High-Density Algal Photobioreactors

초록

Algal biotechnology is drawing increasing interest due to its potential as a source of valuable pharmaceuticals, pigments, carbohydrates, and other fine chemicals. Currently, its application is being extended to the areas of wastewater treatment and agriculture. However, lack of suitable photobioreactors (PBRs) makes the cost of algally-derived compounds higher than those derived by chemical synthesis and thus has prevented widespread use of algal cultures. The culture of algae prior to the late 1940s was apparently restricted to laboratory scale operations. Experiments on outdoor algal mass production began in the late 1940s with nearly concurrent development of experimental culture facilities in Germany and the United States. For the next two decades, outdoor mass culture of algae was undoubtedly the hottest topic in the algal biotechnology area. Recent developments of high-density PBRs enable the production of valuable biologically active compounds by algal mass cultures. Futhermore, these PBRs can be applied in various algal biotechnology areas, such as production of wastewater treatments and carbon dioxide fixation. Various photobioreactors will be analyzed and compared for their advantages and disadvantages. We have calculated theoretical values of gas mass transfer requirements, light intensity requirements and distribution, and mass balance. The new techniques, such as fed-batch, flashing light and lumostatic operation, that can improve productivity of these PBRs will be introduced.