Mississippi State University
Date of Degree
Dissertation - Open Access
Engineering, Chemical Engineering
Doctor of Philosophy (Ph.D)
James Worth Bagley College of Engineering
Dave C. Swalm School of Chemical Engineering
Lignocellulosic biomass represents the largest potential volume and lowest cost for biofuel and biochemical production. Harnessing the full potential of the lignocellulosic biomass for low-carbon energy requires the knowledge of efficient breakdown and fractionation of its carbohydrates and lignin. Organic solvent pretreatment is recognized as an emerging way ahead because of its inherent advantages, such as the ability to fractionate lignocellulosic biomass into cellulose, lignin, and hemicellulose components with high purity, as well as easy solvent recovery and solvent reuse. Through all-atom MD simulation, we analyze the conformational transition of diverse lignin molecules in varying concentration of Methanol/water , DMSO/water mixtures and neat DMSO , neat methanol and water. From our work, it appears that in 40 mol% DMSO and 40 mol% methanol mixture (’theta solvent’) hardwood lignin(G/S=1.35) conforms random coil like structure, while 60 mol% DMSO and 60 mol% methanol solution (at 300 K) appears to be ’good solvent’ for
hardwood lignin since it conforms extended chain like structure. While 80 mol% methanol is proven to be ’theta solvent’ and 80 mol% DMSO is proven to be ’good solvent’ for softwood lignin. We find that, major functional moieties of both lignin preferentially coordinated by methanol and DMSO molecules in increased organic solvents concentration which induces the conformational transition from crumbled globule to coil and prevent self-aggregation of lignin in binary mixtures. Chain dynamics of lignin explain the relaxation and subsequently elongated in addition of organic solvents into water.
Jahan, Nusrat, "Structure and dynamics of lignin in condensed phase for biomass conversion" (2022). Theses and Dissertations. 5654.
Available for download on Friday, December 15, 2023