Researchers have designed a new technology that could make it impossible for genetically modified organisms to escape into natural environments.

A team at Yale University in New Haven, Conn., has designed genetically modified E. coli bacteria that need a nutrient that doesn't exist in nature.

Yale University researcher Farren Isaacs says the genetically modified bacteria will only grow in the presence of a 'special sauce' available only in the lab. (Courtesy Farren Isaacs/Yale University)

"We can grow them in our special sauce and they'll grow, but when you try to grow them in regular media or nutrients, they die," said researcher Farren Isaacs, a Yale University researcher who co-authored the study published this week in Nature.

Genetically modified microbes are already used to manufacture many pharmaceuticals through a process called bio-fermentation. Trillions of microbes sit in huge vats, pumping out compounds ranging from insulin to human growth hormone.

Other products produced this way, including ultra-strong fibres, plastics, food products and electronic circuitry, are in the marketplace.

Concerns about GMOs

Some groups such as Greenpeace have expressed concern about the potential for such organisms to escape into the wild, as has happened with human-introduced genes from genetically modified crops.

Janet Cotter, a senior scientist with Greenpeace's science unit, said genetically modified organisms that get out into the environment are typically hard to control.

"And there is no recall, particularly with any microbes," said Cotter, who has a PhD in soil science.

The new technology aims to ease some of those concerns. The modified E. Coli bacteria require a synthetic amino acid, not found in nature, in order to activate genes necessary for growth. Amino acids are the building blocks of proteins.

In a separate study published in the same issue of Nature, George Church of Harvard University and his team designed an organism that relied on a synthetic amino acid for survival.

In an interview and at a news conference, Isaacs and Church said they believed it would be possible, although challenging, to extend their technique to genetically modified crops. That could ease concerns about spreading outside their designated fields.

Experts not connected with the work told The Associated Press they were impressed. The papers "point the way towards putting (genetically modified organisms) on a very tight leash, one that is meant to be unbreakable," Richard Lenski of Michigan State University, said in an email.

Karmella Haynes, an assistant professor of biomedical engineering and synthetic biology at Arizona State University, called the bacteria work "a significant advance." She said it would be difficult to make it work with the more complex genetic machinery of crop plants.

Rina Singh, senior director for policy of the Biotechnology Industry Organization, said the work is "extremely useful ... This is some really good stuff."

While scientists have previously used "suicide genes" to control microbes, the new approach might be easier, she said.