Five forward and six reverse nosZ primer candidates
were found (Table 3, Fig. 1c). For the nosZ primers,
Nos661F and Nos1773R, small modifications were tested
but in Table 1 only the best result, which was from
the original primers, is shown. None of the nosZ primer
sets resulted in fragments from the non-denitrifying
strains. The best combination was shown to be primers
nosZ-F [18] and nosZ1622R, which was designed in the
present study. Together they amplified the correct
fragment in 25 of the 28 denitrifying bacterial strains
and in all environmental samples.