DVDs coated with a light-sensitive protein may be able to store 50 terabytes of data, according to researchers of Harvard Medical School.

A protein layer, made from tiny genetically altered microbe proteins, could allow DVDs and other external devices to store terabytes of information.

Professor V Renugopalakrishnan of the Harvard Medical School in Boston reported his findings at the International Conference on Nanoscience and Nanotechnology in Brisbane this week, according to ABC Australia,

Renugopalakrishnan says high-capacity storage devices like the new protein-based DVDs will be essential to the defence, medical and entertainment industries.

These trade in terabytes of information with the transfer of information such as satellite images, imaging scans and movies.

The new protein-based DVD is expected to have advantages over current optical storage devices (such as the Blu-ray). It will be able to store at least 20 times more than the Blue-ray and eventually even up to 50,000 gigabytes (about 50 terabytes) of information.

The star at the centre of the high-capacity DVD is a light-activated protein found in the membrane of a salt marsh microbe Halobacterium salinarum.

The protein captures and stores sunlight to convert it to chemical energy.

When light shines on bR, it is converted to a series of intermediate molecules each with a unique shape and colour before returning to its 'ground state'.

The intermediates generally only last for hours or days.

But Renugopalakrishnan and colleagues modified the DNA that produces bR protein to produce an intermediate that lasts for more than several years, which paves the way for a binary system to store data.

"The ground state could be the zero and any of the intermediates could be the one," he says.

The scientists also engineered the bR protein to make its intermediates more stable at the high temperatures generated by storing terabytes of data.

In conjunction with NEC in Japan, Renugopalakrishnan's team has produced a prototype device and estimate a USB disk will be commercialised in 12 months and a DVD in 18 to 24 months.

The work has been funded by a range of US military, government, academic institutions and commercial companies, as well as the European Union.