Comparative characterization of three Tetraselmis chui (Chlorophyta) strains as sources of nutraceuticals

Abstract

Species of the genus Tetraselmis have traditionally been used as a valuable nutritional source in aquaculture for their high fatty acid content (5-10% dry weight). Their use in nutraceutical production for humans is growing worldwide. Among them, Tetraselmis chui is generally reported in the literature as rich in polyunsaturated fatty acids (PUFAs), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). We evaluated the potential of three T. chui strains for the production of these nutraceuticals: the model strain CCAP 8/6, which is broadly used in the aquaculture industry due to its high PUFA content, and two strains (TCBG-1 and TCBG-2) isolated from Guanabara Bay (Rio de 28 Janeiro, Brazil). The two Brazilian strains grew faster than CCAP 8/6 with higher percentage of PUFAs (up to 70% of total FA at the exponential growth phase). They also produced unique fatty acids in significant quantities: TCBG-1 produced arachidonic acid (ARA) and EPA during the exponential phase (> 20% of total FA), while TCBG-2 produced these PUFAs in addition to DHA (>18% of total FA) at the late exponential phase. A two-stage growth system using co-cultures of the two Brazilian strains is proposed as an optimal model for PUFA production, based on their simultaneous scaling cultivation in photobioreactors. Furthermore, both strains are suitable candidates for upscaling in open systems in tropical regions since they are adapted to the environmental conditions in Guanabara Bay, where they form massive blooms by outcompeting other microalgae