Background:

Microalgae and cyanobacteria are potential sources of new applications with biological activity. In our country, the research on applications of these organisms is still incipient.

Objective:

To test the potential of some species of microalgae and cyanobacteria as erythrocytes agglutinins (presence of lectins) and bactericides, considering the influence of the systems and media of cultivation and production of these microscopic organisms.

Methods:

Nine species to be tested were grown in different systems: photobioreactors of 8 and 16 L and raceway tanks of 300 and 3000 L, using Bayfoland forte ®, F / 2, UTEX, Zarrouk and modified Jourdan cultivation media, the obtained biomass was lyophilized for testing. Lectins detection (agglutination tests) was performed as recommended by Muñoz et al. (1985) and for antibiosis tests, the recommendations of Bauer et al. (1966) were followed.

Results:

Three species (two chlorophytes and one cyanobacteria) induced potent agglutination of erythrocytes, a dependence on the cultivation system to increase the total activity was observed when organisms were grown in raceways. Only one species of the microalgae studied showed mild antibacterial activity, this was against Pseudomonas aeruginosa.

Conclusions:

Bacteriostatic activity of Desmodemus quadricauda extract against Pseudomonas aeruginosa and agglutination of Tetradesmus obliquus, Desmodesmus quadricauda and Arthrospira platensis species are reported. Emphasizing that there are three potential species that provide lectins since they strongly agglutinated the erythrocytes without enzymatic treatment.