Table 5. Unifrac distance scores and p values of the denitrifier communities according to different functional genes of the three periods analysed in the MFC.

Gene	Period 1 vs.Period 2	Period 1 vs.Period 3	Period 2 vs.Period 3
narG	0.25 ns	0.13 ns	0.36 ns
napA	0.07 ns	0.41*	0.40*
nirS	0.10 ns	0.25*	0.22***
nirK	0.18 ns	0.22 ns	0.16 ns
nosZ	0.02 ns	0.04 ns	0.04 ns

The Unifrac values were calculated using amino acid deduced sequences and phylogenetic trees.

Period 1, Autotrophic with nitrate; Period 2, Heterotrophic with nitrate; Period 3, Autotrophic with nitrite; ns, not significant;

^* p<0.05;

^** p<0.01;

^*** p<0.001.