(Press-News.org) Georgia, US - A team of Bioengineers in the United States have modified a strain of bacteria to increase its ability to produce ethanol. The research, published in Biotechnology and Bioengineering, reveals how adaptation and metabolic engineering can be combined for strain improvement, a positive development for the biofuel industry.
The team focused their research on Zymomonas mobilis, a bacterium noted for its bio-ethanol producing potential. However, the team believed that ethanol production could be increased through improvement of xylose fermentation.
"Zymomonas mobilis is a superb ethanol producer with productivity exceeding yeast strains by several fold," said lead author Rachel Chen from the Georgia Institute of Technology. "In this study we sought to improve ethanol production by enhancing the ability of Z. mobilis to use and ferment xylose. Fermenting xylose at high concentration could in turn increase ethanol concentration, resulting in much improved productivity."
The team found that by metabolically altering the strain, sugar fermentation time was reduced from over 110 hours to about 35 hours. This improvement in fermentation allowed the strain to ferment higher concentrations of xylose.
"This demonstrated increase in fermentation and xylose utilization enabled us to produce ethanol to a concentration of 9% (w/v), the highest ever shown for this organism in mixed sugar fermentation," said Chen.
This research also investigated the underlying mechanism for the improvement. Interestingly, by adapting a strain in a high concentration of xylose, significant alterations of metabolism occurred.
One noticeable change was reduced levels of xylitol, a byproduct of xylose fermentation which can inhibit the strain's xylose metabolism. In addition, the first step of xylose metabolism, believed to be the rate-limiting step, was accelerated 4-8 times in the adapted strain, with the net effect of channeling xylose to ethanol instead of xylitol.
"This research illustrates the power of adaptation in strain improvement," concluded Chen. "This confirms that xylitol metabolism is the key to efficient use of xylose in this bacterium, which in turn can be vital for producing ethanol. This shows that adaptation is not only useful in improving strains, but is equally useful for pinpointing key bottlenecks in metabolically engineered strains."
### END
Bioengineers develop bacterial strain to increase ethanol biofuel production
2010-12-10
ELSE PRESS RELEASES FROM THIS DATE:
Financial burden greater for college students with divorced or remarried parents
2010-12-10
College students whose parents have remained married to each other are faring better financially than their peers with divorced or remarried parents, according to new research from Rice University and the University of Wisconsin.
The study, published in the December Journal of Family Issues, found that divorced parents contributed about a third of what married parents contributed to their children's education even though the divorced parents' incomes are about half as much as their married peers'; remarried parents contributed about half of what married parents contributed, ...
Protein targeted to stop melanoma tumor growth
2010-12-10
Halting the growth of melanoma tumors by targeting the MIC-1 protein that promotes blood vessel development in tumors may lead to better treatment of this invasive and deadly cancer, according to Penn State College of Medicine researchers in The Foreman Foundation Research Laboratory.
"Preventing vessels from developing in tumors is one way to stop them from growing," said lead author Gavin Robertson, Ph.D., professor of pharmacology, pathology, dermatology and surgery. "However, the identity of the proteins secreted by tumors cells enabling the angiogenesis process to ...
Platinum and blue light combine to combat cancer
2010-12-10
When it comes to health care blue lights, are usually most useful on the top of ambulances but now new research led by the University of Warwick has found a way to use blue light to activate what could be a highly potent platinum-based cancer treatment.
Research led by the University of Warwick, along with researchers from Ninewells Hospital Dundee, and the University of Edinburgh, have found a new light-activated platinum-based compound that is up to 80 times more powerful than other platinum-based anti-cancer drugs and which can use "light activation" to kill cancer ...
Digital video recorders do not change shopping behavior
2010-12-10
Watching a television show from a digital video recorder (DVR) gives viewers a chance to skip commercials, but new research finds that owning a DVR does not influence the demand for advertised products despite its ad-skipping feature.
In fact, only a small percentage of ads were fast-forwarded by DVR users who participated in the study, and even that did not have an adverse effect on sales.
The research was conducted by Jean-Pierre Dube from the University of Chicago Booth School of Business, Bart Bronnenberg from Tilburg University in The Netherlands and Carl Mela ...
Drug combination shows promise for newly diagnosed blood cancer patients, study finds
2010-12-10
ANN ARBOR, Mich. — A new three-drug combination used to treat the blood cancer multiple myeloma may be effective as a front-line therapy for newly diagnosed patients, according to a study led by the University of Michigan Comprehensive Cancer Center.
The drug combination includes a novel proteasome inhibitor called carfilzomib, combined with lenalidomide and low-dose dexamethasone. This is the first study to look at carfilzomib as a front-line treatment of patients with myeloma, a type of cancer that arises in the plasma cells.
Initial results of the phase I study were ...
Chinese study suggests that alcohol increases angiographically significant coronary artery disease
2010-12-10
Among a large number of Chinese men presenting with chest pain or EKG changes, sequential subjects undergoing cardiac angiography were evaluated for obstructive coronary artery disease (CAD) lesions according to their reported recent alcohol intake. The study population consisted of 1,476 consecutive men 36 to 84 years of age; participants were categorized as nondrinkers, light drinkers, moderate drinkers, or heavy drinkers.
Adjusted odds ratios for angiographically proved CAD for light, moderate, and heavy drinking were 1.16 (95% confidence interval 0.68 to 1.94), ...
A 'stitch in time' could help damaged hearts
2010-12-10
WORCESTER, Mass. – A research team at Worcester Polytechnic Institute (WPI) has demonstrated the feasibility of a novel technology that a surgeon could use to deliver stem cells to targeted areas of the body to repair diseased or damaged tissue, including cardiac muscle damaged by a heart attack. The technique involves bundling biopolymer microthreads into biological sutures and seeding the sutures with stem cells. The team has shown that the adult bone-marrow-derived stem cells will multiply while attached to the threads and retain their ability to differentiate and grow ...
IU study: When to end a run
2010-12-10
Runners who continue running when they are exhausted unknowingly change their running form, which could be related to an increased risk for injury.
A study by Tracy Dierks, assistant professor of physical therapy at Indiana University, found that toward the end of a normal running session, runners generally displayed an increase in motion in their hips, knees and ankles.
"Our study showed that at the end of a normal run, when they were getting tired, their mechanics were beginning to change," Dierks said. "When you notice fatigue, you're most likely putting yourself ...
Better batteries from the bottom up
2010-12-10
Rice University researchers have moved a step closer to creating robust, three-dimensional microbatteries that would charge faster and hold other advantages over conventional lithium-ion batteries. They could power new generations of remote sensors, display screens, smart cards, flexible electronics and biomedical devices.
The batteries employ vertical arrays of nickel-tin nanowires perfectly encased in PMMA, a widely used polymer best known as Plexiglas. The Rice laboratory of Pulickel Ajayan found a way to reliably coat single nanowires with a smooth layer of a PMMA-based ...
Sesame Street program improves development for children in Indonesia
2010-12-10
Children exposed to Jalan Sesama, an Indonesian version of the children's television show Sesame Street, had improved educational skills and healthy development, according to a study by researchers at the Johns Hopkins Bloomberg School of Public Health. Over a 14-week period, the children who had the greatest exposure to Jalan Sesama improved significantly in literacy, mathematics, early cognitive skills, safety knowledge and social awareness, compared to those with no or low exposure to the program. The study is available online in advance of publication in the International ...