Codesign of Combinatorial Organosolv Pretreatment (COP) and Lignin Nanoparticles (LNPs) in Biorefineries
journal contributionposted on 28.12.2018, 00:00 by Zhi-Hua Liu, Naijia Hao, Somnath Shinde, Michelle L. Olson, Samarthya Bhagia, John R. Dunlap, Katy C. Kao, Xiaofeng Kang, Arthur J. Ragauskas, Joshua S. Yuan
To make biorefineries sustainable, codesign of fractionation technologies and lignin valorization has been found to be essential. Combinatorial organosolv pretreatment (COP) was thus developed in an effort to efficiently produce sugars and improve lignin processability for the fabrication of lignin nanoparticles (LNPs). COP produced greater than a 90% glucose yield and 73% xylose yield, suggesting the improved sugar release from biomass. LNPs were fabricated from the lignin fractionated by COP via antisolvent precipitation. The smallest effective diameter (142 nm) of LNPs was obtained from COP using EtOH plus sulfuric acid. These LNPs possessed a lower polydispersity index and higher zeta potential, suggesting superior uniformity and greater stability. The lignin characterization results indicated that COP using EtOH plus sulfuric acid cleaved more β-O-4 and β–β linkages and produced lignin with a higher molecular weight and increased G-lignin and C5-substituted OH contents, suggesting the generation of condensed lignin. These modifications enhanced the hydrophobic interactions between lignins and thus enabled the fabrication of LNPs with a small particle size. COP using EtOH plus sulfuric acid also enriched total phenolic OH content and could promote the formation of a hydrogen-bonding network within LNPs. Together with a high zeta potential due to the increased phenolic OH and COOH groups, the stability of LNPs was thus enhanced. Overall, COP increased the sugar release from biomass and improved the lignin processability to facilitate the design of LNPs with satisfactory properties, which showed the potential to improve the lignin valorization and the sustainability of biorefineries.