[Characteristics of the DNA of active sludge adapted to various carbon sources]

Some characteristic are presented for DNA of active sludge adapted to domestic waste, diethylene glycol, mannitol and glycerol. A significant shift towards CG-type is found for the nucleotide composition of the DNA of active sludge adapted to glycerol and mannitol. The fusion curves for DNA of the active sludge evidence for the presence of some totality of molecules in it. In case of the diethylene glycol adapted active sludge DNA fusion two transitions are observed corresponding to 37.8 and 68.2 mol.% of GC-pairs, that may be explained by bimodality in distribution of the number of species of the free-living bacteria according to the DNA nucleotide composition. The fusion curves for DNA of the active ooze adapted to domestic waste, mannitol and glycerol has no clearly pronounced transitions, that may be explained by the presence of other groups of microorganisms in these sludges, besides bacteria. Heterogeneity of DNA relative to the nucleotide composition with transition to a single source of carbon decreases in the series: initial active sludge greater than active sludge adapted to mannitol greater than glycerol greater than diethylene glycol.