Species identification of water microorganisms resistant to chlorine compounds

Morphological cultural features of three dominant bacterial cultures isolated from the drinking tap water and water samples taken at different stages of its post treatment at the water conditioning plant of special drink enterprise have been studied. The species composition of separated bacterial isolates was analyzed in terms of 16S rRNA gene sequences. The following bacterial species were identified: Bacillus nanhaiensis, Brevibacterium frigoritolerans, and Lysinibacillus fusiformis. Lysinibacillus fusiformis species was found to be the most resistant to chlorine. Its resistance to NaOCl at concentrations 1.4, 3, 5, and 7 mg/dm(3) varies in the range 1-98% (with the exposure duration varying from 5 to 60 min), while the remaining two isolates, Bacillus nanhaiensis and Brevibacterium frigoritolerans, showed low survival rate in the presence of NaOCl (0-16%).