Improving lignocellulosic biofuel biorefining

May 20, 2014, Atlanta, GA – A new review article in the
journal Science points the way toward a future where lignin is transformed from
a waste product into valuable materials such as low-cost carbon fiber for cars
or bio-based plastics. Using lignin in this way would create new markets for
the forest products industry and make ethanol-to-fuel conversion more
cost-effective.

“We’ve developed a roadmap for integrating genetic
engineering with analytical chemistry tools to tailor the structure of lignin
and its isolation so it can be used for materials, chemicals and fuels,” said
Arthur Ragauskas, a professor in the School of Chemistry and Biochemistry at
the Georgia Institute of Technology. Ragauskas is also part of the Institute
for Paper Science and Technology at Georgia Tech.

The roadmap was published May 15 in the journal Science.
Co-authors of the review included scientists from the National Renewable Energy
Laboratory and Oak Ridge National Laboratory.

The growth of the cellulosic fuel industry has created a
stream of lignin that the industry needs to find valuable ways to use. At the
same time, federal agencies and industry are funding research to simplify the
process of taking biomass to fuels.

“One of the very promising approaches to doing that is to
genetically engineer plants so they have more reactive polysaccharides suitable
for commercial applications, but also to change lignin’s structural features so
that it’ll become more attractive for materials applications, chemicals and
fuels.” Ragauskas said.

Research highlighted in the review has shown it’s
theoretically possible to genetically alter lignin pathways to reduce
undesirable byproducts and more efficiently capture the desired polysaccharides
– which are sugars that can be converted to other products – and enhance
lignin’s commercial value.

“There are sufficient publications and data points out there
to say that say, ‘Yes, we can do this,’” Ragauskas said.

Through work on transgenic plants and wild plants that
naturally have fewer undesirable constituents, biologists, engineers and
chemists have recently improved the biorefinery field’s understanding of the
chemistry and structure of lignin, which provides a better idea of the theoretical
chemistry that lignin can do, Ragauskas said.

“We should be able to alter the structure of lignin and
isolate it in such a manner that we can use it for green-based materials or use
it in a blend for a variety of synthetic polymers,” Ragauskas said.

Doing so would create a stream of polysaccharides for use as
ethanol fuels, with lignin waste that has structural features that would make
it attractive for commercial applications such as polymers or carbon fibers.

The science could be applied to a variety of plants
currently used for cellulosic biofuel production, such as switchgrass and
poplar.

Today, lignin is mostly burned for energy to fulfill a small
amount of the power requirements of the ethanol biorefineries. But the new
roadmap emphasizes how, through genetic engineering tools that currently exist,
lignin could become much more valuable to industry.

“Our primary mission is to reduce the cost of taking biomass
to biofuels,” Ragauskas said, “But in the process we’ve learned a lot about
lignin, and we might be able to do more than just reduce cost. We might be able
to tailor lignin’s structure for commercial applications.”

Co-authors on the review article included scientists from
the National Renewable Energy, the University of British Columbia, the
University of North Texas, Oak Ridge National Laboratory, and the University of
California, Riverside.