Navigation Links
Nature's helpers: Using microorganisms to remove TCE from water

In 2002, Bruce Rittmann, PhD, director of the Biodesign Institutes Center for Environmental Biotechnology, received a patent for an innovative way to use nature to lend society a hand. He invented a treatment system, called the membrane biofilm reactor (MBfR), which uses naturally occurring microorganisms to remove contaminants from water.

Now Rittmann and his research team, which includes Rosa Krajmalnik-Brown and Jinwook Chung, recently published a paper in the journal Environmental Science & Technology for a new application that removes a problematic contaminant that has made local headlines.

The chlorinated solvent trichloroethene (TCE) has been found to be an increasingly problematic contaminant in groundwater. The detection of TCE recently forced the shut down of the water supply for the Greater Phoenix area municipalities of Paradise Valley and Scottsdale.

TCE has been widely used as a cleaning agent and solvent for many military, commercial, and industrial applications. Its widespread use, along with its improper handling, storage, and disposal, has resulted in frequent detection of TCE in the groundwater. TCE has the potential to cause liver damage, malfunctions in the central nervous system and it is considered a likely human carcinogen.

As with other elements, the chlorine cycle is becoming a key concern to many environmental pollution scientists, said Krajmalnik-Brown, a researcher in the Biodesign Institutes Center for Environmental Biotechnology and assistant professor in the Ira A. Fulton School of Engineerings Department of Civil and Environmental Engineering.

Transforming the chlorinated solvent to a harmless product is the best way to eliminate the harmful effects of TCE. In the case of TCE, Mother Nature is the best helper. Scientists have discovered specialized microorganisms that can replace the chlorine in the chlorinated molecules with hydrogen, a process called reductive dechlorination. While other methods are possible, they are often more costly than reductive dechlorination on a large scale, and many do not transform TCE into a harmless end product.

In the paper, the Rittmann team utilized the MBfR and a naturally occurring group of microorganisms able to remove TCE from water. Surprisingly, these microorganisms, called dehalogenerators, have an affinity for chlorinated organics and can be found all throughout nature, even in clean water supplies, the soil, and groundwater.

These bacteria respire TCE, that is, they can use TCE like we use oxygen to breathe, said Krajmalnik-Brown. They take in the TCE and they start removing the chlorines, step by step. In the ideal case, the dehalogenators remove all the chlorines, converting TCE to ethene, which is harmless.

With this knowledge in hand, the challenge for the research team was to adapt their existing MfBR system, which can remove other water contaminants, to see if it could now handle TCE. A version of the reactor that addresses perchlorate, a byproduct of rocket fuel, is already in the commercialization pipeline.

A key challenge with using these bacteria is that, if they dont dechlorinate all the way, the TCE can be converted to vinyl chloride, which is a known human carcinogen, said Krajmalnik-Brown. In other words, if you dont have complete dechlorination, you can end up having something worse than what you started with. So, it is critical to have the right mix of microorganisms for complete dechlorination.

Their approach was simple in execution. They took an existing MBfR that was handling perchlorate removal and then introduced TCE into the system.

Rittmanns MBfR works by delivering hydrogen gas to the bacteria through tiny hollow tubes submerged in water. In the right environment, the tubes become coated with a biofilm containing microorganisms. The system provides the microorganisms with hydrogen gas, which must be present for the microorganisms to change the chemical composition of a contaminant and render it harmless.

Their results indicated that the MBfR could be an incredibly versatile system, quickly adapting to now handle TCE. This was really surprising, because there wasnt any TCE at our pilot plant experiments prior to switching, said Krajmalnik-Brown. So there must have been really small amounts of the critical microorganisms in the culture. When shifted to TCE, they thrived and handled the contaminants.

By assessing the MBfR community, they found the special dehalogenating bacteria that can take the hydrogen supplied by the MBfR and reduce TCE all the way to harmless ethene. Using the latest molecular techniques, they could not only identify the bacterial population to handle TCE, but also the genes within these populations that make enzymes that detoxify TCE to ethene.

The team found one particular organism, a new type of Dehalococcoides, the bacteria known to dechlorinate TCE all the way to ethene. They were also the first group to grow these dehalogenating bacteria in a biofilm in the lab.

The bacteria are notoriously difficult to grow into a biofilm in the lab and study because they need hydrogen as an electron donor. An advantage of our system is that the MBfR can provide hydrogen through a membrane, which allows the microbial community to grow and naturally form a biofilm surrounding the membrane, said Krajmalnik-Brown.

Next, the team hopes to drive the TCE system toward commercialization. Other oxidized contaminants that the system has been effective in reducing in the laboratory setting include perchlorate, selenate (found in coal wastes and agricultural drainage), chromate (found in industrial wastes), and other chlorinated solvents.


Contact: Joe Caspermeyer
Arizona State University

Related medicine news :

1. Emmy(R)- and Golden Globe(R)-Nominated Actress Marcia Cross and Lifetime Television Deliver 20 Million Online Petition Signatures to Capitol Hill to Urge Congress to Stop Drive-Through Mastectomies
2. Using HR Performance Metrics to Optimize Operations and Profits
3. Alimera Sciences Signs Second Agreement With Emory University for Potential Treatments Using New Class of Antioxidants
4. AHF Sues L.A. Housing Dept. to Prevent Closure of AIDS Site
5. Upscale Yet Affordable Housing Sets New Standard for Seniors
6. Fox Hill Senior Condominium Development Thrives During National Housing Slump
7. Scientists using laser light to detect potential diseases via breath samples, says new study
8. Using HEPA filters may improve cardiovascular health
9. FTCR: Gov. Schwarzenegger Must Follow Through on Call to Ban Blue Cross From Using Doctors as Double-Agents to Dump Sick Patients
10. 1st EMEA application filed for product using innovative intradermal microinjection system BD Soluvia
11. Vanderbilt University Medical Center and Waters Collaborate on Tissue Imaging Research Using SYNAPT HDMS
Post Your Comments:
Related Image:
Nature's helpers: Using microorganisms to remove TCE from water
(Date:6/26/2016)... ... June 26, 2016 , ... PawPaws brand pet supplements owned by ... to enhance the health of felines. The formula is all-natural and is made from ... the PawPaws Cat Kidney Support Supplement Soft Chews are Astragalus Root Extract ...
(Date:6/26/2016)... ... June 26, 2016 , ... Many women are ... with endometriosis. These women need a treatment plan to not only alleviate symptoms ... can help for preservation of fertility and ultimately achieving a pregnancy. The specialists ...
(Date:6/25/2016)... ... 25, 2016 , ... Austin residents seeking Mohs surgery services, can now turn ... to Dr. Russell Peckham for medical and surgical dermatology. , Dr. Dorsey brings specialization ... selective fellowship in Mohs Micrographic Surgery completed by Dr. Dorsey was under the direction ...
(Date:6/25/2016)... , ... June 25, 2016 , ... "With 30 hand-drawn ... specific project," said Christina Austin - CEO of Pixel Film Studios. , ProHand ... all within Final Cut Pro X . Simply select a ProHand generator and ...
(Date:6/25/2016)... ... June 25, 2016 , ... As a lifelong Southern Californian, ... and his M.D from the David Geffen School of Medicine at UCLA. He trained ... Angeles to complete his fellowship in hematology/oncology at the UCLA-Olive View-Cedars Sinai program where ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... -- Research and Markets has announced the addition ... - Forecast to 2022" report to their offering. ... to date financial data derived from varied research sources to ... potential impact on the market during the next five years, ... of sub markets, regional and country level analysis. The report ...
(Date:6/23/2016)... , June 23, 2016 Bracket , ... launch its next generation clinical outcomes platform, Bracket eCOA (SM) ... held on June 26 – 30, 2016 in ... first electronic Clinical Outcome Assessment product of its kind to ... #715. Bracket eCOA 6.0 is a flexible platform ...
(Date:6/23/2016)... and BOGOTA, Colombia , June 23, 2016  Astellas today announced the establishment of Astellas ... Brasil as the company,s second affiliate in Latin America . ... ... of Astellas Farma Colombia ... ...
Breaking Medicine Technology: