Sandia researcher Eizadora Yu prepares biomass harvested from liquid fungal cultures for nucleic acid analysis. The cultures come from the endophytic fungus Hypoxylon sp, which produces compounds potentially used for fuel. (Image by Dino Vournas) |
Engine experts and
biofuels researchers at Sandia National Laboratories are working on a project
that aims to modify an endophytic fungus so that it will produce fuel-type
hydrocarbons for transportation purposes.
The biofuels being
investigated for the project are produced by a class of fungi—endophytes—that
live between plant cell walls. The cellular material in plant walls can be
converted into hydrocarbon compounds that work well as fuels for internal
combustion engines. Sandia is collaborating with Professor Gary Strobel from
Montana State Univ., a known expert in Ascocoryne
sarcoides and other similar fungi.
The beauty of the
endophytic fungi, Sandia biochemist Masood Hadi said, is that there is no need
for the cost-intensive industrial processes that are typically required to
break down biomass. “These things can turn crystalline cellulosic material
directly into fuel-type hydrocarbons without any mechanical breakdown,” he
said.
These fungi, in other
words, are designed by nature to grow on cellulose and to digest it, forming
fuel-type hydrocarbons as a by-product of their metabolic processes. Through
genetic manipulation, the Sandia team hopes first to identify these pathways,
and then to improve the yield and tailor the molecular structure of the
hydrocarbons it produces
Finding a
fuel-friendly mix of molecules
Sandia’s
bioscience team is using genetic sequencing to catalog the pathways and other
molecular biology techniques to understand how changes in feedstock determine
the type and amount of hydrocarbons the fungi make, with a long-term goal of
engineering greater quantities of the desirable fuel species. Meanwhile, Craig
Taatjes and John Dec, both engine combustion researchers at Sandia, are
experimenting with the main compounds produced in the molecular “soup” and give
feedback to their bioresearch counterparts on their ignition chemistry and
engine performance. The ideal outcome, Dec said, is to “dial in” the right
feedstocks combined with the right set of genes to produce the preferred blend
of compounds to go into an engine.
The first step has
been to learn what kinds of compounds the fungus makes naturally on its own.
“We just don’t know much about some of the compounds, so we need to do research
on their ignition chemistry and how they behave in an engine,” Taatjes said. The
team, he says, is working with Professor William H. Green at the Massachusetts
Institute of Technology to develop an ignition chemistry model that can predict
the performance of the classes of compounds made by the fungus.
Combustion expert Craig Taatjes adjusts a multiplexed chemical kinetics reactor at the Advanced Light Source at Lawrence Berkeley National Laboratory. Sandia’s unique machine probes individual chemical reactions with isomeric resolution. Experiments on this machine will help examine the fundamental autoignition chemistry of potential new biofuels. (Image by Dino Vournas) |
Hadi and his
colleagues are doing their part to build up the understanding of the
distribution of molecules produced by the various fungi, at which point they
can genetically tailor them to produce more of the “right” kinds of compounds
that suit the needs of engine combustion.
Eventually, the team
anticipates that enough hydrocarbons will be extracted from those produced by
the fungus to test in the lab, or even in an engine. “We hope, in the end, to
have a biofuel that was developed in conjunction with the development of the
combustion model for that biofuel,” Taatjes said.
Dec, who runs the
Homogeneous-Charge Compression Ignition (HCCI) lab at Sandia, said experiments
on the HCCI platform offer good fundamental information on fuel auto-ignition
behavior that can be related to performance in other engine types, such as
spark-ignition or diesel, as well as to performance in HCCI engines.
Engine, biofuels
collaboration a no-brainer
Taatjes, Dec and Hadi all agree that it makes perfect sense for Sandia to
invest in a project that focuses on an engine’s interaction with a new biofuel.
“Any fuel that’s
going to make it in the marketplace is going to have to blend with gasoline,”
Dec said. “A new biofuel, whether it comes from the Ascocoryne fungus or another source, will be more useful
commercially if we have first learned how it will affect combustion processes,”
Hadi added.
Another aspect of
this project, Taatjes said, is that the biofuels researchers are working
directly with the combustion experts to understand from the start just what
will work best as fuel for internal combustion engines, accelerating the pace
of alternative fuel development and the associated engine optimization. “We
have a rare opportunity to decide ourselves what the fuel is going to look like
and can build our own optimization loop,” he said.
“There is a whole new
range of potential fuels now with biomass,” Dec said. “The new fuels will
have to work well with both existing engines and advanced engines, like HCCI or
low-temperature diesel combustion. Only then will you be able to sell the fuel
at the pump and get your new high-efficiency, low-emissions engine into the
marketplace.”
