Soybeans a source of valuable chemical

December 19, 2012

The humble soybean could become an inexpensive new source of a widely used chemical for plastics, textiles, drugs, solvents and as a food additive.

Succinic acid, traditionally drawn from petroleum, is one focus of research by Rice chemists George Bennett and Ka-Yiu San. In 2004, the Department of Energy named succinic acid one of 12 "platform" chemicals that could be produced from sugars by biological means and turned into high-value materials.

Several years ago, Rice patented a process by Bennett and San for the bio-based production of succinic acid that employed genetically modified E. coli bacteria to convert glucose into succinic acid in a way that would be competitive with petroleum-based production.

The new succinate process developed by Bennett, San and Chandresh Thakker and reported recently in Bioresource Technology promises to make even better use of a cheap and plentiful feedstock, primarily the indigestible parts of the soybean.

"We are trying to find a cheaper, renewable raw material to start with so the end product will be more profitable," said Thakker, a research scientist in the Bennett lab at Rice's BioScience Research Collaborative and lead author of the study. "The challenge has been to make this biomass process cost-competitive with the petrochemical methods people have been using for many years."

Bennett feels they have done that with soybean-derived feedstock as an inexpensive source of the carbon that microorganisms digest to produce the desired chemical via fermentation. "A lot of people use plant oils for cooking - corn or soybean or canola -- instead of lard, as they did in the old days," he said. "The oils are among the main products of these seeds. Another product is protein, which is used as a high-quality food.

"What's left over is indigestible fiber and small carbohydrates," said Bennett, Rice's E. Dell Butcher Professor of Biochemistry and Cell Biology. "It's used in small amounts in certain animal feeds, but overall it's a very low-value material."

The Rice researchers are changing that with the help of E. coli bacteria engineered to process soy meal that generally gets discarded. Certain microbes naturally produce succinic acid from such feedstock, but manipulating E. coli's metabolic pathways (by eliminating pathways that produce other chemicals like ethanol, for instance) can make it far more efficient.

Expanding on their success in producing succinic acid from glucose, the new microbes are engineered to metabolize a variety of sugars found in soybean meal. The theoretical ideal is a 1:1 ratio of feedstock (the extracted sugars) to product, which they feel is achievable by industry. In the lab, under less controlled conditions, they still found the process highly efficient. "We're demonstrating a very high yield," Thakker said. "We're achieving in a flask a non-optimized formation of succinate that is close to the theoretical goal."

Bennett said his lab has been looking at soybeans for nearly three years. "We're always interested in low-cost feedstock," he said. "We were able to get a connection with a soybean group that is very interested in technologies to make better and more profitable use of their crop.

"There's a fair amount of oilseed residuals available including cottonseed carbohydrates, that's not used for any high-value product, and we're in the space of microbial engineering to enable these sorts of materials to be used in a good way," he said.
-end-
Ka-Yiu San is the E.D. Butcher Professor of Bioengineering and a professor of chemical and biomolecular engineering at Rice.

The United Soybean Board and the National Science Foundation supported the research.

Read the abstract at http://www.sciencedirect.com/science/article/pii/S096085241201663X

This news release can be found online at news.rice.edu.

Follow Rice News and Media Relations via Twitter @RiceUNews

Related Materials:

Bennett Group: http://www.bioc.rice.edu/%7Egbennett/

San Group: http://www.ruf.rice.edu/~ksan/

Images for download:

http://news.rice.edu/wp-content/uploads/2012/12/soybean-1-web.jpg

Indigestible byproducts of soybeans can be turned into valuable succinic acid through a process developed at Rice University. (Credit: Photos.com)

http://news.rice.edu/wp-content/uploads/2012/12/soybean-team-web.jpg

A team of Rice University chemists is modifying E. coli bacteria to produce valuable succinic acid from byproducts of soybeans. From left: Professor George Bennett, research scientist Chandresh Thakker and Professor Ka-Yiu San. (Credit: Rice University)

http://news.rice.edu/wp-content/uploads/2012/12/Soy-to-succinate.jpg

Byproducts of soybeans include soluble carbohydrates that can be turned to succinic acid when metabolized by E. coli bacteria engineered at Rice University. Succinic acid is used in a variety of products, including plastics, textiles, drugs, solvents and food. (Credit: Bennett Lab/Rice University)

Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,708 undergraduates and 2,374 graduate students, Rice's undergraduate student-to-faculty ratio is 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice has been ranked No. 1 for best quality of life multiple times by the Princeton Review and No. 2 for "best value" among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to http://tinyurl.com/AboutRice.

Rice University

Related Microbes Articles from Brightsurf:

A new look at deep-sea microbes
Microbes found deeper in the ocean are believed to have slow population turnover rates and low amounts of available energy.

Microbes might manage your cholesterol
Researchers discover a link between human blood cholesterol levels and a gene in the microbiome that could one day help people manage their cholesterol through diet, probiotics, or entirely new types of treatment.

Can your gut microbes tell you how old you really are?
Harvard longevity researchers in collaboration with Insilico Medicine develop the first AI-powered microbiomic aging clock

What can be learned from the microbes on a turtle's shell?
Research published in the journal Microbiology has found that a unique type of algae, usually only seen on the shells of turtles, affects the surrounding microbial communities.

Life, liberty -- and access to microbes?
Poverty increases the risk for numerous diseases by limiting people's access to healthy food, environments and stress-free conditions.

Rye is healthy, thanks to an interplay of microbes
Eating rye comes with a variety of health benefits. A new study from the University of Eastern Finland now shows that both lactic acid bacteria and gut bacteria contribute to the health benefits of rye.

Gut microbes may affect the course of ALS
Researchers isolated a molecule that may be under-produced in the guts of patients.

Gut microbes associated with temperament traits in children
Scientists in the FinnBrain research project of the University of Turku discovered that the gut microbes of a 2.5-month-old infant are associated with the temperament traits manifested at six months of age.

Gut microbes eat our medication
Researchers have discovered one of the first concrete examples of how the microbiome can interfere with a drug's intended path through the body.

Microbes can grow on nitric oxide
Nitric oxide (NO) is a central molecule of the global nitrogen cycle.

Read More: Microbes News and Microbes Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.