2 research outputs found
Molecular Dynamics Studies on the Adaptability of an Ionic Liquid in the Extraction of Solid Nanoparticles
Recently, a number of publications have suggested that
ionic liquids
(ILs) can absorb solid particles. This development may have implications
in fields like
oil sand processing, oil spill beach cleanup, and water treatment.
In this Article, we provide a computational investigation of this
phenomenon via molecular dynamics simulations. Two particle surface
chemistries were investigated: (1) hydrocarbon-saturated and (2) silanol-saturated,
representing hydrophobic and hydrophilic particles, respectively.
Employing 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]Â[PF<sub>6</sub>]) as a model IL, these nanoparticles were allowed to equilibrate
at the IL/water and IL/hexane interfaces to observe the interfacial
self-assembled structures. At the IL/water interface, the hydrocarbon-based
nanoparticles were nearly completely absorbed by the IL, while the
silica nanoparticles maintained equal volume in both phases. At the
IL/hexane interface, the hydrocarbon nanoparticles maintained minimal
interactions with the IL, whereas the silica nanoparticles were nearly
completely absorbed by it. Studies of these two types of nanoparticles
immersed in the bulk IL indicate that the surface chemistry has a
great effect on the corresponding IL liquid structure. These effects
include layering of the ions, hydrogen bonding, and irreversible absorption
of some ions to the silica nanoparticle surface. We quantify these
effects with respect to each nanoparticle. The results suggest that
ILs likely exhibit this absorption capability because they can form
solvation layers with reduced dynamics around the nanoparticles
Muconic Acid Production <i>via</i> Alternative Pathways and a Synthetic “Metabolic Funnel”
Muconic
acid is a promising platform biochemical and precursor
to adipic acid, which can be used to synthesize various plastics and
polymers. In this study, the systematic construction and comparative
evaluation of a modular network of non-natural pathways for muconic
acid biosynthesis was investigated in <i>Escherichia coli</i>, including <i>via</i> three distinct and novel pathways
proceeding <i>via</i> phenol as a common intermediate. However,
poor recombinant activity and high promiscuity of phenol hydroxylase
ultimately limited “phenol-dependent” muconic acid production.
A fourth pathway proceeding <i>via</i> <i>p</i>-hydroxybenzoate, protocatechuate, and catechol was accordingly developed,
though with muconic acid titers by this route reaching just 819 mg/L,
its performance lagged behind that of the established, “3-dehydroshikimiate-derived”
route. Finally, these two most promising pathways were coexpressed
in parallel to create a synthetic “metabolic funnel”
that, by enabling maximal net precursor assimilation and flux while
preserving native chorismate biosynthesis, nearly doubled muconic
acid production to up to >3.1 g/L at a glucose yield of 158 mg/g
while
introducing only a single auxotrophy. This generalizable, “funneling”
strategy is expected to have broad applications in metabolic engineering
for further enhancing production of muconic acid, as well as other
important bioproducts of interest