# Biodiversity and Biotechnological Potential of Dunaliella sp. Isolates from Kalloni Solar Saltworks (Lesvos, Greece)

## TL;DR

This study explores the biodiversity and biotech potential of Dunaliella microalgae from Greek saltworks, finding strains rich in proteins, carotenoids, and antioxidants.

## Contribution

The study provides new insights into the biodiversity and biochemical profiles of Dunaliella strains from Kalloni saltworks, highlighting their potential for industrial applications.

## Key findings

- Isolates from evaporation ponds were rich in proteins (up to 60.8% DW), while crystallizer pond isolates had higher carbohydrates, carotenoids, and phenolics.
- Crystallizer isolates showed elevated antioxidant activity in FRAP and TEAC assays.
- Phylogenetic analysis identified three distinct Dunaliella clades, including a divergent lineage.

## Abstract

Hypersaline solar saltworks represent unique ecological niches that harbor extremophilic microalgae with considerable biotechnological potential. Within these environments, members of the genus Dunaliella are particularly noteworthy due to their remarkable metabolic plasticity and ability to accumulate high-value biomolecules. In the present study, we investigated the biodiversity of Dunaliella in hypersaline saltworks by isolating and identifying autochthonous strains and assessing their growth kinetics and biomass biochemical composition in the context of potential biotechnological applications. Specifically, sixteen strains of Dunaliella were isolated from evaporation and crystallizer ponds of the Kalloni saltworks in Lesvos, Greece, and subjected to an integrative characterization combining morphological observations, molecular phylogenetics, growth kinetics, and biochemical profiling. Phylogenetic analyses based on four genetic markers (18S, ITS, rbcL, tufA) consistently resolved the isolates into three distinct clades: one corresponding to Dunaliella salina/D. minutissima, one to D. parva, and a third representing a clearly divergent lineage. Growth assays revealed marked variability in cell density, biomass productivity and specific growth rate, with certain strains exhibiting enhanced proliferation under controlled conditions. Biochemical analyses demonstrated distinct allocation patterns, with evaporation pond isolates comparatively enriched in proteins (up to 60.8% DW), whereas crystallizer pond isolates accumulated higher levels of carbohydrates (up to 19.0% DW), carotenoids (up to 7.34% mg g−1 DW) and phenolic compounds (up to 8.68% mg GAE g−1 DW). Antioxidant assays (FRAP, TEAC) further indicated significantly elevated reducing and radical scavenging activities among crystallizer isolates. These findings expand current knowledge on the biodiversity of autochthonous Dunaliella strains and support their potential as sustainable sources of bioactive compounds for applications in the agri-food, nutraceutical, pharmaceutical, and cosmeutical sectors.