Isolation, characterization, and wastewater acclimatization of indigenous cyanobacteria with potential for halogenated hydrocarbon bioremediation

Cyanobacteria are ecologically significant photosynthetic microorganisms with high potential for environmental remediation because they are able to thrive in polluted environments and convert a variety of contaminants. The present study was aimed to study the diversity, enrichment, isolation and morphological characterization of cyanobacteria from wastewater associated aquatic ecosystem of Madhepura, Bihar, India. Water and sediment samples were taken from ponds, wetlands, irrigation channels and wastewater accumulation areas and placed in controlled laboratory conditions in BG-11 medium. Enrichment process was successful in the proliferation of cyanobacterial populations as indicated by the accumulation of biomass, characteristic blue-green pigmentation and filament formation. The five dominant cyanobacterial taxa identified by morphological characterization by light microscopy were Anabaena variabilis, Nostoc carneum, Fischerella sp., Oscillatoria sp., and Phormidium sp. Among these, Anabaena variabilis and Nostoc carneum were the most common and abundant. The biodiversity analysis showed moderate species diversity and community evenness in the ecosystems studied. The enriched cultures were successfully acclimatized to wastewater conditions and exhibited biomass accumulation during the experimental period. The findings indicate that wastewater-associated aquatic ecosystems are valuable sources of indigenous cyanobacteria with potential relevance to environmental biotechnology. However, degradation of specific halogenated hydrocarbons was not experimentally demonstrated in the present study. The identified isolates should therefore be considered candidates for future pollutant-specific investigations involving quantitative chemical analysis, degradation kinetics, and identification of transformation products.