New bacteria strain could help produce tastier, healthier bread

March 22, 2010 By Leave a Comment

Washington, March 22 (ANI): American researchers have discovered a new bacteria strain that can help make ”super sourdough” bread.

Maija Tenkanen, and her team discovered and used of a new strain of bacteria that convert the sugars in bread dough into produce dextrans (sugar molecules linked together into long chains that enhance the texture and taste of the sourdough and help keep the bread fresh). These bacteria are available commercially, but produce large amounts of lactic acid along with dextrans.

Tenkanen said: “The advantage of this new strain of bacteria is that while it produces 10 times more dextran than products on the market now, it doesn”t produce large amounts of acid.

“Because of this feature, and because the added amount of natural dextran could actually improve the flavor, this could be used in place of additives for a broad variety of breads.”

She pointed out that the new dextrans may act as so-called “prebiotics,” non-digestible food ingredients that stimulate the growth or activity of bacteria in the digestive system which are beneficial to health.

Tenkanen explained that in the past bread-making involved a long fermentation process using bacteria and/or yeasts that gave bread a pleasant aroma and taste. But the automated bread-making processes adopted by companies are not compatible with the long fermentation processes, something requiring addition of food additives.

She said: “Now, with consumers preferring healthier, additive-free foods we believe our bacteria may lead to a variety of more healthful breads.”

The bacteria could be marketed to home and commercial bakers as a sourdough starter, or enhancer for other types of bread.

The study was presented at the American Chemical Society”s 239th National Meeting in San Francisco. (ANI)

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Producing better wine by taking the stress off yeast

September 10, 2009 By Leave a Comment

Washington, Sept 9 (ANI): Times can be stressful for yeast when grape juice is being turned into wine. Now, a researcher from the University of Valencia, Spain has identified the genes in yeast that enable it to respond to stress.

What’s more, Dr Agustin Aranda is investigating ways to improve yeast performance by modifying its stress response mechanism.

Speaking at the Society for General Microbiology meeting at Heriot-Watt University, Edinburgh, Aranda described the stresses that wine yeasts undergo in the fermentation process. Industrial wine making involves adding dried yeast starter cultures to the juice; both the drying and reactivating processes cause stress damage to the yeast cells. As the juice is fermented into wine the rising ethanol (alcohol) levels also damage the yeast cells and oxidation causes further damage.

By manipulating the genes that control the stress response of the yeast, the researchers found that they could improve its performance in industrial fermentation processes. hey found that a family of enzymes called sirtuins had an important role in controlling wine yeast lifespan.

“Our research aimed to improve winemaking techniques but our findings on oxidative stress and ageing in yeast could be potentially useful in understanding the positive roles of antioxidants present in grapes and grape juice,” said Aranda. (ANI)

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Malaria treatment developed using synthetic biology, fermentation

March 1, 2009 By Leave a Comment

Washington, Feb 28 (ANI): Achieving a milestone in the fight against malaria, scientists at Amyris Biotechnologies have produced 25 g/L of amorphadiene, a precursor of the antimalarial agent artemisinin, by using synthetic biology and E. coli fermentations.

It was in 2003 that the production of amorphadiene in E. coli was first described, but the amount produced was low (50 mg/L). The level was increased to 0.5g/L in 2006, but still 50-fold lower than target production levels.

In the new study, researchers have described the interplay of industrial fermentation processes and synthetic biology that achieve the required 50-fold increase in production levels.

This milestone acts as proof of concept that microbes for conversion to artemisinin can produce commercially relevant concentrations of artemisinin precursors.

The World Health Organization considers artemisinin-based combination therapies (ACTs) to be first-line treatment for malaria.

But, as the supplies of plant-derived artemisinin are subject to the seasonality and volatility common to many plant-based commodities, it leads to fluctuations in the price of artemisinin.

Commercial scale production of semi-synthetic artemisinin would have the potential to stabilize supply and supplement existing plant-derived materials to create a consistent, high-quality and affordable new source of artemisinin to help meet the projected world-wide demand for ACTs.

Originally, the microbial production of Artemisinin precursors was demonstrated in the lab of Professor Jay Keasling at the University of California, Berkeley.

Then Keasling continued the research and founded Amyris to bring the technology to the developing world.

Dr. Jack Newman, a former Post-doc in the Keasling lab and co-founder of Amyris, praised the collaboration effort and the potential of the technology.

“The enormous amount of work involved on the road from idea through execution is mind-boggling. I’m grateful to the dedicated team of researchers, philanthropists and visionaries that made this happen. They have demonstrated the potential of this technology to make a difference in the world,” he said

The article, “High-level production of amorpha-4,11-diene, a precursor of the antimalarial agent artemisinin, in Escherichia coli” appears in PLoS ONE, an open-access journal from the Public Library of Science. (ANI)

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Butanol made from plants could displace petroleum-derived version

January 11, 2009 By Leave a Comment

Washington, Jan 11 (ANI): A University of Illinois researcher has determined that butanol made from plant material could displace butanol made from petroleum, and that too just not at the fuel pump.

“Yes, you can drive your car around with 100 percent butanol, but butanol is much more valuable – about three times more valuable – as a chemical than as a liquid fuel,” said Hans Blaschek, microbiologist in the College of Agricultural, Consumer and Environmental Sciences at Illinois.

According to Blaschek, butanol has all kinds of attributes that would make it a good candidate for liquid fuel.

It burns cleaner, it has higher energy density than ethanol, but it’s more expensive currently.

“It would displace petroleum and that’s huge – clearly it could be used as a liquid fuel, but right now it’s still too expensive to use that way. Right now, it follows the price of propelene,” Blaschek said.

Blaschek has been studying microorganisms that are used in fermentation processes for over 25 years.

About 10 years ago, his lab at Illinois had a breakthrough with the development of a mutant strain of a soil bacterium called Clostridium beijerinckii that produces higher concentrations of butanol when added to a vat of plant byproduct.

“One of the beauties of Clostridium, is that unlike yeast that can only use six carbon sugars, this organism can use five or six carbon sugars, so you’re not limited. You can use distiller’s grains, biomass, pretty much anything that can be deconstructed to sugars and can be fermented,” Blaschek explained.

“Clostridium eats both and it does it naturally. You don’t have to engineer the organism like people have been doing for the last 20 years with yeast trying to get it to use five carbon sugars,” he added.

Because the mutant strain produces higher concentrations of butanol, it’s the basis for Tetravitae BioSciences, a local company that licensed the patented strain from the University of Illinois and is scaling up to use the over-productive strain on a large scale – the size of an ethanol plant. (ANI)

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