From Lawrence Livermore National Laboratory: “Turning the switch on biofuels”

From Lawrence Livermore National Laboratory

June 17, 2019
Anne M Stark
stark8@llnl.gov
925-422-9799

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Switchgrass is used as a biomass crop for advanced biofuel production.

Plant cell walls contain a renewable, nearly limitless supply of sugar that can be used in the production of chemicals and biofuels. However, retrieving these sugars isn’t all that easy.

Imidazolium ionic liquid (IIL) solvents are one of the best sources for extracting sugars from plants. But the sugars from IIL-treated biomass are inevitably contaminated with residual IILs that inhibit growth in bacteria and yeast, blocking biochemical production by these organisms.

Lawrence Livermore National Laboratory (LLNL) scientists and collaborators at the Joint BioEnergy Institute have identified a molecular mechanism in bacteria that can be manipulated to promote IIL tolerance, and therefore overcome a key gap in biofuel and biochemical production processes. The research appears in the Journal of Bacteriology.

“Ionic liquid toxicity is a critical roadblock in many industrial biosynthetic pathways,” said LLNL biologist Michael Thelen, lead author of the paper. “We were able to find microbes that are resistant to the cytotoxic effects.”

The team used four bacillus strains that were isolated from compost (and a mutant E. coli bacterium) and found that two of the strains and the E. coli mutant can withstand high levels of two widely used IILs.

Douglas Higgins, a postdoc working with Thelen at the time, dived into how exactly the bacteria do this. In each of the bacteria, he identified a membrane transporter, or pump, that is responsible for exporting the toxic IIL. He also found two cases in which the pump gene contained alterations in the RNA sequence of a regulatory guanidine riboswitch. Guanidine is a toxic byproduct of normal biological processes; however, cells need to get rid of it before it accumulates.

The normal, unmodified riboswitch interacts with guanidine and undergoes a conformational change, causing the pump to switch on and make the bacterial cells resistant to IILs.

“Our results demonstrate the critical roles that transporter genes and their genetic controls play in IIL tolerance in their native bacterial hosts,” Thelen said. “This is just another step in engineering IIL tolerance into industrial strains and overcoming this key gap in biofuel production.”

The results could help identify genetic engineering strategies that improve conversion of cellulosic sugars into biofuels and biochemicals in processes where a low concentration of ionic liquids surpass bacterial tolerance.

Scientists from Sandia National Laboratories and Lawrence Berkeley National Laboratory also contributed to this research.

The work is funded by the Department of Energy’s Office of Science

See the full article here .


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LLNL Campus

Operated by Lawrence Livermore National Security, LLC, for the Department of Energy’s National Nuclear Security Administration
Lawrence Livermore National Laboratory (LLNL) is an American federal research facility in Livermore, California, United States, founded by the University of California, Berkeley in 1952. A Federally Funded Research and Development Center (FFRDC), it is primarily funded by the U.S. Department of Energy (DOE) and managed and operated by Lawrence Livermore National Security, LLC (LLNS), a partnership of the University of California, Bechtel, BWX Technologies, AECOM, and Battelle Memorial Institute in affiliation with the Texas A&M University System. In 2012, the laboratory had the synthetic chemical element livermorium named after it.
LLNL is self-described as “a premier research and development institution for science and technology applied to national security.” Its principal responsibility is ensuring the safety, security and reliability of the nation’s nuclear weapons through the application of advanced science, engineering and technology. The Laboratory also applies its special expertise and multidisciplinary capabilities to preventing the proliferation and use of weapons of mass destruction, bolstering homeland security and solving other nationally important problems, including energy and environmental security, basic science and economic competitiveness.

The Laboratory is located on a one-square-mile (2.6 km2) site at the eastern edge of Livermore. It also operates a 7,000 acres (28 km2) remote experimental test site, called Site 300, situated about 15 miles (24 km) southeast of the main lab site. LLNL has an annual budget of about $1.5 billion and a staff of roughly 5,800 employees.

LLNL was established in 1952 as the University of California Radiation Laboratory at Livermore, an offshoot of the existing UC Radiation Laboratory at Berkeley. It was intended to spur innovation and provide competition to the nuclear weapon design laboratory at Los Alamos in New Mexico, home of the Manhattan Project that developed the first atomic weapons. Edward Teller and Ernest Lawrence,[2] director of the Radiation Laboratory at Berkeley, are regarded as the co-founders of the Livermore facility.

The new laboratory was sited at a former naval air station of World War II. It was already home to several UC Radiation Laboratory projects that were too large for its location in the Berkeley Hills above the UC campus, including one of the first experiments in the magnetic approach to confined thermonuclear reactions (i.e. fusion). About half an hour southeast of Berkeley, the Livermore site provided much greater security for classified projects than an urban university campus.

Lawrence tapped 32-year-old Herbert York, a former graduate student of his, to run Livermore. Under York, the Lab had four main programs: Project Sherwood (the magnetic-fusion program), Project Whitney (the weapons-design program), diagnostic weapon experiments (both for the Los Alamos and Livermore laboratories), and a basic physics program. York and the new lab embraced the Lawrence “big science” approach, tackling challenging projects with physicists, chemists, engineers, and computational scientists working together in multidisciplinary teams. Lawrence died in August 1958 and shortly after, the university’s board of regents named both laboratories for him, as the Lawrence Radiation Laboratory.

Historically, the Berkeley and Livermore laboratories have had very close relationships on research projects, business operations, and staff. The Livermore Lab was established initially as a branch of the Berkeley laboratory. The Livermore lab was not officially severed administratively from the Berkeley lab until 1971. To this day, in official planning documents and records, Lawrence Berkeley National Laboratory is designated as Site 100, Lawrence Livermore National Lab as Site 200, and LLNL’s remote test location as Site 300.[3]

The laboratory was renamed Lawrence Livermore Laboratory (LLL) in 1971. On October 1, 2007 LLNS assumed management of LLNL from the University of California, which had exclusively managed and operated the Laboratory since its inception 55 years before. The laboratory was honored in 2012 by having the synthetic chemical element livermorium named after it. The LLNS takeover of the laboratory has been controversial. In May 2013, an Alameda County jury awarded over $2.7 million to five former laboratory employees who were among 430 employees LLNS laid off during 2008.[4] The jury found that LLNS breached a contractual obligation to terminate the employees only for “reasonable cause.”[5] The five plaintiffs also have pending age discrimination claims against LLNS, which will be heard by a different jury in a separate trial.[6] There are 125 co-plaintiffs awaiting trial on similar claims against LLNS.[7] The May 2008 layoff was the first layoff at the laboratory in nearly 40 years.[6]

On March 14, 2011, the City of Livermore officially expanded the city’s boundaries to annex LLNL and move it within the city limits. The unanimous vote by the Livermore city council expanded Livermore’s southeastern boundaries to cover 15 land parcels covering 1,057 acres (4.28 km2) that comprise the LLNL site. The site was formerly an unincorporated area of Alameda County. The LLNL campus continues to be owned by the federal government.

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