Microalgae are microscopic algae, typically found in freshwater and marine systems. They are unicellular species which exist individually, or in chains or groups. Depending on the species, their sizes can range from a few micrometers (µm) to a few hundreds of micrometers. Unlike higher plants, microalgae do not have roots, stems and leaves. Microalgae, capable of performing photosynthesis, are important for life on earth; they produce approximately half of the atmospheric oxygen and use simultaneously the greenhouse gas carbon dioxide to grow photoautotrophically. 
The biodiversity of microalgae is enormous and they represent an almost untapped resource. It has been estimated that about 200,000-800,000 species exist of which about 50,000 species are described
Microalgae produce a vast number of different bioactive compounds with interesting biotechnological and clinical applications. In this project, 6,800 microalgae species will be deeply screened specifically for new antibacterial and antibiofilm molecules.
Microalgae species adapted for growing conditions in all types of waters (salty, brackish, fresh), and temperatures (ranging from polar to tropical and even extremely hot conditions) will be investigated. They are also adapted to diverse light intensities (surface waters, symbiosis inside animals and deep waters), and are able to survive at pH ranges from 0 to over 11. All metabolic possibilities (autotrophic, heterotrophic and mixotrophic) will be covered. Based on this huge genetic richness, the probability of finding new lead molecules targeting bacteria is very high, as all sequenced microalgae till date shown different secondary metabolites pathways.
