Researchers engineer hardier microbes to improve bioproduction of fuels, chemicals
Posted Oct 13, 2021
Posted Oct 13, 2021
Busy, productive microbes use enzymes to break down leaves, stalks and other biomass and then convert that material into renewable fuels and chemicals. But some of those enzymes can’t function at the high temperatures or acidity that maintain low operating costs for fermentation processes.
A research team led by Iowa State University’s Laura Jarboe will try to fix that problem by identifying rougher, tougher enzymes and engineering microbes to use them in industrial fermentation. Their work is supported by a three-year, $969,000 grant from the U.S. Department of Energy.
“We want to make these microbes more robust,” said Jarboe, Iowa State’s Cargill Professor of Chemical Engineering. “To do that, we need to think about the problem for the microbes. We can’t just say, ‘Do better.’”
In this case, enzymes that require cooling or pH (acidity/alkalinity) adjustments to remain active are costly problems. Some of these enzymes are vital to the microbes’ ability to convert bio-based substrates into products, and some are vital for organism survival.
Are there hardier, tougher, more robust enzymes out there? Could industrial microbes be engineered to be more like “extremophiles” and remain active under the harsh conditions in the fermentors?
Teaming up to find answers are Jarboe; Robert Jernigan, an Iowa State Charles F. Curtiss Distinguished Professor in Agriculture and Life Sciences in the Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology; and Peter St. John, a senior scientist in the Biosciences Center at the U.S. Department of Energy’s National Renewable Energy Laboratory in Golden, Colorado.
The energy department’s Office of Biological and Environmental Research awarded 34 biotechnology grants totaling $45.5 million this summer, including this grant supporting the work of Jarboe, Jernigan and St. John. Winners were selected after a competitive, peer-review process.
“Biofuels that can power planes and ships, and bioproducts made from renewable resources will play a critical role in decarbonizing our economy,” said Secretary of Energy Jennifer M. Granholm, in a statement announcing the grants.
The energy department’s research program is targeting two areas of study: One, re-engineering microbes that help convert biomass and synthetic polymers into fuels and products. And two, developing imaging technologies to better study the plants and microbes used to produce bioproducts.
The various projects “will help us understand, predict, and even design (biofuels and bioproducts) at the cellular level, so that we can unlock their full potential,” Granholm said.
Jarboe, Jernigan and St. John have developed a three-part plan to reengineer microbes so they produce heat- and acid-resistant enzymes:
“Finding a systematic approach to engineering thermotolerance and pH-tolerance in microbes,” St. John said, “will hopefully allow newly developed strains to move from the lab to industry with greater speed and lower cost.”