"We have been charged to develop the next generation of cellulosic biofuels. When we successfully supply sources of energy to the grid from non-food, cellulosic, parts of plants we will mitigate the food versus fuel debate," says Tim Donohue of the University of Wisconsin, Madison, one of two directors of Department of Energy Bioenergy Research Centers who spoke today in a session at the meeting.
When it comes to alternative fuels, currently ethanol is king. Almost all ethanol produced in the United States is fermented from readily available sugars in corn starch or corn kernels. Producing ethanol from corn has also come under much criticism lately, accused of being responsible for rising food prices.
Researchers are looking at alternate biomasses as food for microorganisms to ferment into ethanol. The most attractive are known as lignocellulosic biomass and include wood residues (including sawmill and paper mill discards), municipal paper waste, agricultural residues (including sugarcane bagasse), dedicated energy crops (like switchgrass) or the non-edible parts of corn like cobs, stalks or stover. The problem is, unlike corn starch, the sugars necessary for fermentation are trapped inside the lignocellulose part of this plant biomass. The key to ending the food versus fuel debate is unlocking the sugars trapped in cellulosic biomass.
To do that, some scientists have taken a page out of the playbook of the pharmaceutical industry. Pharmaceutical companies routinely use a process known as high throughput screening to rapidly test thousands of compounds for potential new drugs. Martin Keller at Oak Ridge National Laboratory, the DOE bioenergy research center director, and his lab have adapted the method to rapidly test poplar tree samples for their ability to give up sugars.
"We for the first time ever have developed a super-screening pipeline to handle thousands of samples. We took samples from approximately 1,300 poplar trees in the northwestern United States and used the screening pipeline to see if there was a difference in sugar release," says Keller. "Trees can be very different. Some trees can be easier to digest, even within the same species."
Keller is not sure why some poplars are more likely to give up their sugars than others. It could be genetic or the result of some environmental factor or a bit of both. They are now conducting experiments, growing poplar saplings under controlled environments to better understand.
In addition to studying the biomass itself, Keller's lab is also looking for microbes or microbial products that can help break it down into simple sugars. They are currently studying a bacterium found in a hot spring in Yellowstone known as Anaerocellum. It grows at approximately 80 degrees Celsius and is what is known as a consolidate bioprocessing microbe: It can not only break down the cellulosic biomass to sugars but ferment it to acetate and ethanol, saving time and money.
"Right now it is expensive to break down cellulosic biomass. That is why we don't have a sustainable biofuels industry. This is what we as a center are working to overcome," says Keller.
Once they have overcome that problem, there are companies ready to move forward. Andreas Schirmer from the company LS9 in South San Francisco describes a unique strategy. LS9 has engineered a proprietary microbe to produce UltraClean™ diesel in a one-step process. They have discovered a way to exploit the pathway that microbes use to make energy-rich fatty acids for the synthesis of cell membranes and energy storage compounds, and divert them for their own purposes. Inside the fermentor, the microbes and feedstock sit in water, so the oil-like fuel compounds rise to the surface and can be easily collected, much more efficiently than the energy rich distillation process necessary to produce ethanol.
Schirmer says they are currently using sugar cane as a cost-effective option and estimates an 80 percent reduction in carbon footprint compared to petroleum-based fuels.
"It is a bridge feedstock. Once second generation feedstocks come online we will be able to convert production over to them quickly and achieve even greater reductions in greenhouse gas emissions," says Schirmer.
Beside ethanol and biodiesel, researchers are also looking at producing hydrogen from renewable resources. Donohue's lab is working with purple bacteria called Rhodobacter sphaeroides that use photosynthesis to produce hydrogen from a combination of cellulosic feedstocks and sunlight. The hydrogen can then converted to electricity using fuel cells that his lab is also developing. They have completed laboratory scale prototype "microbial batteries" using the bacteria and the fuel cells in a single enclosed system that, when exposed to sunlight, produces enough electrical current to power a laptop.
"This is just a look under the hood at the types of activities that are going on in the United States to take advantage of microbial activities and deploy them to create the next generation of fuels," says Donohue.
Jim Sliwa | EurekAlert!
Two Group A Streptococcus genes linked to 'flesh-eating' bacterial infections
25.09.2017 | University of Maryland
Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden
At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
25.09.2017 | Power and Electrical Engineering
25.09.2017 | Health and Medicine
25.09.2017 | Physics and Astronomy