Phthalic symbol: Important symbol of pollution is broken down by microbes

Jun 19, 2009

Immobilized microbes can break down potentially harmful phthalates, according to researchers in China, writing in the International Journal of Environment and Pollution. The microbes might be used to treat industrial waste water and so prevent these materials from entering the environment.

Phthalic Acid Esters (PAEs), commonly known as phthalates, are widely used as additives in polymer manufacture as plasticizers. They do not readily degrade in the environment and so have become widely distributed in natural water, wastewater, soils, and sediment.

Concerns about their suspected ability to cause and cancer have led to their listing as priority pollutants by the US , the European Union, the China National Environmental Monitoring Centre, and other regulatory authorities.

Weizhong Wu of the College of Environmental Sciences and Engineering, at Peking University, in Beijing, and Xianlin Meng of Harbin Institute of Technology, in Nangang District, have identified and isolated a microbe that can digest one of the most common PAEs, d-n-butyl phthalate. This compound is widely used and is one of the most frequently found in diverse environmental samples including groundwater, river water, drinking water, open ocean water, soil humates, lake sediments and marine sediments, the researchers say.

They have now used acclimation and enrichment techniques to ferment adequate quantities of the active microbe, which was obtained from the activated sludge from a wastewater treatment plant. It was enriched and acclimated by incubating activated sludge. This involves cultivating the in a solution containing phthalate as the only source of carbon for the microbes. Successive divisions of microbial cells quickly leads to the evolution of a strain that can quickly metabolize the phthalate and convert it into the raw materials for microbial growth and reproduction.

The researchers then tested this phthalate-digesting microbe by immobilizing cells on a new type of ceramic honeycomb support. They then measured the before and after concentration of phthalate in a simulated wastewater sample. Initial concentration was 100 milligrams per liter which fell to less than 1.0 milligram per liter within two days of treatment with the microbial honeycomb.

The team points out that the rate of degradation was two and a half times faster with immobilized microbes than with microbes floating free in the sample.

More information: "Biodegradation of plasticiser di-n-butyl phthalate by immobilised microbial cells" in Int. J. Environment and Pollution, 2009, 38, 203-211

Source: Inderscience Publishers (news : web)

Explore further: Cicada study discovers two genomes that function as one

add to favorites email to friend print save as pdf

Related Stories

The microbial hydrocarbon diet

Jun 11, 2009

Bioremediation of industrial sites and petrochemical spillages often involves finding microbes that can gorge themselves on the toxic chemicals. This leaves behind a non-toxic residue or mineralized material. Writing in the ...

Bacteria That Degrade PCBs Identified

Mar 28, 2007

Researchers have identified a group of bacteria that can detoxify a common type of polychlorinated biphenyls (PCBs), which have contaminated more than 250 U.S. sites, including river and lake sediments.

Recommended for you

New tool aids stem cell engineering for medical research

16 hours ago

A Mayo Clinic researcher and his collaborators have developed an online analytic tool that will speed up and enhance the process of re-engineering cells for biomedical investigation. CellNet is a free-use Internet platform ...

New type of cell movement discovered

16 hours ago

For decades, researchers have used petri dishes to study cell movement. These classic tissue culture tools, however, only permit two-dimensional movement, very different from the three-dimensional movements ...

How the zebrafish gets its stripes

16 hours ago

The zebrafish, a small fresh water fish, owes its name to a striking pattern of blue stripes alternating with golden stripes. Three major pigment cell types, black cells, reflective silvery cells, and yellow ...

User comments : 0