While workers have exhausted themselves cleaning large amounts of Sargassum horneri and Sargassum cristaefolium, two species of brown macroalgae, on the shores of northern Taiwan for the past several weeks, researchers regard these organisms as a rare bonanza for their biofuel and alternative foodstuff potentials.
A Council on Agriculture-sponsored team led by National Taiwan Ocean University Department of Foods professor Pan Tzong-liang and Chen Yan-chang, an associate professor in the aquaculture department, has nurtured various types of algae as potential biofuels or food sources for the past three years, discovering that these algae can be processed to yield not only alcohol and a source of food, but also used to absorb CO2. A yearlong test of the common green alga Ulva lactuca, for example, has shown that 12 metric tons of it can absorb 1.3 metric tons of CO2 per square meter.
Chen has set up an algae growing station near the university, and also brings back tons of Sargassum horneri each day from nearby beaches. At present, it is sitting in tubs for observation and occasional testing. Chen says that this algae grows very rapidly and prefers salt water at 26 degrees Centigrade or below. It can double in size in just ten days or so, so that it is now ubiquitous along the northern coast.
Pan says that these two species of algae are the best suited of all for the production of biofuels. In the university laboratory, Pan has managed to produce 23.6 grams of alcohol from 100 grams of algae, very close to the international record to date of 28 grams. However, from an efficiency perspective and looking at the ratio of product to raw material, it will be a while before algae can become a viable biofuel.
Pan says that at present, S.cristaefolium sells for about NT$100 per kilogram. After drying, that amount yields 100 grams of algae, equivalent to a cost of NT$100 for 23 grams of alcohol, and that still doesn’t take processing costs into account.
However, Pan says that the algae absorbs CO2 extremely well, and in the future, if the government begins assessing a “CO2 exchange tax”, algae could become a valuable commodity in Taiwan. Until then, though, the explosive growth of these two species is still a problem in the waters off the coast.
