Effects of flask configuration on biofilm growth and metabolites of intertidal Cyanobacteria isolated from a mangrove forest.

AIMS: A novel approach was employed to study the growth of three cyanobacterial strains namely Oscillatoria sp. (AP17), Leptolyngbya sp. (AP3b) and Chroococcus sp. (AP3U). Furthermore, their broad metabolite profile, production of pigments, exopolysaccharide (EPS) and antimicrobial activity were evaluated in response to contrasting cultivation modes: biofilm or planktonic.

METHODS AND RESULTS: The biofilm culture mode was carried out in the patented conico-cylindrical flask (CCF) and the planktonic culture mode was carried out in an Erlenmeyer flask (EF). The amount of polysaccharide that was released and that remained capsular/bound was higher in CCF compared to EF cultivation. Amount of chlorophyll a produced by Oscillatoria (AP17) was higher in the CCF compared to the EF cultivation. Highest antimicrobial activities were exhibited by Leptolyngbya (AP3b) biofilm than other biofilms as well as planktonic biomass. Metabolite profiles of Cyanobacteria were revealed by various chromatographic techniques and showed clear differences among the two contrasting modes of cultivation.

CONCLUSIONS: The results showed clear differences in the mode of growth for achieving maximum chlorophyll a, EPS and bioactive metabolite production of the Cyanobacteria.

SIGNIFICANCE AND IMPACT OF THE STUDY: The present study augmented the information which can enhance wider exploration of the biofilm mode of cultivation of Cyanobacteria.