Fire-retardent DNA produced by genetically engineered bacteria

Leicester University students are aiming to make polystyrene more fire resistant using genetically modified bacteria.

The team, which is to enter this year’s International Genetically Engineered Machine competition (iGEM), hopes to make use of DNA’s recently discovered application as a flame retardant to make expanded polystyrene (EPS) less flammable.

In order to produce large amounts of DNA at low costs, the students hope to genetically engineer bacteria to produce much more DNA in their cells than usual. The DNA-rich bacteria could then be added to the polystyrene to make it less susceptible to burning.

Expanded PolyStyrene (EPS) – which is frequently used for insulation in buildings – is highly flammable and Hexabromocyclododecane (HBCD) is often added as a flame retardant in construction applications.

In a statement the university pointed out that the European Union organisation REACH has listed HBCD as a ‘persistent bio-cumulative toxin’, meaning that it can accumulate in the environment and alter biological processes, such as hormone levels in fish.

REACH is phasing out HBCD by 2015, so developing an alternative flame retardant would be beneficial for the environment and the EPS industry.

As well as reducing polystyrene flammability, the team hopes to develop a way of recycling polystyrene waste for use in 3D printing, using DNA technology. They also plan to continue developing genetically modified bacteria to degrade polystyrene waste more effectively.

Team instructor, Dr Richard Badge, a lecturer in Bioinformatics in the University’s Department of Genetics, said, ‘Polystyrene is very flammable, but one of its biggest uses is in insulating building. So, while expanded polystyrene is a fantastic insulator, it needs to be made less flammable.’

‘HBCD is the main chemical that has been used to make polystyrene fire retardant, but the European organisation REACH is phasing it out, so industry is going to be really interested in developing new fire retardants.’

‘Bacteria are not particularly DNA rich, so we want to engineer the bacteria to contain more DNA. To do this, we are going to use bacteriophages – a virus which infects and replicates inside bacteria. The idea is to engineer bacteria that will produce lots of DNA once we give them the right signal.’

UK-based firm Jablite, who manufacture fire-retardant polystyrene for the construction industry, and sister company Styropack specialising in polystyrene packaging for food and medicine, are supporting the team’s project with materials and invaluable technical expertise.