Stefania Patsialou1,4, Panagiotis Dritsas2, Yannis Kotzamanis3, George Aggelis2, Athanasia G. Tekerlekopoulou1, Dimitris V. Vayenas4
1 Department of Sustainable Agriculture, School of Agricultural Sciences, University of Patras, 30100 Agrinio, Greece
2 Department of Biology, School of Natural Sciences, University of Patras, 26500 Patras, Greece 3 Hellenic Centre for Marine Research/Institute of Marine Biology, Biotechnology and Aquaculture, 19013 Anavyssos, Greece
4 Department of Chemical Engineering, School of Engineering, University of Patras, 26500 Patras, Greece
In recent years there is a great interest for high added value bioproducts derived from marine microalgae. These valuable metabolic compounds (e.g. lipids, carbohydrates, pigments, proteins), are well known for their potential use in biotechnological applications in various fields, such as pharmaceuticals, cosmetic products, human and animal nutrition and the production of renewable energy sources. In this work four different marine microalgae species (isolated from coastal areas of the Ionian Sea) were cultivated in a paddle wheel, open, raceway pond photobioreactor (PBR) of 40 L operating volume. Specifically, the strains Nephroselmis pyriformis, Picochlorum costavermella, Picochlorum oklahomense and Nannochloropsis gaditana were examined. Initially, stock cultures of strains were gradually scaled up from 100 ml flasks to 6L aquariums with the aim to inoculate the raceway pond. It should be mentioned that the growth medium was sterile artificial seawater of salinity 33 ‰. In all experiments the pH was remained at the value of about 8.5, the temperature was 23oC ±1oC, while continuous illumination (2000-2500 lux) was employed from three LED lamps. Also, the culture was circulated in the pond using a double 4-bladed paddlewheel driven by an electric motor rotating at 35 rpm. Biomass growth was examined for all the above-mentioned microalgae strains, for a period of 19 days. N. pyriformis and P. costavermella presented similar final biomass concentration, 419.1±79.9 mg/L and 405.7±0.2, respectively, while N. gaditana reached a lower value, that of 359.5±42.7 mg/L. An even lower value (212.9±11.4 mg/L) was presented for P. oklahomense. Lipid content was varied greatly by species, with values of 30.7±4.5, 64.7±0.3, 75.2±5.9 and 28.3±3.8 mg/L, for N. pyriformis, N. gaditana, P. costavermella and P. oklahomense, respectively. The final produced biomass will also be characterized for its protein, polysaccharide, amino acid and pigment content, in order to assess the use of biomass in various biotechnological applications.
Keywords: marine microalgae, Ionian Sea, bioproducts