Dairy wastewater as growth substrate for biomass and biocompound production by Spirulina platensis

Spirulina former Arthrospira is a Cyanobacteria with economic applications in agriculture, biofuel production and wastewater management. In order to evaluate the suitability of organic carbon containing wastewater for the production of biomass and biocompounds by Spirulina platensis (UTEX) strain was grown in three different culture media: water with inorganic carbon as sodium bicarbonate and carbonate (SAG media from the Culture Collection of Algae from Göttingen University), modified SAG media where inorganic carbon was replaced by lactic acid, and sea water enriched with lactic acid. Growth responses, morphological parameters (degree of spiralisation), chlorophyll and phytohormone production were assessed. The phytohormone analysis revealed the presence of jasmonic (JA), indole acetic (IAA) and phenylacetic (PAA) acids, and benzylaminopurine (BA) in the Spriulina strains. Spirulina biomass production was similar in all media. The salinity of seawater caused enhancement of spiralization as a possible stress response. Our results support the view that Spirulina may be an efficient organism for biomass production on wastewater from the food industry characterized by high salinity and rich in organic carbon. This type of wastewater can be a low cost substrate for achieving large-scale renewable energy production by the cultivation of Spirulina. Moreover, this technology may provide high-valued bioproducts.