Cultivable Bacterial Diversity of Alkaline Lonar Lake, India

• Published in: Microbial ecology 2008-02, Vol.55 (2), p.163-172
• Main Authors: Joshi, Amarja A, Kanekar, Pradnya P, Kelkar, Anita S, Shouche, Yogesh S, Vani, Aijaz A, Borgave, Suchitra B, Sarnaik, Seema S
• Format: Article
• Language: English
• Subjects: Actinobacteria; Alcaligenes; Bacillus; Bacteria; Bacteria - classification; Bacteria - genetics; Bacteria - isolation & purification; Biodiversity; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Colony Count, Microbial; Dietzia; DNA, Bacterial - genetics; DNA, Ribosomal - genetics; Ecology; Enterococcus; Enzymes; Exiguobacterium; Firmicutes; Fundamental and applied biological sciences. Psychology; Geoecology/Natural Processes; Geologic Sediments - microbiology; Halomonas; Hydrogen-Ion Concentration; India; Lakes; Lentic systems; Life Sciences; Microbial Ecology; Microbiology; Micrococcus; Microorganisms; Molecular Sequence Data; Nature Conservation; Original Article; Paenibacillus; Paracoccus; Phylogenetics; Phylogeny; Planococcus; Proteobacteria; Providencia; RNA, Ribosomal, 16S - genetics; Salt tolerance; Sediment samplers; Sediments; Sequence Analysis, DNA; Soil Microbiology; Stenotrophomonas; Vagococcus; Water analysis; Water Microbiology; Water Quality/Water Pollution; Water sampling
• ISSN: 0095-3628; 1432-184X
• DOI: 10.1007/s00248-007-9264-8

Aerobic, alkaliphilic bacteria were isolated and characterized from water and sediment samples collected in the winter season, January 2002 from alkaline Lonar lake, India, having pH 10.5. The total number of microorganisms in the sediment and water samples was found to be 10²-10⁶ cfu g-¹ and 10²-10⁴ cfu ml-¹, respectively. One hundred and ninety-six strains were isolated using different enrichment media. To study the bacterial diversity of Lonar lake and to select the bacterial strains for further characterization, screening was done on the basis of pH and salt tolerance of the isolates. Sixty-four isolates were subjected to phenotypic, biochemical characterization and 16S rRNA sequencing. Out of 64, 31 bacterial isolates were selected on the basis of their enzyme profile and further subjected to phylogenetic analysis. Phylogenetic analysis indicated that most of the Lonar lake isolates were related to the phylum Firmicutes, containing Low G+C, Gram-positive bacteria, with different genera: Bacillus, Paenibacillus, Alkalibacillus, Exiguobacterium, Planococcus, Enterococcus and Vagococcus. Seven strains constituted a Gram-negative bacterial group, with different genera: Halomonas, Stenotrophomonas and Providencia affiliated to γ-Proteobacteria, Alcaligenes to β-Proteobacteria and Paracoccus to α-Proteobacteria. Only five isolates were High G+C, Gram-positive bacteria associated with phylum Actinobacteria, with various genera: Cellulosimicrobium, Dietzia, Arthrobacter and Micrococcus. Despite the alkaline pH of the Lonar lake, most of the strains were alkalitolerant and only two strains were obligate alkaliphilic. Most of the isolates produced biotechnologically important enzymes at alkaline pH, while only two isolates (ARI 351 and ARI 341) showed the presence of polyhydroxyalkcanoate (PHA) and exopolysaccharide (EPS), respectively.