Microalgae and macroalgae have been utilized by man for hundreds of years as food, fodder,
remedies, and fertilizers. Ancient records show that people collected macroalgae for food as
long as 500 B.C. in China and one thousand of years later in Europe. Microalgae such as Arthrospira
have a history of human consumption in Mexico and Africa. In the 14th century the Aztecs
harvested Arthrospira from Lake Texcoco and used to make a sort of dry cake called tecuitlatl,
and very likely the use of this cyanobacterium as food in Chad dates back to the same period, or
even earlier, to the Kanem Empire (9th century A.D.).
People migrated from countries such as China, Japan, and Korea, but also from Indonesia and
Malaysia, where algae have always been used as food, have brought this custom with them, so that
today there are many more countries all over the world where the consumption of algae is not
unusual, Europe as well.
On the east and west coasts of the U.S. and Canada, around Maine, New Brunswick, Nova
Scotia and British Columbia, some companies have begun cultivating macroalgae onshore, in
tanks, specifically for human consumption, and their markets are growing, both in those two
countries and with exports to Japan. Ireland and Northern Ireland are showing a renewed interest
in macroalgae that were once a traditional part of the diet. In addition to direct consumption, agars
and carrageenans extracted from red macroalgae and alginates from brown macroalgae and microalgae
have been included in a remarkable array of prepared food products, serving mostly to modify
viscosity or texture. Global utilization of macroalgae is on increase, and in terms of harvested
biomass per year, macroalgae are among the most important cultivated marine organisms.
Currently, there are 42 countries in the world with reports of commercial macroalgae activity.
China holds first rank in macroalgae production, with Laminaria sp. accounting for most of its
production, followed by North Korea, South Korea, Japan, Philippines, Chile, Norway, Indonesia,
the U.S. and India. These top ten countries contribute about 95% of the world’s commercial macroalgae
volume. About 90% macroalgae production comes from culture based practices. The most
cultivated macroalgae is the kelp Laminaria japonica, which alone accounts for over 60% of the
total cultured macroalgae production while Porphyra, Kappaphycus, Undaria, Eucheuma, and
Gracilaria make up most of the rest to a total of 99%. The most valuable crop is the red alga
Nori (Porphyra species, mainly Porphyra yezzoensis), used as food in Japan, China, and Pacific.
According to FAO, between 1981 and 2002, world’s total harvest of macroalgae increased from
3 million tons to nearly 13 million tons (wet weight). The macroalgae that are most exploited
for culture are the brown algae with 6 million tons followed by the red algae with 3 million tons
and a small amount of green algae with less than 100,000 tons. East and Southeast Asian countries
contribute almost 99% cultured production, with about 75% of the production (9 million tons)
supplied by China.
Most output is used domestically for food, but there is a growing international trade. The Porphyra
cultivation in Japan is the biggest macroalgae industry, with a turnover of more than 2 billion
U.S. dollars per annum. Total EU imports of macroalgae in 2002 amounted to 70,000 metric tons
with the Philippines, Chile, and Indonesia as the biggest suppliers. Significant quantities of
Eucheuma are exported by the Philippines, Tanzania, and Indonesia to the U.S., Denmark, and
Japan. The Philippines account for nearly 80% of the world’s total Eucheuma cottonii production
of 1,300,000 tons, roughly 35% of which is traded in dried form. They supply 14% of the world’s
total raw macroalgae production and hold first rank as producers of semirefined carrageenan,
contributing close to 60% of the world market. Table 7.1 shows the FAO data relative to the total
macroalgae harvest for the period 2000–2002 in all fishing areas of the world.
Large-scale commercial production of microalgae biomass is limited to Dunaliella, Haematococcus,
Arthrospira, and Chlorella, which are cultivated in open ponds at farms located around the
These algae are a source for viable and inexpensive carotenoids, pigments, proteins, and vitamins
that can be used for the production of nutraceuticals, pharmaceuticals, animal feed additives,
and cosmetics. Examples of large-scale commercial production are the large lagoons used in
Australia for Dunaliella salina cultivation aimed at β-carotene production, the ponds that Cyanotech
Enterprise own in Australia, and Earthrise farms in California for Haematococcus cultivation
aimed at astaxanthin production.
Cyanotech Enterprise claimed that in the 2004 their net sales were about $12 billion, with a net
income only in the fourth quarter of $400,000.