A Modular Flat Panel Photobioreactor (MFPP) for indoor mass cultivation of Nannochloropsis sp. under artificial illumination

Nannochloropsis sp. was grown in a Modular Flat Panel Photobioreactor (MFPP) consisting of six alveolar panels each with 20.5 L culture volume and 3.4 m2 illuminated surface area. The panels formed a closely-packed unit with illumination provided by banks of fluorescent tubes placed between the panels. The whole unit was contained in a thermoregulated cabinet. Continuous illumination of one side of the panels with 115 mol photon m-2 s-1 attained a mean volumetric productivity of 0.61 g (d. wt) L-1 24 h-1, increasing to 0.97 g (d. wt) L-1 24 h-1 when the same irradiance was provided on both sides of the panels. With 230 mol photon m-2 s-1 on one side of the panel, a mean productivity of 0.85 g (d. wt) L-1 24 h-1 was achieved, which reached 1.45 g (d. wt) L-1 24 h-1 when both sides were illuminated. Increasing the amount of light provided to the culture (either by increasing irradiance or the illuminated surface area) decreased pigment and enhanced the total fatty acid content, but did not change significantly the content of eicosapentaenoic acid. A MFPP of the present dimensions could produce sufficient microalgae to support a hatchery producing 6 million sea bream fingerlings annually.