Valorization of aquaculture streams using microalgae biotechnology to obtain mycosporine-like amino acids (MAAs)

Abstract

Recirculation Systems in Aquaculture (RAS) are undoubtedly one of the models of aquaculture production that best fit the production philosophy in terms of "Circular Economy". The RAS designs, even with a good configuration that includes different levels of complexity, can generate several water streams whose subsequent treatment must be managed by the concentration of organic matter and nutrients that they contain. These streams have a great potential for reuse and valorization, due to their concentrations of nitrogen and phosphorous. Therefore, the innovative treatment solutions of these flows should incorporate technologies to recovery these nutrients. Microalgae are the ecological basis of the trophic chains of marine ecosystems. In addition, from a productive and economic point of view, microalgae are considered the most promising raw materials for the sustainable supply of commodities, products of high value, as well as for their direct use (Pulz and Gross 2004). The valorization of industrial effluents is increasing in order to recover nutrients by using microalgae biotechnology. In this way, the biomass obtained can be used for the production of biofertilizers, biogas, bioplastics or natural products of interest (Demirbas 2009; Chew et al. 2017). Among the different products with high added value that can be obtained from microalgae, we can highlight the mycosporine-like amino acids (MAAs). They can prevent the adverse consequences caused by oxidative stress due to its strong antioxidant function or free radical elimination (Dunlap and Yamamoto 1995). From a more applied industrial biotechnology perspective, MAAs are becoming important compounds of interest to supplement and/or replace commercially available sunscreens. The MAAs synthesis is very influenced by certain abiotic factors such as UV radiation, high salinity and nutrient concentration (Rastogi et al. 2010). The purpose of this study is to asses a marine aquaculture stream of a RAS system as a culture media for Phaeodactylum tricornutum, subjecting it to different stress conditions, and to evaluate the possible production of MAAs.