Quick Dips

Taking the Heat

A seaweed that grows only in New Zealand has been found to contain an agar extract that could sell for well over $1,000 a kilo.

The new agar is chemically different from any previously encountered. Like other agars it forms a strong gel in water, but is unusual in that the melting point of the gel is the highest known -- above 100^oC, the boiling point of water. Conventional agar melts at 90^oC or less.

The agar, derived from a red seaweed species called curdiea, was discovered by Richard Furneaux of the then DSIR Chemistry and Ian Miller, now the technical director of a Lower Hutt company, Carina Chemical Laboratories.

Furneaux says the agar compound has potential high-tech uses in scientific laboratories, including DNA processing.

Many scientific advances in biochemistry and biotechnology have de-pended on a related agar derivative called agarose. The availability of a heat-resistant agarose equivalent would allow the design of new approaches to DNA separation. The DNA double helix, which unwinds into double strands at 93^oC, could then be separated within the gel.

Furneaux says the seaweed was collected and identified by National Museum botanists Wendy Nelson and Nancy Adams from coastal waters off Northland.

Surveys of the seaweed's distribution and viability as a resource are now being undertaken by Nelson. A study of its occurrence as drift on beaches north of Kaitaia is under way, while University of Auckland scuba divers are to survey curdiea's underwater habitat.

Initial results indicate the seaweed is not as rare as first thought. Sufficient material is now available for extraction and upgrading work on the new agar.

This is being conducted in collaboration with Carina Chemical Laboratories, with the idea of producing the agar on a commercial basis.