Niche differentiation in nitrogen metabolism among methanotrophs within an operational taxonomic unit

BMC Microbiology

Table 1 Nitrogen assimilation and tolerance per strain

	Methylomonas methanica strains							Methylomonas koyamae strains					Methylomonas lenta		Type Ib	Type II
	NCIMB 11130^T	R-45362	R-45363	R-45364	R-45371	R-45372	R-45374	NCIMB 14606^T	R-45378	R-45383	R-49799	R-49807	R-45370	R-45377	R-49797	R-45379
NaCl (+NO₃ ⁻)	100 mM	100 mM	100 mM	40 mM	100 mM	100 mM	100 mM	100 mM	100 mM	100 mM	100 mM	100 mM	200 mM	200 mM	100 mM	40 mM
NaCl (+NH₄ ⁺)	40 mM	100 mM	100 mM	40 mM	100 mM	40 mM	100 mM	100 mM	100 mM	100 mM	150 mM	100 mM	200 mM	200 mM	100 mM	40 mM
NaNO₃ & KNO₃ ^a	40 mM	40 mM	40 mM	40 mM	40 mM	40 mM	40 mM	40 mM	40 mM	40 mM	40 mM	40 mM	100 mM	100 mM	40 mM	20 mM
NH₄Cl^b	40 mM	40 mM	40 mM	40 mM	40 mM	40 mM	40 mM	100 mM	40 mM	40 mM	100 mM	40 mM	40 mM	40 mM	100 mM	40 mM
(NH₄)₂SO₄-N^b	40 mM	40 mM	40 mM	40 mM	40 mM	40 mM	40 mM	40-100 mM^c	40 mM	40 mM	100 mM	40 mM	40 mM	40 mM	100 mM	40 mM
NaNO₂	2 mM	2 mM	2 mM	2 mM	2 mM	2 mM	2 mM	2 mM	2 mM	2 mM	2 mM	2 mM	2 mM	2 mM	5 mM	-
Hydroxylamine^d	1 mM	-	1 mM	1 mM	1 mM	1 mM	-	1 mM	-	-	1 mM	-	-	-	-	1 mM
nifH presence	+	+	+	+	+	+	+	+	+	+	+	+	+	+	-	+
N₂ fixation^e	+	+	+	+	+	+	+	+	+	+	+	-	-	-	-	+

Values represent maximum concentration supporting growth of the culture (n = 2).
^aFor nitrate as sole nitrogen source, 2, 10, 20, 40, 150 and 200 mM with NaNO₃ and KNO₃ were tested. Due to a technical error, strains R-49799, R-49807, R-45370, R-45377, R-49797 and R-45379 were not tested with KNO₃ concentrations above 10 mM.
^bFor ammonium as sole nitrogen source, 2, 10, 20, 40, 150 and 200 mM NH₄Cl and (NH₄)₂SO₄-N were tested.
^cDifferent outcome for duplicates;
^dHydroxylamine tolerance was evaluated in dAMS supplemented with 0.01, 1 and 2 mM hydroxylamine;
^eUnder low O₂ tension only: +, positive and -, negative for growth based on OD_600nm values in nitrogen-free medium.

ISSN: 1471-2180