Washington State University researcher's new and novel method to
extract lignin could help spin wheat straw into cash.
Lignin, a
super tough biomaterial has been a problem in biofuel
production.
Lignin produced using the new method was
color-neutral, odorless and homogenous, an advance that could make
this carbon-neutral material a more viable candidate for development
of high-value products.
The researchers
reporting in the Proceedings of the National Academy of Sciences they
extracted up to 93% lignin with up to 98% purity from wheat
straw, producing a significant amount of
material in a uniform way that could make it more attractive
for industry use.
Xiao Zhang, professor in WSU's Gene and Linda
Voiland School of Chemical Engineering and Bioengineering, who led the
work said, "This method allows us to extract lignin from plant
material in its native form and at a high yield. We were able to
demonstrate to industry that it is possible to make color-neutral and
odorless lignin, and we can make quite a bit of the material to begin
evaluating its applications."
Lignin is the second most abundant renewable
carbon source, making up about 30% of the non-fossil fuel-based carbon
on Earth. It is in all vascular plants, where it forms cell walls and
provides plants with rigidity. Lignin allows trees to stand, gives
vegetables their firmness and makes up about 20%-35% of the weight of
wood. The material holds great promise as a precursor for biobased
materials and fuels, but it is also notoriously difficult to extract
from plants.
The material is usually separated during
papermaking and biorefining, but these processes often contaminate and
significantly alter lignin's chemical and physical properties,
decreasing its value. So most lignin is either burned to produce fuel
and electricity or used in low-value products, such as for cement
additives or as a binder in animal feed. Producing a more homogenous
lignin provides the opportunity to pursue high-value material
development to replace petroleum-derived plastics and polymers.
"Because of its heterogeneity, lignin can't be
used as a valuable material despite centuries of effort," said Zhang,
who holds a joint appointment with Pacific Northwest National
Laboratory. "The saying has been that 'you can make anything out of
lignin, except money.' There's so much heterogeneity in the molecules
that nobody can reliably make things out of it."
In their work, the researchers used a solvent
to separate the lignin from wheat straw and were able to preserve and
control its key properties, producing a more uniform molecule with a
consistent molecular weight that makes it more useful for industry.
The lignin extracted was light-colored, which is more like the lignin
that exists in nature.
Because it is an electron-rich compound, the
lignin had a strong affinity for the solvent, and the electron
interactions allowed the researchers to extract it with minimal
chemical reactions, which protected its natural molecular structure
that is so often easily damaged in chemical separations.
WSU's Office of Commercialization has filed a
provisional patent and will assist the researchers for the scale-up
and eventual commercialization of this technology. To make it more
viable for industry applications, the research team is working to
decrease the lengthy processing time and the amount of purification
chemicals needed.
The work was done in collaboration with
Edoardo Apra, a computational scientist from PNNL, and Professor Art
Ragauskas from University of Tennessee, Knoxville. It was supported by
the National Science Foundation and the U.S. Department of Agriculture
National Institute of Food and Agriculture as well as WSU's
Commercialization Gap fund.
The news is sure to excite some folks as
lignin has been a barrier to some ideas for biofuels and other energy
related efforts. The problem is often that lignin is built with
molecules that are useful yet so bound us as to be useless or worse.
That bound up matter tends to lock up the sugars and starches most
useful and desired.
The press release is forthright enough that
some of the early matters are mentioned such as processing time and
purification. Of note, one wonders about the safety and recyclability
of the solvent and the other chemicals.
Ultimately the market will look at the end
lignin product and what opportunities it may present. Will there be
more than one form such as a fine dust or a matt? Time will tell. But
lignin is very tough stuff and getting it into the materials market
instead of trying to extract the components for biofuels sound like a
very very good idea indeed.
By Brian Westenhaus via
New Energy and Fuel
More Top Reads From Oilprice.com:
Green Play Ammonia™, Yielder® NFuel Energy.
Spokane, Washington. 99212
509 995 1879
Cell, Pacific Time Zone.
General office:
509-254
6854
4501 East Trent
Ave.
Spokane, WA 99212
