[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.]
MIT team engineers yeast to boost lipid production for biofuels
January 20, 2017
MIT engineers have genetically engineered strains of the oleaginous yeast Yarrowia lipolytica to boost the production of lipids by about 25% compared to previously engineered yeast strains. Their approach could enable commercialization of microbial carbohydrate-based lipid production, supporting the renewable production of high-energy fuels such as diesel.
A paper on their work is published in the journal Nature Biotechnology; the MIT team, led by Gregory Stephanopoulos, the Willard Henry Dow Professor of Chemical Engineering and Biotechnology at MIT, is now working on additional improvements to the lipids yield.
UC Irvine team discovers nitrogenase Fe protein can reduce CO2 to CO; implications for biofuel production
December 28, 2016
A team at the University of California, Irvine has discovered that the iron protein (the reductase component) of the natural enzyme nitrogenase can, independent of its natural catalytic partner, convert CO2 to carbon monoxide (CO)—a syngas used to produce useful biofuels and other chemical products.
The team, led by Professor Yilin Hu (Molecular Biology and Biochemistry), also found that they could express the reductase component alone in the soil bacterium Azotobacter vinelandii to convert CO2 in a manner more applicable to large-scale production of CO. This whole-cell system could be explored further for new ways of recycling atmospheric CO2 into biofuels and other commercial chemical products. A paper on their work is published in the journal Nature Chemical Biology.
UW-Madison and GLBRC team engineers S. cerevisiae to ferment xylose, nearly doubling efficiency of converting biomass sugars to biofuel
October 15, 2016
Scientists at the University of Wisconsin-Madison and the Great Lakes Bioenergy Research Center (GLBRC) have used directed evolution to nearly double the efficiency with which the commonly used industrial yeast Saccharomyces cerevisiae converts plant sugars to biofuel. The resulting improved yeast could boost the economics of making ethanol, specialty biofuels and bioproducts.
S. cerevisiae poses a challenge to researchers using it to make biofuel from cellulosic biomass such as grasses, woods, or the nonfood portion of plants. Although the microbe is highly adept at converting a plant’s glucose to biofuel, it ignores the plant’s xylose, a five-carbon sugar that can make up nearly half of all available biomass sugars.
Researchers show mixotrophic fermentation process improves carbon conversion, boosting yields and reducing CO2
October 03, 2016
A team from White Dog Labs, a startup commercializing a mixotrophy-based fermentation process, and the University of Delaware have shown that anaerobic, non-photosynthetic mixotrophy—the concurrent utilization of organic (for example, sugars) and inorganic (CO2) substrates in a single organism—can overcome the loss of carbon to CO2 during fermentation to increase product yields and reduce overall CO2 emissions.
In an open-access paper published in Nature Communications, the researchers report on their engineering of the bacterium Clostridium ljungdahlii to produce acetone with a mass yield 138% of the previous theoretical maximum using a high cell density continuous fermentation process. In addition, when enough reductant (i.e., H2) was provided, the fermentation emitted no CO2. They further showed that mixotrophy is a general trait among acetogens.
Toyota develops new DNA analysis technology to accelerate plant improvement; boosting biofuel crop yield
September 23, 2016
Toyota Motor Corporation (TMC) has developed a DNA analysis technology it calls Genotyping by Random Amplicon Sequencing (GRAS). This technology is capable of significantly improving the efficiency of identifying and selecting useful genetic information for agricultural plant improvement.
This newly developed technology could thus lead to substantial time and cost savings in the agricultural plant improvement process. Toyota says that the promising technology has the potential to boost sugar-cane production, and to increase biofuel crop yields per unit area of land. The company worked with analytical materials provided by the Kyushu Okinawa Agricultural Research Center (KARC) of the National Agriculture and Food Research Organization (NARO)
Researchers generate methane from CO2 in one light-driven step using engineered bacteria
August 25, 2016
Using an engineered strain of the phototropic bacterium Rhodopseudomonas palustris as a biocatalyst, a team from the University of Washington, Utah State University and Virginia Polytechnic Institute and State University have reduced carbon dioxide to methane in one enzymatic step.
The work demonstrates the feasibility of using microbes to generate hydrocarbons (i.e., CH4 in this case) from CO2 in one enzymatic step using light energy. A paper on their work is published in Proceedings of the National Academy of Sciences (PNAS).
U Florida team using fungi to extract cobalt and lithium from waste batteries
August 22, 2016
A team of researchers University of South Florida is using naturally occurring fungi to drive an environmentally friendly recycling process to extract cobalt and lithium from tons of waste batteries. The researchers presented their work at the 252nd National Meeting & Exposition of the American Chemical Society (ACS) in Philadelphia.
Although a global problem, the US leads the way as the largest generator of electronic waste. It is unclear how many electronic products are recycled. Most likely, many head to a landfill to slowly break down in the environment or go to an incinerator to be burned, generating potentially toxic air emissions.
New genome sequences target next generation of yeasts with improved biotech uses
August 16, 2016
Metabolically, genetically and biochemically, yeasts (unicellular fungi) are highly diverse; more than 1,500 yeast species have been identified. Characteristics such as thick cell walls and tolerance of pressure changes that could rupture other cells mean yeasts are easily scaled up for industrial processes. In addition, they are easy to grow and modify and, with notable exceptions such as Candida albicans, most are not associated with human illness. While these capabilities can be used for a wide range of biotechnological applications, including biofuel production, so far industry has only harnessed a fraction of the diversity available among yeast species.
To help boost the use of a wider range of yeasts and to explore the use of genes and pathways encoded in their genomes, a team led by researchers at the US Department of Energy Joint Genome Institute (DOE JGI), a DOE Office of Science User Facility at Lawrence Berkeley National Laboratory, conducted a comparative genomic analysis of 29 yeasts, including 16 whose genomes were newly sequenced and annotated. In a study being published this week in the Proceedings of the National Academy of Sciences (PNAS), the team mapped various metabolic pathways to yeast growth profiles.
MIT, Novogy team engineers microbes for competitive advantage in industrial fermentation; the ROBUST strategy
August 06, 2016
Researchers at MIT and startup Novogy have engineered bacteria and yeast (Escherichia coli, Saccharomyces cerevisiae and Yarrowia lipolytica) used as producer microbes in biofuel production to use rare compounds as sources of nutrients. The technique, described in a paper in the journal Science, provides the producer microbes with competitive advantage over other, contaminating microbes with minimal external risks, given that engineered biocatalysts only have improved fitness within the customized fermentation environment.
Ethanol is toxic to most microorganisms other than the yeast used to produce it, naturally preventing contamination of the fermentation process. However, this is not the case for the more advanced biofuels and biochemicals under development. Thus, one problem facing the production of advanced biofuels via large-scale fermentation of complex low-cost feedstocks (e.g., sugarcane or dry-milled corn) is the contamination of fermentation vessels with other, unwanted microbes that can outcompete the designated producer microbes for nutrients, reducing yield and productivity.
New hybrid sweetgum trees could boost paper, bioenergy production
July 14, 2016
Researchers at the University of Georgia (UGA) have crossed American sweetgums with their Chinese cousins, creating hybrid sweetgum trees that have a better growth rate and denser wood than natives, and can produce fiber year-round. The hybrid sweetgum trees have enormous potential for the production of bioenergy and paper, said Scott Merkle, a professor in UGA’s Warnell School of Forestry and Natural Resources.
Sweetgum trees thrive under diverse conditions, grow as fast as pine trees and provide the type of fiber needed for specialty papers-and they’ve long been desired by paper and bioenergy producers. However, harvesting mature sweetgums can often be too costly or even ill-advised because they typically grow the best on the edges of swamps and in river bottoms, which are often inaccessible during the wet winter months.
Bochum team engineers artificial hydrogenase for hydrogen production; targeting foundation for industrial manufacturing
June 01, 2016
Researchers at Ruhr-Universität Bochum (RUB) have engineered a hydrogen-producing enzyme in the test tube that works as efficiently as the original. The protein—a hydrogenase from green algae ( [FeFe]-hydrogenase HYDA1 from Chlamydomonas reinhardtii)—is made up of a protein scaffold and a cofactor.
The researchers have been investigating mechanisms of hydrogen biocatalysis for a number of years. In 2013, the team reported developing semi-synthetic hydrogenases by adding the protein’s biological precursor to a chemically synthesized inactive iron complex.
JBEI, UCSD scientists develop systems biology-based workflow to improve biofuels productivity
May 21, 2016
Researchers at the US Department of Energy (DOE)’s Joint BioEnergy Institute (JBEI), in collaboration with researchers at the University of California, San Diego, have developed a workflow that integrates various “omics” data and genome-scale models to study the effects of biofuel production in a microbial host.
The development of omics technologies, such as metabolomics and proteomics, and systems biology have significantly enhanced the ability to understand biological phenomena. Nevertheless, the interpretation of large omics data into meaningful “knowledge” as well as the understanding of complex metabolic interactions in engineered microbes remains challenging. This new open-source workflow—which integrates various omics data and genome-scale models—drives the transition from vision to conception of a designed working phenotype.
New renewable hydrocarbon fuel pathway uses platform molecule acetoin produced by biomass fermentation
March 30, 2016
Researchers at Nanjing Tech University in China have developed a new pathway for the production of liquid hydrocarbon fuels from lignocellulose. The new Nanjing Tech process uses acetoin—a novel C4 platform molecule derived from new ABE (acetoin–butanol–ethanol)-type fermentation via metabolic engineering—as a bio-based building block for the production of the liquid hydrocarbon fuels.
In a paper published in the RSC journal Green Chemistry, the Nanjing Tech team reported producing a series of diesel or jet fuel range C9–C14 straight, branched, or cyclic alkanes in excellent yields by means of C–C coupling followed by hydrodeoxygenation reactions.
Biodiesel from engineered sugarcane more economical than from soybean
March 18, 2016
A techno-economic analysis by a team from the University of Illinois at Urbana Champaign and Virginia Polytechnic Institute and State University has determined that biodiesel produced from oil from genetically modified lipid-producing sugarcane (lipid-cane) is much more economical than biodiesel produced from soybean oil.
In their open-access paper, published in the journal Biofuels, Bioproducts & Biorefining, the researchers reported results showing that the biodiesel production cost from lipid-cane decreased from $0.89/L to $0.59 /L as the lipid content in the cane increased from 2 to 20%; this cost was lower than that obtained for soybeans ($1.08/L).
Berkeley Lab researchers devise new technique to reduce lignin and increase sugar yields; lowering biomass pretreatment costs
February 25, 2016
Scientists from the US Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and Joint BioEnergy Institute have devised a new strategy for reducing lignin in plants by modifying a key metabolic entrypoint for the synthesis of the most important lignin monomers.
The new technique, reported in an open-access paper in the journal Plant & Cell Physiology, could help lower the cost of converting biomass into lower carbon biofuels and bio-products.
Newly identified enzymes from herbivore gut fungi may lead to cheaper cellulosic biofuels
February 19, 2016
A team of researchers led by Dr. Michelle O’Malley at UC Santa Barbara has identified several promising new enzyme candidates for breaking down lignocellulsoic biomass for biofuel production from relatively unexplored gut fungi in herbivores. To do so, they developed a systems-level approach that integrates transcriptomic sequencing (RNA-Seq); proteomics; phenotype; and biochemical studies.
The biomass-degrading enzymes from the anaerobic gut fungi are competitive with optimized commercial enzyme preparations from Aspergillus and Trichoderma. Further, compared to the model platforms, the gut fungal enzymes are unbiased in substrate preference due to a wealth of xylan-degrading enzymes. The findings suggest that industry could modify the gut fungi so that they produce improved enzymes that will outperform the best available ones, potentially leading to cheaper biofuels and bio-based products. A paper on their work is published in the journal Science.
Wisconsin, GLBRC researchers use chemical genomics to engineer IL-resistant yeast to improve biofuel production
February 14, 2016
Researchers at the University of Wisconsin-Madison and the Great Lakes Bioenergy Research Center (GLBRC) and colleagues have engineered a new strain of the yeast S. cerevisiae that is more resistant to the toxic effects of ionic liquids (ILs) used to generate sugars from lignocellulose.
As a result, their xylose-converting strain consumed glucose and xylose faster and produced more ethanol than the wild type strain. The development could improve the efficiency of making fuel from cellulosic biomass such as switchgrass. The work is reported in an open-access paper in the journal Microbial Cell Factories.
NREL and BESC discovery explains higher biomass degrading activity of C. thermocellum; potential boon for cellulosic biofuels
February 06, 2016
Researchers at the Energy Department’s National Renewable Energy Laboratory (NREL) and the BioEnergy Science Center (BESC) have discovered a new cell-free cellulosomal system in Clostridium thermocellum—the most efficient single biomass degrader characterized to date —that is not tethered to the bacterial cell wall and is independent of the primary (tethered) cellulosomes.
Their discovery was made during an investigation into the performance of C. thermocellum. The scientists found the microorganism utilizes the common cellulase degradation mechanisms known today (free enzymes and scaffolded enzymes—i.e., a structured architecture of enzymes—attached to the cell), and a new category of scaffolded enzymes not attached to the cell. Reported in an open-access paper in Science Advances, the finding could lead to cheaper production of cellulosic ethanol and other advanced biofuels.
UCR team advances direct production of chemical and fuel precursors in yeast
January 28, 2016
A team led by a researcher at the University of California, Riverside has adapted the CRISPR-Cas9 gene editing system for use in a yeast strain that can produce useful lipids and polymers. The development will lead to new precursors for biofuels, specialty polymers, adhesives and fragrances.
Published recently in an open-access paper in the journal ACS Synthetic Biology, the research involves the oleaginous (oil-producing) yeast Yarrowia lipolytica, which is known for converting sugars to lipids and hydrocarbons that are difficult to make synthetically. Until now, Y. lipolytica has been hard to manipulate at the genetic level, but the application of CRISPR-Cas9 will change that, allowing scientists to tap into its bio-manufacturing potential.