Outdoor algal mass cultures—I. Applications

Abstract

Algal mass culturing research has been carried out in many parts of the world for past 30 yr. Whereas early efforts were directed towards single-celled protein production for human consumption, many new applications have evolved including wastewater treatment, water renovation, nutrient recycling, production of chemicals, aquaculture and bioconversion of solar energy. Photosynthetic yields over 30g dry wt m −2day −1 have been attained on occasion in many locations for short periods and yields between 15 and 25 g dry wt m −2 day −1 for longer periods are now common. It appears that bioconversion of solar energy with algal cultures is not attractive because of the tremendous quantities of land, water and nutrients required. Similarly, single-celled protein from microalgae is beset with numerous problems associated with nutritional quality, toxicology and economics. The main attractiveness of algal mass cultures is that they have great versatility to be integrated into multi-use systems for simultaneously solving several environmental problems. Their use probably will be limited to small specific applications and not on the massive scale projected in the past.