Students clone bacterial genes for degradation and recycling of waste chemicals

Posted by er134 at Nov 20, 2013 09:40 AM |
University of Leicester Biological Sciences students have cloned bacterial genes involved in breaking down toluene, an environmental pollutant

Issued by University of Leicester Press Office on 20 November 2013

Leicester students have isolated three of the bacterial genes that can degrade a petro-chemical, which can pollute air, water and soil when it enters the environment.

University of Leicester Biological Sciences undergraduates cloned the DNA sequences responsible for degrading a chemical called toluene.

The cloning of these sequences could help scientists stop other oil-based chemicals from polluting the environment.

Toluene (methylbenzene) is used frequently in the chemical and pharmaceutical industries as well as in the manufacture of rubber, paints, varnishes and lacquers.

When it is released, it quickly breaks down into benzaldehyde and cresol, which are both harmful to humans.

When toluene enters the soil, it may contaminate ground water, and has been shown to cause damage to the leaves of plants, as well as having moderate toxicity to aquatic life.

Scientists had previously identified genes in soil-living bacteria (Pseudomonas putida) which enable the organism to degrade toluene, as a food source.

However, the Leicester students have now isolated the genes so they can modify them to degrade other oil-based chemicals. One of the students’ targets is polystyrene, a plastic chemically related to toluene that is currently difficult to recycle, as it is hard to break down.

This involved inserting the Pseudomonas genes into specific pieces of DNA called Biobricks, within the cells of the laboratory bacteriumEscherichia coli (E. coli).

E. coli is the microbiologists’ "test bed" - with a well-understood genome, and many techniques available for the modification of its genes.

The students carried out the research as part of the University of Leicester's 2013 entry to the iGEM (international Genetically Engineered Machine) research competition, which challenges students to synthesise novel organisms using a set of standard DNA parts.

The Leicester Biobricks have been accepted into the International Genetically Engineered Machine (iGEM) Foundations Registry of Standard Biological Parts – a repository of thousands of DNA sequences.

This means scientists and students all over the world can use the genes to potentially recycle valuable oil-based chemicals, and prevent them polluting the environment.

Ultimately, the Leicester team have advanced the goal of more easily recycling polystyrene - for which they have received financial support from the British Plastics Federation and Jablite / Styropack, a major UK polystyrene manufacturer.

The team presented the results of their summer research project in mid-October at the iGEM Competition European Jamboree, in Lyon France.

This year, the student team didn't advance to the World Championship Jamboree, held earlier this month in Boston, USA, but have high hopes for 2014, and beyond.

The students were led by Dr Richard Badge, a Lecturer in Bioinformatics in the University's Department of Genetics.

Dr Richard Badge said: “The students worked really hard over the summer to isolate the bacterial genes, gained some really valuable laboratory experience, and were rewarded by a fantastic Jamboree in France.

“It was great to see what students from all over Europe had done in their projects, and most inspiring for the future."

“European teams have a great track record in iGEM - this year 5 out of the 6 Boston finalists were EU-based so there is everything to play for.”

Brett Vahkal, 20, an undergraduate Medical Biochemistry student, said: ''The idea behind iGEM is to get students thinking about synthetic biology and how it can be used to create solutions to many of the problems the world is facing today.

“For a student, it is a great opportunity to gain invaluable lab experience over the summer and be part of a research team composed entirely of students - not to mention the international Jamboree, which was an exciting experience in itself."


Notes to editors:

For more information, please contact:

Dr Richard Badge, Lecturer in Bioinformatics in the University's Department of Genetics, at:

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