Algae and Men
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.
Table 7.1 Total Macroalgae Harvest 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 world.
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.