FROM OPEN PONDS TO VERTICAL ALVEOLAR PANELS - THE ITALIAN EXPERIENCE IN THE DEVELOPMENT OF REACTORS FOR THE MASS CULTIVATION OF PHOTOTROPHIC MICROORGANISMS

The need to develop new concepts in reactor design and the growing interest in Spirulina prompted our group to abandon open ponds in the seventies and to focus interest mainly on closed systems. Two substantially different closed photobioreactors have been developed and are at present under investigation in our Research Centre: the tubular photobioreactor (made of rigid or collapsible tubes) and the recently devised vertical alveolar panel (VAP) made of 1.6-cm-thick Plexiglas alveolar sheets. The technical characteristics of the two systems are described and discussed in relation to the main factors which regulate the growth of oxygenic photosynthetic microorganisms in closed reactors.