Productie van zoutwateralgen voor toepassingen in food (en feed) deelrapport II: Werkpakketten 1&2 van project Foodgrade productie van zoutwateralgen: deelrapport II: Batchexperimenten met zoute reststromen en verschillende mariene algensoorten

There is a lot of interest in the commercial production of microalgae for food applications. Producing marine microalgae in reactors with LED lights has several advantages. Marine microalgae contain valuable components such as antioxidants, and high salinity levels in production systems can prevent contaminations with other organisms. Production in closed systems at different light wavelengths (colours) can result in high biomass concentrations and better control of biomass growth and production of valuable components. Several industries produce salt waste streams, often with associated processing costs. In this report a number of these streams is discussed (liquid fraction of cattle manure biogas slurry, potassium and sodium brines from dairy industries, brackish groundwater, seawater, purge water and brine from salt processing). An option for reducing costs (for disposal or treatment) is the production of marine microalgae on these streams. The algae can be used as food (ingredient). This report describes batch experiments in which growth of nine microalgae species was tested on these waste streams: Nannochloropsis gaditana, Phaeodactylum tricornutum, Tetraselmis chuii (two strains), Porphyridium purpureum, Dunaliella salina, Odontella aurita, Arthrospira platensis and Tetraselmis tetrathele. The experiments were performed in well plates and 1 L reactors with artificial (LED) lights. From the tests it was concluded that several of the algae species can be cultured on different waste streams. The best results were obtained with N. gaditana, A. platensis, P. purpureum en T. chuii (AF&F) on (diluted) brines from the dairy industry and the diluted liquid fraction of biogas slurry. It is recommended to optimize some of these combinations further in experiments.