Use of tubular photobioreactors in biomass production of Spirulina

The application of closed photobioreactors of different designs to the outdoor mass culture of oxygenic photosynthetic bacteria (Cyanobacteria) represents a real opportunity to increase the mean yield of biomass in temperate climatic conditions, which do not allow year-around production in open ponds. Results of Spirulina outdoor mass culture in closed system (pulse flow culture in tubular reactors) over the past five years showed that under the climatic conditions of Central Italy, the annual yield had almost doubled, as compared to the production in open ponds. The chemical composition of the biomass obtained from tubular photobioreactors and the merits and drawbacks of the same in the conversion of solar energy in comparison with open ponds are discussed. It is concluded that with an appropriate length of the photobioreactor and using a thermotolerant strain of Spirulina, the cooling cost is drastically reduced.