Characterization and Modeling of Bio-Oil and Protein Extraction From Biomass Using Ionic Liquid Based Co-Solvents

The use of ionic liquids to separate oils and proteins from biomass is a significant achievement in efficiently separating high quality jet and diesel fuels from abundant ocean algae and other agricultural feedstock.  Initial laboratory-based success has been demonstrated by researchers affiliated with the National Science Foundation Center for BioEnergy Research and Development, CBERD (Young et al., Separation & Purification Technology, vol. 72, 2010).  Micro-algae and oil-seed biomass were suspended in co-solvents mixtures comprised of ionic liquids of varying polarity and polar-covalent molecules and subjected to mild heating under reflux at atmospheric pressure. Yields of bio-oils extracted were calculated by gravimetric analysis, and the purity analyzed with NMR analysis.  In addition, light scattering and fluorescence techniques were utilized to investigate polarization/anisotropy in the co-solvent mixture, and their effects on lipid solubility and rates of diffusion.

In addition to experimental measurements, molecular dynamics simulations have been employed to probe the fundamental interactions between ionic liquid and polar covalent molecules in solution.  Radial distribution functions, along with simulation visualization, provide information on local fluid structure, and the molecular/structural basis for the experimentally observed auto-partitioning behavior.

Both experimental and simulation efforts provide an improved understanding of the relationship between molecular-level solvent structure and lipid solubility and diffusivity, which will help in the design of tailored ionic liquid/PCM solvent mixtures to optimize lipid extraction and separation, and ultimately biodiesel production.