[Isolation of bacteria which could perform nitrification and denitrification simultaneously by gene probe]

The bacteria which could perform nitrification and denitrification simultaneously from nitrogen containing wastes in Taiwan were isolated by using the probes made from random DNA fragments of Thiosphaera pantotropha. Two isolates were identified and named Alcaligenes faecalis subsp. faecalis strain 1 and strain 2 respectively. The effects on nitrification and denitrification by different medium pH, oxygen content, addition of different electron donors or inhibitors were studied. The isolates not only could perform nitrification, but also denitrification even in the presence of oxygen. Potassium cyanide could inhibit denitrification; hydrazine and hydroxyamine could inhibit nitrification. Alcaligenes faecalis subsp. faecalis strain 2 shows better denitrification.