Biochemical profile of halophilous microalgae strains from high-andean extreme ecosystems (NE-Chile) using methodological validation approaches

The main goal of this work is to characterize the biochemical profile of three halophilous microalgal strains isolated from extreme ecosystems in northern Chile to assess their potential as possible sources of technological and commercial advantages. A procedure for the validation of a routine method for determining the total protein, carbohydrate, lipid and chlorophyll a (Chl-a) contents in Chlorella fusca, Dunaliella salina and Spirulina sp. has been developed. Detection limits of 10.8 μg/mg, 2.7 μg/mg and 5.6 μg/mg for total protein content and 3.5 μg/mg, 1.8 μg/mg and 8.8 μg/mg for total carbohydrate content were determined in C. fusca, D. salina and Spirulina sp., respectively. Most of the biological macromolecule levels measured in the microalgae were in accordance with the magnitude of previously reported data for other strains of the same taxa. However, lower levels than expected of lipids and Chl-a were measured in C. fusca and Spirulina sp., which may be associated with an imbalance between specific growth rates and the rate of macromolecule synthesis. The protein values measured in Spirulina sp. (52.3 ± 2.2 μg/mg DW) were close to the lower limit of the range reported in the literature for non-halophilous strains of the same genus. Except for the Chl-a quantification procedure, the analytical methods for macromolecules had a high degree of repeatability and reproducibility. The variability among repeated measurements of Chl-a was associated with auto-degradation processes during pigment extraction.