Bountiful Algae

Half of the protein to feed the world's population could be raised on an area not much bigger than Rhode Island. So says the Carnegie Institution, in a report on the possibility of extracting foodstuffs from algae. The protein would be produced by growing one-celled algae (closely related to the green scum that forms on stagnant ponds) in "farms" resembling chemical factories, which may some day provide mankind with almost unlimited food.

Conventional crop plants, says the report, have many shortcomings. The food they produce by the action of sunlight is formed in their leaves, which are usually inedible and must be supported and supplied by many other inedible parts. Generally only the seeds and tubers can be eaten by man. Another trouble with conventional food plants: when they are young, they cover only a little ground. A field of thriving, knee-high corn may delight a farmer, but to a chemist's eye it is shockingly inefficient. It utilizes only a small fraction of the sunlight falling on the field.

Edible Cell. The micoscopic algae used in the experiments have none of these failings. They have only one part, their single cell, and it is packed with green, foodmaking chlorophyll. It also stores the food it makes, and it reproduces by splitting in two every twelve hours or so. A culture of algae is always at the height of its growing season. The whole plant is edible, and since it grows under water, it never suffers from wind, hail or frost. It can be fed with nutrients (chiefly carbon dioxide and combined nitrogen) by the simple method of dissolving them in water.

An algal culture has its drawbacks: it cannot be grown effectively in open ponds or tanks, where it quickly runs out of carbon dioxide or falls prey to microscopic predators. The best way to handle it is to circulate it rapidly through wide, flat tubes of thin plastic. The cells utilize sunlight most efficiently when they are exposed to its full intensity for only a fraction of a second at a time. So the flow of the culture must be turbulent, bringing the cells to the surface for a short time, then carrying them down into shaded depths. The "crop," a bright green paste, is harvested by settling or centrifuging. It spoils quickly if not preserved in some way, has a vegetable taste that is a little like raw lima beans, and when dried, contains about 50% protein.

Famine into Feast? With considerable effort, the Carnegie Institution harvested about 100 Ibs. of this foodstuff, enough for testing its food value. Its report does not claim that it will be easy to grow algae on a really large scale. One possible way to overcome some of the difficulties: developing new strains of algae that will grow efficiently under factory conditions, including higher temperatures. But even without improvements, the Carnegiemen believe that their pilot plant can produce 17.5 tons of dry algae per acre per year. Soybeans, which contain less protein than algae do, average only 1,300 Ibs. per acre per year.

Scientists of two land-poor but technically skilled countries, Japan and Israel, are already looking into the process. If Israel, for instance, were to cover half of its meager area with algae farms, it could produce, theoretically, enough protein to feed the whole world.

This file is automatically generated by a robot program, so reader's discretion is required.