Table 1.

Acetylene-reducing activities of strain YA01 and its closest relatives, Caldicellulosiruptor hydrothermalis 108 and Caldicellulosiruptor kronotskyensis 2002 in the absence and presence of ammonium at 70°C.

Strains		YA01			C. hydrothermalis 108			C. kronotskyensis 2002
Conditions*		ΔNH4+	+NH4+		ΔNH4+	+NH4+		ΔNH4+	+NH4+
Acetylene-reducing activity (nmol C2H4 106 cells–1 24 h–1)**		610±246	18.8±14.3		107±18.3	0.257±0.0694		363±74.4	216±156

*, ΔNH₄⁺, modified Winogradsky’s nitrogen-poor mineral medium; +NH₄⁺, ammonium-containing medium (2‍ ‍mmol L^–1 of NH₄Cl).

**, values were obtained from three culture vials and shown with standard deviations.