DISTINCT BACTERIAL COMMUNITY ASSOCIATED WITH Microcystis aeruginosa (Kϋtzing) kϋtzing 1846 CULTURED IN DIFFERENT CULTURE MEDIA AFFECTS THE CYANOBACTEIUM COLONY AND MORPHOLOGICAL PROPERTIES

Cyanobacterial blooms with predominance of Microcystis aeruginosa is often considered a threat to human and environmental health, due to their bloom-forming and possible toxin-producing potentials; or a nuisance to recreation. The role of bacteria in influencing the growing environment of microalgae, and vice-versa has not been well described. The objective of this study was to study the bacteria community that grew with M. aeruginosa and the colony morphological properties of this cyanobacterium when cultured under different culture media. A tropical M. aeruginosa (strain UPMC-A0051) was isolated from Putrajaya Lake, Malaysia, and identified using microscopic and molecular techniques. Microcystin production profile was further examined using molecular method and the cyanobacterium was identified to be a non-microcystin producer. Next, this cyanobacterium was cultured in two different media, Blue-Green medium and Bold's Basal medium.  The associated heterotrophic bacteria were isolated and identified from the two culture media. Distinct bacteria communities associated with M. aeruginosa in the two different culture media were belonged to Actinobacteria, α.-Proteobacteria and β-Proteobacteria. Moreover, it was found that M. aeruginosa cultivated in different media with different bacteria diversity demonstrated distinct colony morphology and biomass. Distinct bacteria diversity particularly the different number of bacteria species in the two culture media possibly led to the dissimilar colony morphology of M. aeruginosa. The present study revealed insights to M. aeruginosa in adapting different nutrient conditions, which bacteria might aid in their survival ability.

Keywords: Microcystis aeruginosa, bacteria community, morphology, culture media, growth pattern.