抄録
Nitrate is of significance in aquatic environments, being a possible substrate both for dissimilatory ammonification and denitrification. In this report, amain attention has been focused on the endproducts of nitrare/nitrite dissimilation by bacterial isolates from river water and sewage related samples.50-60% of the isolates accumulated NO2-from NO3-; i.e, nitrate-reducing bacteria predominated in raw sewage and polluted river watersamples.4-26% of the isolates produced N2gasfrom NO3-; i. e., denitrifying bacteria predominatedin settling sewge which was contaminated by activated sludge.2-4% of the isolates produced N2 gas from NO2-, but not from NO3-; i.e., the NO2-depending denitrifiers. About 5 times larger numbers of denitrifying bacteria were detected by using Nitrate broth than by using Giltay broth. Thisresult is considered to be an evidence that the Nitrate broth supports the growth of wide variety ofdenitrifying species of bacteria. Most of the denitrifying isolates were belong to the genera Pseudomonasand A Icaligenes.The ammonifying groups of bacteria were the following fermentators: A eromonas, Klebsiella, EscherichiaandVibrio-like. Afew of theAeromonasisolates could produced gas both in the Nitrate broth and the OF test ager.
