Advance toward producing biofuels without
stressing global food supply
Scientists in California are reporting use of a
first-of-its-kind approach to craft genetically engineered microbes
with the much-sought ability to transform switchgrass, corn cobs, and
other organic materials into methyl halides - the raw material for
making gasoline and a host of other commercially important products.
The new bioprocess could help pave the way for producing biofuels from
agricultural waste, easing concerns about stress on the global food
supply from using corn and other food crops. Their study is scheduled
for the May 20 issue of the Journal of the American Chemical Society,
a weekly publication.
Christopher Voigt and colleagues note in the new
study that using crop waste to produce methyl halides is one of the
most attractive ways of transforming biomass into liquid fuels and
chemical raw materials now derived from petroleum. Plants and microbes
produce methyl halides naturally, but in amounts too small for
commercial use.
Using a database of 89 genes from plants, fungi,
and bacteria known to produce methyl halides, the researchers
identified genes that were the most likely to produce the highest
levels of these substances. The scientists then spliced these genes
into Brewer's yeast - used to make beer and wine - so that the yeast
cells churned out methyl halides instead of alcohol. In laboratory
studies, the two engineered microbes helped boost methyl halide
production from switchgrass, corn cob husks, sugar cane waste, and
poplar wood to levels with commercial potential. - MTS
Working on the railroad? Using concrete could
help environment
Concrete railway cross ties could
be an eco-friendly alternative to those made of wood, scientists
report.
Image by Tomasz Sienicki
Wood or concrete? Railroads around the world face
that decision as they replace millions of deteriorating cross ties,
also known as railway sleepers, those rectangular objects used as a
base for railroad tracks. A new report concludes that emissions of
carbon dioxide - one of the main greenhouse gases contributing to
global warming - from production of concrete sleepers are up to six
times less than emissions associated with timber sleepers. The study
is scheduled for the June 1 issue of ACS' Environmental Science &
Technology, a semi-monthly journal.
In the study, Robert Crawford points out that there
have been long-standing concerns about environmental consequences of
manufacturing railway sleepers because it involves harvesting large
amounts of timber. Reinforced concrete sleepers are an alternative
that offer greater strength, durability and long-term cost savings, he
said. Critics of using concrete sleepers have charged that their
manufacture increases greenhouse gas emissions as it involves higher
consumption of fuel when compared to production of wood sleepers.
Crawford studied the greenhouse gas emissions of
wooden and reinforced concrete sleepers based on one kilometer (0.62
miles) length of track over a 100-year life cycle. He found that
emissions from reinforced concrete sleepers can be from two to six
times lower than those from timber. "The results suggest strongly that
reinforced concrete sleepers result in lower life cycle greenhouse
emissions than timber sleepers," the report states. - JS
Sweet deception: New test distinguishes impure
honey from the real thing
Scientists have developed a test
to identify adulterated or impure honey.
Image credit: U.S. Department of
Agriculture
Here's some sweet news for honey lovers:
Researchers in France are reporting development of a simple test for
distinguishing 100 percent natural honeys from adulterated or impure
versions that they say are increasingly being foisted off on consumers.
Their study appears in ACS' Journal of Agricultural and Food Chemistry,
a bi-weekly publication.
Bernard Herbreteau and colleagues point out that
the high price of honey and its limited supply has led some beekeepers
and food processors to fraudulently make and sell impure honey doped
with inexpensive sweeteners, such as corn syrup. These knock-offs are
almost physically and chemically indistinguishable from the real thing.
Scientists need a better way to identify adulterated honey, the
researchers say.
Herbreteau and colleagues describe a new, highly
sensitive test that uses a special type of chromatography to separate
and identify complex sugars (polysaccharides) on their characteristic
chemical fingerprints. To test their method, the scientists obtained
three different varieties of pure honey from a single beekeeper and
then prepared adulterated samples of the honeys by adding 1 percent
corn syrup. They showed that the new technique accurately
distinguished the impure honeys from the pure versions based on
differences in their sugar content. - MTS
New "smart" polymer reduces radioactive waste at
nuclear power plants
Researchers have created a
"smart" polymer that could decrease radioactive waste at nuclear
power plants.
[Image credit: Wikimedia Commons]
Scientists in Germany and India are reporting
development of a new polymer that reduces the amount of radioactive
waste produced during routine operation of nuclear reactors. Their
study, which details a first-of-its-kind discovery, has been published
in the ACS' Industrial & Engineering Chemistry Research, a bi-weekly
journal.
B?je Sellergren and colleagues note that
structural materials such as carbon steel in power plants' water
cooling systems form deposits of metal oxides when they interact with
coolants. In nuclear power plants, these oxides trap radioactive ions,
leading to buildups of radioactivity that require costly cleanups of
reactor surfaces. Cobalt, present in some alloys used in the reactors'
water systems, is a major contributor toward this problem because of
its long half-life.
In the study, the researchers created an adsorbent
material that - unlike conventional ion-exchange resins that are
frequently used in reactors - is selective for cobalt but has the
unique ability of disregarding iron-based ions. The polymer's high
selectivity increases its appeal, the researchers add, for use in
decontamination processes in reactors that utilize a variety of
structural materials. - JS
New EU regulations force cosmetics firms to
abandon safety tests in animals
New European Union (EU) regulations restricting use
of animals to test the safety of shampoo, nail polish, and other
personal care products are forcing cosmetic makers to seek alternative
ways to test these products, according to an article scheduled for the
May 11 issue of Chemical & Engineering News, ACS' weekly newsmagazine.
C&EN senior correspondent Marc Reisch explains in
the cover story that an EU regulation now restricts use of animal
testing, and will totally ban it effective in 2013. "Its influence is
far reaching because it will affect substances imported into the EU
and because EU regulations are often adopted in other countries," the
article notes.
As a result, cosmetic makers are evaluating safety
with so-called in vitro or "test tube" testing, simulations of
cosmetic effects with computers, and safety information in existing
databases. Some manufacturers express concern because EU officials
have not yet validated all of the new testing methods and worry that
the regulations could stifle development of innovative cosmetic
ingredients.
Gene - altering compounds released from forest
fires
Scientists are reporting that
gene-altering substances called alkaloids are released in forest
fires.
Image by Wikipedia Commons
Scientists in Washington State are reporting the
first discovery of potent mutagenic substances in smoke from forest
fires that often sweep through huge stands of Ponderosa pine in the
western United States and Canada. Their discovery of these mutagens -
substances that can damage the genetic material DNA - is scheduled for
the June 1 edition of ACS' Environmental Science & Technology, a
semi-monthly journal.
In the study, Julia Laskin and colleagues note that
forest fires long have been recognized as major sources of organic
compounds containing nitrogen. But their research is the first to show
that the nitrogen compounds exist as alkaloids, which are naturally
occurring mutagens that are produced by trees and other plants.
Ponderosa pine trees, the researchers note, often
grow in droughty areas and in forests subject to large-scale outbreaks
of fires, and have high levels of alkaloids in their needles. Fires
help to transfer alkaloids from needles into tiny particles that can
be then transported through the air. Noting that the alkaloids can be
transported long distances, the scientists say that fires involving
Ponderosa pines could have adverse human health effects. - JS
New computer program promises to be "Rosetta
Stone" for chemical names
A new computer program that
translates complex chemical names into various languages could
help speed drug development worldwide, scientists report.
Image by The American Chemical
Society
In an advance that will help speed global
development of new drugs and patenting of new commercial and
industrial products, a scientist in New Mexico is reporting
development of the first computer program that can quickly and
accurately translate complex chemical names from one language into
another. The study is in the current edition of ACS' Journal of
Chemical Information and Modeling, a bi-monthly publication.
Roger Sayle notes that a universal system for
naming chemicals does exist. However, translating chemical names from
one language into another can be a complex task due to differences in
spacing, capitalization, spelling, and other factors. Proper
translation from English to Chinese, for example, often requires the
use of specially trained chemists who are fluent in both languages.
Although scientists have tried for decades to create computer software
for quickly translating chemical names into other languages, there's
been limited progress in this area until now, Sayle notes.
Sayle reports development of a new version of a
powerful computer program called Lexichem that can perform those
translations. The study describes how that program translated a group
of more than 250,000 chemical names from English to seven other
languages (and back) with a 98 percent accuracy rate. - MTS
Toward giving artificial cells the ability for
sustained movement
Scientists in Japan are reporting an advance toward
giving artificial cells another hallmark of life - the ability to tap
an energy source and use it to undergo sustained movement. Their study,
published in the Journal of the American Chemical Society, describes
the first "self-propelled" oil droplets (used as a model for research
on artificial cells) that can run on a chemical "fuel."
Tadashi Sugawara and Taro Toyota and other
colleagues note in the new study that scientists have tried for years
to find a method for producing oil droplets that undergo controlled
movement from one point to another. Despite identifying several
promising approaches, researchers have never found an ideal method
that they can easily control.
The new study describes development of oil droplets
equipped with chemical "engines" - highly reactive catalysts - that
provide self-propelled motion in the presence of a chemical "fuel."
This fuel consists of special substances that react in the presence of
the catalyst. When the researchers placed droplets in water containing
the fuel, the droplets moved in a controlled fashion toward areas with
the highest concentration of fuel. The researchers also say that when
another droplet comes close the newcomer it is trapped by the trail of
wastes released by the first droplet. Then the two move together in a
"communicative" manner. When the fuel was exhausted, the droplets
slowed down and stopped. The study serves as a long-awaited blueprint
for designing similar locomotion systems in artificial cells, the
scientists say. - MTS
Mercury levels in Arctic seals may be linked to
global warming
Researchers are reporting that high mercury
levels in Arctic seals appear to be linked to vanishing sea ice
caused by global warming.
Image credit: National Oceanic and Atmospheric
Administration.
Researchers in Canada are reporting for the first
time that high mercury levels in certain Arctic seals appear to be
linked to vanishing sea ice caused by global warming. Their study, a
new insight into the impact of climate change on Arctic marine life,
is scheduled for the May 1 issue of ACS' Environmental Science &
Technology, a semi-monthly journal.
Gary Stern and colleagues note in the new study
that Canadian Arctic ringed seals, like many Arctic marine animals,
have relatively high levels of mercury. However, researchers have
never determined how these levels are linked to sea ice extent and the
resulting composition of arctic cod and other prey containing mercury
available to ringed seals.
The scientists analyzed the mercury content in
muscle samples collected from ringed seals between 1973 and 2007. They
then compared the levels to the length of the so-called "summer
ice-free season," a warm period marked by vanishing sea ice in the
seals' habitat. They found that the seals accumulated more mercury
during both short (2 months) and long (5 months) ice-free seasons and
postulate that this is related to the seals' food supplies. Higher
seal mercury concentrations may follow relatively short ice-free
seasons due to consumption of older, more highly contaminated Arctic
cod while relatively long ice-free seasons may promote higher pelagic
productivity and thus increased survival and abundance of Arctic cod
with the overall result of more fish consumption and greater exposure
to mercury. Longer ice-free seasons resulting from a warming Arctic
may therefore result in higher mercury levels in ringed seal
populations as well as their predators (polar bears and humans). - MTS
"Stinky" drywall imported from China raises
health and safety concerns
Homeowners throughout the nation are complaining of
stinky odors, copper pipe and wire corrosion, and respiratory problems
in an ongoing crisis that officials say is linked to drywall imported
from China. An article on this topic is scheduled for the May 4 issue
of Chemical & Engineering News, ACS' weekly newsmagazine.
C&EN associate editor Bethany Halford explains in
the article that drywall - also known as wallboard, plasterboard, and
gypsum board - is composed of a gypsum, a chalk-like material. Spurred
by complaints from homeowners that their homes smell like rotten eggs,
investigators have traced the problem to drywall imported from China
starting in 2004. But officials do not know the exact chemicals that
are causing the problem and how they got into the drywall.
Researchers suspect that the odors are caused by
certain sulfur-containing substances in the drywall. Released as gases,
these substances can corrode copper pipes, wiring, and air
conditioning coils, the article notes. Although officials believe that
the gases do not pose a serious health threat, many homeowners with
the drywall have reported nosebleeds, sinus problems, and respiratory
infections. Several government agencies are now investigating the
exact health effects caused by exposure to these gases as well as the
electrical safety issues related to corrosion of copper wiring.
The author- or copyrights of the listed Internet pages
are held by the respective authors or site operators, who are also responsible
for the content of the presentations.
