a fed-batch manner. A rotational rheometer was used to quantitate relative yield stress and its dependence on processing history at insoluble solids concentrations of 4%–21% (wt/vol). Key findings confirmed previous observations that yield stress increases with solids loadings and reaches 3000 Pa at 25% (wt/vol) solids concentration compared to 200 Pa after enzyme liquefaction. While optimization of slurry forming (i.e., liquefaction) conditions remains to be done, metrics for quantifying liquefaction extent are needed. The method for obtaining comparative metrics is demonstrated here and shows that the yield stress, shear thinning and shear thickening flow behaviors of enzyme liquefied corn stover slurries can be analyzed using a wide-gap rheometry setup with relative measuring geometries to mimic the conditions that may exist in a mixing vessel of a bioreactor while applying controlled and precise levels of strain (summary reproduced from abstract of Szeto et al, Biotechnol Progress, 2021;e3216 https://pubmed.ncbi.nlm.nih.gov/34590438/).

Ryan Szeto, Jonathan C. Overton, Antonio C. F. dos Santos, Clark Eby, Nathan S. Mosier, Eduardo Ximenes, Michael R. Ladisch, Kendra A. Erk, Rheology of enzyme liquefied corn stover slurries: The effect of solids concentration on yielding and flow behavior, Biotechnol Progress, 2021;e3216; https://doi.org/10.1002/btpr.3216