# Identification and Cultivation of Biotechnologically Relevant Microalgal and Cyanobacterial Species Isolated from Sečovlje Salt Pans, Slovenia

## TL;DR

This study explores microorganisms from a hypersaline environment in Slovenia, identifying and cultivating species with potential biotechnological uses.

## Contribution

The study combines biodiversity assessment with cultivation of novel microorganisms from a unique hypersaline site.

## Key findings

- Metagenomic analysis showed shifts in microbial communities with increasing salinity.
- Several salt-tolerant microorganisms with biotechnological potential were isolated and cultivated.
- The newly established cultures form a foundation for future bioprocess development.

## Abstract

Studies of complex natural environments often focus on either biodiversity or on isolating organisms with specific properties. In this study, we sought to widen this perspective and achieve both. In particular, hypersaline ecosystems, such as the Sečovlje salt pans (Slovenia), are particularly promising sources of novel bioactive compounds, as their microorganisms have evolved adaptations to desiccation and high light intensity stress. We applied shotgun metagenomics to assess microbial biodiversity under low- and high-salinity conditions, complemented by isolation and cultivation of photosynthetic microorganisms. Metagenomic analyses revealed major shifts in community composition with increasing salinity: halophilic Archaea became dominant, while bacterial abundance decreased. Eukaryotic assemblages also changed, with greater representation of salt-tolerant genera such as Dunaliella sp. Numerous additional microorganisms with biotechnological potential were identified. Samples from both petola and brine led to the isolation and cultivation of Dunaliella sp., Tetradesmus obliquus, Tetraselmis sp. and cyanobacteria Phormidium sp./Sodalinema stali, Leptolyngbya sp., and Capilliphycus guerandensis. The newly established cultures are the first collection from this hypersaline environment and provide a foundation for future biodiscovery, production optimization, and sustainable bioprocess development. The methods developed in this study constitute a Toolbox Solution that can be easily replicated in other habitats.