A number of red seaweeds, including Gelidium, are utilized
for their natural gums. The phycocolloid agar is extracted from Gelidium and
used for its gelling properties in a wide variety of products. Gelidium yields
high quality agar with high gelling strength and low sulfate content.
Agar is perhaps best known for its use in culturing bacteria and fungi.
In recent years, it has been utilized for biomedical techniques such
as gel electrophoresis. The form used for such processes is known as agarose
and is more purified than most agar. Agar is also used in food prodution
and transport: in canning foods, transporting cooked fish in gel, and
as a clarifying agent in making beer, wine and coffee. It also has been
used as a laxative. A little known use of agar is in finishing fabrics like
silk to maintain sheen. Many more uses of agar exist.
Agar industries exist in at least 22 countries. Those where Gelidium is
used in the production of agar include Japan, Korea, Taiwan, Indonesia, U.S.A.,
Mexico, Chile, Spain, France and South Africa. Though historically, Gelidium has
been used widely in the agar industry, in recent years it has been falling
out of favor because it grows more slowly and is less responsive to aquaculture
conditions than other agarophytes such as Gracilaria. At present, aquaculture
of Gelidium is only done on an experimental basis with limited success.
The Gelidium used in industrial production of agar is all harvested
from wild stocks. The harvesting is done with relatively low technological
processes including collecting from drift after storms, collection in the intertidal
at low tide, and collection in the subtidal using snorkeling and SCUBA diving
in deeper waters. In Japan, dredging techniques are also used. Some regulation
of the wild Gelidium stocks has been enacted in Japan by fisherman's
collectives that recognized the need to manage the resource. However, in the
future, as the need for agarose from Gelidium grows for specialized
biomedical processes, it will probably be important to manage wild stocks of Gelidium to
keep populations sustainable.
Finally, in countries such as Japan, China, Indonesia and Borneo, species of Gelidium are
eaten. Seaweed may be enjoyed fresh or may be pickled or dried. Gelidium is
also made into jellies which are eaten with other kinds of foods.
[ Life History | Taxonomy | Distribution | Chemistry | Uses | Sources ]
© 1999 Sharon C. Komarow. All rights reserved.