© Université de Lausanne
Consolidated bio-processing - converting pretreated biomass in one step to a renewable fuel, eliminating the two-step procedure of using acids or enzymes to extract sugars, and then fermenting sugars into fuel - is considered a critical path element in driving down the costs of cellulosic biofuel towards cost parity with gasoline, and has been widely described as "the holy grail of biofuels".
The particular breakthrough here is that - to this point, the small number of companies that have developed an organism capable of CBP - most notably, Mascoma and Qteros - have been working with ethanol as a target fuel.
In the announcement, the research team has been able to achieve a one-step process to create a renewable drop-in fuel - at this point, renewable diesel - that would require no change in distribution or vehicle infrastructure to be deployed in the transportation fleet.
The work is the subject of an article published in today's edition of Nature, featuring work by by LS9 scientists Zhihao Hu, Andreas Schirmer, Amy McClure, and Stephen del Cardayre, and the U.C. Berkeley and JBEI team of Eric Stein, Yisheng Kang, Gregory Bokinsky and Jay Keasling. The paper is entitled: "Microbial production of fatty acid-derived fuels and chemicals from plant biomass."
"We incorporated genes that enabled production of biodiesel directly," JBEI CEO Jay Keasling explained in an email published by AFP. "The engineered E. coli secretes the biodiesel from the cell, which means that we don't need to break open the cell to get the diesel out. This saves substantially on processing cost. In addition, "the biodiesel is insoluble in water, which means that it forms a separate phase when it is secreted from the engineered E. coli - it floats to the top as any oil would. This also saves on processing costs."
"The work was done in the JBEI facility through a grant from LS9 and the UC Discovery Grant Program," added Jay Keasling in a note to Biofuels Digest, and tantalizingly added, "Much more to come. Stay tuned ..."
The UC Discovery Grant program is a three-way partnership between the University of California, private industry and the state of California that is aimed at strengthening and expanding California's economy through targeted fields of research. JBEI is one of three Bioenergy Research Centers funded by DOE to advance the development of advanced biofuels, and is a partnership between Lawrence Berkeley National Laboratory, the Sandia National Laboratories, the University of California campuses of Berkeley and Davis, the Carnegie Institution for Science at Stanford University, and the Lawrence Livermore National Laboratory.
LS9 was recently elevated to #8 in the 50 Hottest Companies in Bioenergy for its first-generation platform, in which the company has pioneered the production of renewable diesel, renewable jet fuel, and renewable chemicals, using sugar juices as a feedstock. Companies producing renewable diesel and other drop-in fuels have received close attention from the Digest readership and international selector panel in this year's rankings, with Amyris reaching #3 worldwide for its microbial conversion system, while Virent was ranked in the top 30 for its (non-microbial) bioforming system that also produces drop-in fuels from biomass.
The announcement of a second-generation process for LS9 does not directly affect development of its first generation technologies, work that is continuing with partners Proctor & Gamble and Chevron, according to the company's VP for R&D, Stephen del Cardayre. "But this breakthrough is a significant step toward the development of scalable, low-cost drop in compatible cellulosic fuels and chemicals," added del Cardayre "What's new is that we now have a pathway towards producing fuels from hemicellulose rather than sugarcane juices. It broadens our entire range of options."
The team of scientific collaborators that included LS9 scientists Zhihao Hu, Andreas Schirmer, Amy McClure, and Stephen del Cardayre, and the U.C. Berkeley and JBEI team of Eric Steen, Yisheng Kang, Gregory Bokinsky and Jay Keasling, have published the results of this research in the January 28, 2010 edition of the journal Nature.
The combination of E. coli with new biochemical reactions realized through synthetic biology, enabled Keasling, Steen and their colleagues to produce structurally tailored fatty esters (biodiesel), alcohols and waxes directly from simple sugars.
"Biosynthesis of microbial fatty acids produces fatty acids bound to a carrier protein, the accumulation of which inhibits the making of additional fatty acids," Steen says. "Normally E. coli doesn't waste energy making excess fat, but by cleaving fatty acids from their carrier proteins, we're able to unlock the natural regulation and make an abundance of fatty acids that can be converted into a number of valuable products. Further, we engineered our E. coli to no longer eat fatty acids or use them for energy."
After successfully diverting fatty acid metabolism toward the production of fuels and other chemicals from glucose, the JBEI researchers engineered their new strain of E. coli to produce hemicellulases - enzymes that are able to ferment hemicellulose, the complex sugars that are a major constituent of cellulosic biomass and a prime repository for the energy locked within plant cell walls.
"This was truly a team effort that demonstrates the strength of combining academic, government, and industrial efforts and the importance of grant programs, such as the UC Discovery Grant, which support them," added Keasling, while del Cardayre added, "it's really a model going forward about de-risking the discovery process through collaboration, to the point where commercial companies like LS9 can take it forward to develop advanced biofuels for the market."
Both Keasling and del Cardayre confirmed that additional articles and additional announcements are expected this year from the collaboration between LS9 and JBEI.
In addition, LS9 is expected to move into its new 2.5 Mgy demonstration-scale facility in the next month, and additional major announcements have been rumored regarding the company's first generation technologies. The company currently has a 1,000 liter pilot facility in South San Francisco.
LS9 CEO Bill Haywood is expected to be among the panelists at the upcoming Stanford-MIT VLAB forum on biofuels that will take place in Palo Alto on February 16th; Biofuels DIgest editor Jim Lane will be moderating the event and we can expect to explore the implications of the new platform, as well as advances in LS9′s first-generation of technologies, at that event.
"The increased demand and limited supply of these oils has resulted in competition with food, higher prices, questionable land-use practices and environmental concerns associated with their production," Keasling said. "A more scalable, controllable, and economic alternative route to these fuels and chemicals would be through the microbial conversion of renewable feedstocks, such as biomass-derived carbohydrates."
"Productivity, titer and efficient conversion of feedstock into fuelare the three most important factors for engineering microbes that can produce biofuels on an industrial scale," researcher Eric Steen added. "There is still much more research to do before this process becomes commercially feasible."
Reader Comments
to our Newsletter