Thursday, October 27, 2011

Researchers produce cheap sugars for sustainable biofuel production

Iowa State University's Robert C. Brown keeps a small vial of brown, sweet-smelling liquid on his office table.

"It looks like something you could pour on your pancakes," he said. "In many respects, it is similar to molasses."

Brown, in fact, calls it "pyrolytic molasses."

That's because it was produced by the fast of biomass such as corn stalks or . Fast pyrolysis involves quickly heating the biomass without oxygen to produce liquid or gas products.

"We think this is a new way to make inexpensive sugars from biomass," said Brown, an Anson Marston Distinguished Professor in Engineering, the Gary and Donna Hoover Chair in Mechanical Engineering and the Iowa Farm Bureau Director of Iowa State's Bioeconomy Institute.

That's a big deal because those sugars can be further processed into biofuels. Brown and other Iowa State researchers believe pyrolysis of lignocelluslosic biomass has the potential to be the cheapest way to produce biofuels or biorenewable chemicals.

Brown and Iowa State researchers will present their ideas and findings during tcbiomass2011, the International Conference on Thermochemical Conversion Science in Chicago Sept. 28-30. On Thursday, Sept, 29, Brown will address the conference with a plenary talk describing how large amounts of sugars can be produced from biomass by a simple pretreatment before pyrolysis. He'll also explain how these sugars can be economically recovered from the products of pyrolysis.

A poster session following Brown's talk will highlight thermochemical technologies developed by 19 Iowa State research teams, including processes that:
increase the yield of sugar from fast pyrolysis of biomass with a pretreatment that neutralizes naturally occurring that otherwise interferes with the release of sugarsprevent burning of sugar released during pyrolysis by rapidly transporting it out of the hot reaction zonerecover sugar from the heavy end of bio-oil that has been separated into various fractionsseparate sugars from the heavy fractions of bio-oil using a simple water-washing process.In addition to Brown, key contributors to the pyrolysis research at Iowa State include Brent Shanks, the Mike and Jean Steffenson Professor of Chemical and Biological Engineering and director of the National Science Foundation Engineering Research Center for Biorenewable Chemicals based at Iowa State; Christopher Williams, professor of civil, construction and environmental engineering; Zhiyou Wen, associate professor of food science and human nutrition; Laura Jarboe, assistant professor of chemical and biological engineering; Xianglan Bai, adjunct assistant professor of aerospace engineering; Marjorie Rover and Sunitha Sadula, research scientists at the Center for Sustainable Environmental Technologies; Dustin Dalluge, a graduate student in mechanical engineering; and Najeeb Kuzhiyil, a former doctoral student who is now working for GE Transportation in Erie, Penn.

Their work has been supported by the eight-year, $22.5 million ConocoPhillips Biofuels Program at Iowa State. The program was launched in April 2007.

Brown said Iowa State will – literally – take a bus load of students and researchers to the Chicago conference to present their work on thermochemical technologies, including production of sugars from biomass.

"The Department of Energy has been working for 35 years to get sugar out of biomass," Brown said. "Most of the focus has been on use of enzymes, which remains extremely expensive. What we've developed is a simpler method based on the heating of ."

Provided by Iowa State University (news : web)

New technology enables molecular-level insight into carbon sequestration


Flaviu Turcu co-invented a novel NMR system for carbon sequestration research applications with EMSL staff, David Hoyt (Principal Investigator) and Jesse Sears, and PNNL colleagues, Jian Zhi Hu and Kevin Rosso. Turcu, pictured above, holds the high-pressure MAS rotor and stands behind the high-pressure rotor loading reaction chamber pieces of the system.

Carbon sequestration is a potential solution for reducing greenhouse gases that contribute to climate change, but its scientific challenges are complex. Analytical tools are needed that provide information about the mineral-fluid interactions of carbon dioxide (CO2) at the molecular level.

As part of Pacific Northwest National Laboratory (PNNL)'s Carbon Sequestration Initiative, a team of EMSL and PNNL researchers developed and patented such a tool—a unique high-pressure magic angle spinning (MAS) nuclear magnetic resonance (NMR) capability that operates in conditions characteristic of geologic carbon sequestration.

Described in the September 2011 issue of the Journal of Magnetic Resonance, this new technology consists of a reusable high-pressure MAS rotor, a high-pressure rotor loading/reaction chamber for in situ sealing and reopening of the high-pressure MAS rotor, and a MAS probe with a localized radiofrequency coil for background signal suppression.

This new capability can help determine reaction intermediates and final products that occur during mineral dissolution reactions relevant to the geologic disposal of CO2, as these researchers reported in the July 2011 issue of the International Journal of Greenhouse Gas Control.

Identifying reaction intermediates is not possible using only ex situ measurements and is critical to determining the mechanisms of mineral dissolution at high pressures. This new capability has the potential to further the exploration of solid-state chemistry at new levels of high pressure and temperature in many science areas.

More information: References: Hoyt DW, RVF Turcu, JA Sears, KM Rosso, SD Burton, AR Felmy, and JZ Hu. 2011. “High-pressure Magic Angle Spinning Nuclear Magnetic Resonance,” Journal of Magnetic Resonance, DOI:10.1016/j.jmr.2011.07.019

Hoyt DW, JA Sears, RVF Turcu, KM Rosso, and JZ Hu. 2011. U.S. Patent submission E-16894, “Devices and Process for High-Pressure Magic Angle Spinning Nuclear Magnetic Resonance,” filed July 28, 2011 (provisional patent submitted December 13, 2010).

Kwak JH, JZ Hu, RVF Turcu, KM Rosso, ES Ilton, C Wang, JA Sears, MH Engelhard, AR Felmy, and DW Hoyt. 2011. "The Role of H2O in the Carbonation of Forsterite in Supercritical CO2." International Journal of Greenhouse Gas Control 5:1081-1092.

Provided by Environmental Molecular Sciences Laboratory (news : web)

Understanding lethal synthesis

The chemical reaction which makes some poisonous plants so deadly has been described by researchers at the University of Bristol in a paper published today in Angewandte Chemie.

Professor Adrian Mulholland in the School of Chemistry and colleagues successfully analyzed why a particular toxic product originating from sodium fluoroacetate (a colourless salt used as a rat poison) is formed in an enzyme.

Professor Mulholland said: “The reaction could go in one of two ways, and only one of those two makes a poison.  The difference is very subtle, just in terms of which one of two hydrogen atoms is removed by the enzyme in the reaction.

 “This process gives rise to 'lethal synthesis', that is where something non-toxic is converted into a poison in the body.  It is responsible for the lethal toxicity of fluoroacetate to humans and other mammals and explains, for example, why plants such as gifblaar in South Africa and Gastrolobium bilobum (heart-leaved poison) in Australia kill sheep and cattle, and why ‘1080’ is such a potent rat poison.”

The Bristol team used high-level quantum mechanics/molecular mechanics (QM/MM) modelling to successfully explain how the enzyme citrate synthase (CS) converts fluoroacetyl-CoA from fluoroacetate to fluoricitrate, which is what makes fluoroacetate toxic.  Only the particular form of fluorocitrate made by the enzyme is poisonous; if it made the mirror image molecule instead, the result would not be a poison.  The Bristol team’s calculations show why the enzyme produces this form.

CS performs the first reaction in the citric acid cycle, a series of enzyme-catalysed which is of central importance in all living cells.  In this reaction, citrate, a six-carbon compound, is formed from a two-carbon acetate in the form of acetyl-CoA and the four-carbon acceptor compound oxaloacetate.

However, if fluoroacetyl-CoA from fluoroacetate is present instead of acetyl-CoA, fluorocitrate is formed.  The particular form (isomer) of fluorocitrate, and only this isomer, goes on to react with and inhibit (block) aconitase, the next enzyme in the citric acid cycle.  This causes citrate to build-up in tissue and blood, turning off most of the energy supply to cells and resulting in tissue damage and death.

By explaining the conversion of fluoroacetyl-CoA to fluorocitrate by CS, the Bristol research has shed light on an archetypal selectivity problem.  Greater understanding of such problems could assist the prediction of selectivity in enzyme-catalyzed reactions which has potential practical applications in catalyst design and drug metabolism.

The research is published today in , the journal of the German Chemical Society.  The study has been classed as a Very Important Paper (VIP) according to the evaluation of three referees.

More information: “Lethal Synthesis” of Fluorocitrate by Citrate Synthase Explained through QM/MM Modeling’ by Marc W. van der Kamp, John D. McGeagh, and Adrian J. Mulholland in Angewandte Chemie. http://onlinelibra … 0.1002/(ISSN)1521-3773/

Provided by University of Bristol (news : web)

NASA scientist unveils new chemical detection technology

 NASA scientists are creating technology that can detect hazardous chemical compounds in the air with a smart phone.

Jing Li, a physical scientist at NASA's Ames Research Center, Moffett Field, Calif., demonstrated this called Cell-All in a training exercise on Sept. 28, 2011, at the Los Angeles Fire Department, Los Angeles.

The technology was used to detect carbon monoxide in a response and rescue training exercise for Los Angeles fire and . The U.S. Department of Homeland Security's Science and Technology (S&T) Directorate, in partnership with the Los Angeles Fire Department, Los Angeles Police Department and the California Environmental Protection Agency, sponsored the training exercise.

"This new technology can enhance both personal and public safety by utilizing a common device, such as a cell phone, to detect hazardous chemicals," said Stephen Dennis, technical director of S&T’s Homeland Security Advanced Research Projects Agency. "Our goal is to create a lightweight, cost-effective, power-efficient resource for widespread public use."

The Cell-All technology, consisting of an energy-efficient sensor and cell phone application, detects toxic chemicals and alerts individuals and public safety authorities. Users have the option of using the sensor in a personal mode, which provides personal alerts, or opting-in to a network service, providing anonymous reports of the environmental condition to local responder networks.

Two different prototypes of Cell-All were demonstrated: one developed by NASA’s Center for Nanotechnology at Ames and a prototype developed in partnership between Qualcomm Inc., San Diego, Calif. and Synkera Technologies Inc., Longmont, Colo.

To see images of the cell phone sensors, visit: http://www.nasa.go … sensors.html

Provided by JPL/NASA (news : web)