[Due to the increasing size of the archives, each topic page now contains only the prior 365 days of content. Access to older stories is now solely through the Monthly Archive pages or the site search function.]
Researchers engineer new pathway in E. coli to produce renewable propane
April 15, 2015
Researchers at The University of Manchester, Imperial College London and University of Turku have made an advance toward the renewable biosynthesis of propane with the creation of a new synthetic pathway in E. coli, based on a fermentative butanol pathway. An open access paper on the work is published in the journal Biotechnology for Biofuels.
In 2014, members of the team from Imperial College and the University of Turku had devised a synthetic metabolic pathway for producing renewable propane from engineered E. coli bacteria, using pathways based on fatty acid synthesis. (Earlier post.) Although the initial yields were far too low for commercialization, the team was able to identify and to add essential biochemical components in order to boost the biosynthesis reaction, enabling the E. coli strain to increase propane yield. Yields, however, were still too low.
New engineered metabolic pathways in yeast enable efficient fermentation of xylose from biomass
March 05, 2015
Researchers with the Energy Biosciences Institute (EBI), a partnership that includes Berkeley Lab and the University of California (UC) Berkeley, have introduced new metabolic pathways from the fungus Neurospora crassa into the yeast Saccharomyces cerevisiae to increase the fermentative production of fuels and other chemicals from biomass. An open access paper on the work is publised in the journal eLife.
While S. cerevisiae is the industry mainstay for fermenting sugar from cornstarch and sugarcane into ethanol, it requires substantial engineering to ferment sugars derived from plant cell walls such as cellobiose and xylose. The new metabolic pathways enable the yeast to ferment sugars from both cellulose (glucose) and hemicellulose (xylose)—the two major families of sugar found in the plant cell wall—efficiently, without the need of environmentally harsh pre-treatments or expensive enzyme cocktails.
Engineered yeast produces ethanol from three important cellulosic biomass components simultaneously; higher yields, lower cost
February 11, 2015
A team led by researchers from the University of Illinois at Urbana−Champaign has, for the first time, integrated the fermentation pathways of both hexose and pentose sugars from biomass as well as an acetic acid reduction pathway into one strain of the yeast Saccharomyces cerevisiae using synthetic biology and metabolic engineering approaches.
The engineered strain co-utilized cellobiose, xylose, and acetic acid to produce ethanol with a substantially higher yield and productivity than the control strains. The results showed the unique synergistic effects of pathway coexpression, the team reported in a paper in the journal ACS Synthetic Biology.
Researchers discover bacteria could be rich source of terpenes
December 24, 2014
Researchers at Kitasato University in Japan, Brown University in the US, and colleagues in Japan have found that bacteria could be a rich source of terpenes—natural compounds common in plants and fungi that can be used to make drugs, food additives, perfumes, and other products, including advanced fuels (earlier post, earlier post).
Terpenes are responsible for the essential oils of plants and the resins of trees. Since the discovery of terpenes more than 150 years ago, scientists have isolated some 50,000 different terpene compounds derived from plants and fungi. Bacteria and other microorganisms are known to make terpenes too, but they’ve received much less study. The new research, published in an open access paper in the Proceedings of the National Academy of Sciences, shows that the genetic capacity of bacteria to make terpenes is widespread.
DOE JBEI team boosts methyl ketone production from E. coli 160-fold; advanced biofuel or blendstock
December 02, 2014
In 2012, researchers at the US Department of Energy’s Joint BioEnergy Institute (JBEI) engineered Escherichia coli (E. coli) bacteria to overproduce from glucose saturated and monounsaturated aliphatic methyl ketones in the C11 to C15 (diesel) range from glucose. In subsequent tests, these methyl ketones yielded high cetane numbers, making them promising candidates for the production of advanced biofuels or blendstocks. (Earlier post.)
Now, after further genetic modifications of the bacteria, they have managed to boost the E.coli’s methyl ketone production 160-fold. A paper describing this work is published in the journal Metabolic Engineering.
Researchers successfully engineer E. coli to produce renewable propane; proof-of-concept
September 03, 2014
Researchers from the University of Turku in Finland, Imperial College London and University College London have devised a synthetic metabolic pathway for producing renewable propane from engineered E. coli bacteria. Propane, which has an existing global market for applications including engine fuels and heating, is currently produced as a by-product during natural gas processing and petroleum refining. A paper on their work is published in Nature Communications.
The new pathway is based on a thioesterase specific for butyryl-acyl carrier protein (ACP), which allows native fatty acid biosynthesis of the Escherichia coli host to be redirected towards a synthetic alkane pathway. Although the initial yields were low, the team was able to identify and to add essential biochemical components in order to boost the biosynthesis reaction, enabling a the E. coli strain to increase propane yield, although the amounts are still far too low for commercialization.
UGA-led team engineers bacterium for the direct conversion of unpretreated biomass to ethanol
June 03, 2014
A team led by Dr. Janet Westpheling at the University of Georgia has engineered the thermophilic, anaerobic, cellulolytic bacterium Caldicellulosiruptor bescii, which in the wild efficiently uses un-pretreated biomass—to produce ethanol from biomass without pre-treatment of the feedstock. A paper on the work is published in Proceedings of the National Academy of Sciences (PNAS).
In January, Dr. Westpheling and her colleagues reported in the journal Science their discovery that an enzyme (the cellulase CelA) from C. besciia can digest cellulose almost twice as fast as Cel7A, the current leading component cellulase enzyme on the market. (Earlier post.)