The physiological effect of heavy metals and volatile fatty acids on Methanococcus maripaludis S2

Table 2 Type of compounds used as potential inhibitors and its corresponding concentrations

Inhibitor type	#	Sample name	Compound and concentration
Inorganic^a	1	1Zn	Zn 1.0 mmol L⁻¹
	2	2Zn	Zn 2.4 mmol L⁻¹
	3	3Zn	Zn 3.9 mmol L⁻¹
	4	1Cu	Cu 1.9 µmol L⁻¹
	5	2Cu	Cu 4.4 µmol L⁻¹
	6	3Cu	Cu 6.3 µmol L⁻¹
Organic and organic/organic	7	1Ac	Ac 12.2 mmol L⁻¹
	8	2Ac	Ac 60.9 mmol L⁻¹
	9	3Ac	Ac 121.9 mmol L⁻¹
	10	1Pr	Pr 10.4 mmol L⁻¹
	11	2Pr	Pr 52.0 mmol L⁻¹
	12	3Pr	Pr 104.1 mmol L⁻¹
	13	1Pr1Ac	(Pr 10.4 + Ac 12.2) mmol L⁻¹
	14	2Pr1Ac	(Pr 52.0 + Ac 12.2) mmol L⁻¹
	15	3Pr1Ac	(Pr 104.1 + Ac 12.2) mmol L⁻¹
Combined inorganic/inorganic or combined inorganic/organic	16	1Zn1Cu	Zn 1.0 mmol L⁻¹ + Cu 1.9 µmol L⁻¹
	17	1Zn2Cu	Zn 1.0 mmol L⁻¹ + Cu 4.4 µmol L⁻¹
	18	1Zn3Cu	Zn 1.0 mmol L⁻¹ + Cu 6.3 µmol L⁻¹
	19	1Cu2Ac	Cu 4.4 µmol L⁻¹ + Ac 60.9 mmol L⁻¹
	20	2Cu2Ac	Cu 4.4 µmol L⁻¹ + Ac 60.9 mmol L⁻¹
	21	3Cu2Ac	Cu 6.3 µmol L⁻¹ + Ac 60.9 mmol L⁻¹
	22	1Cu3Ac	Cu 1.9 µmol L⁻¹ + Ac 121.9 mmol L⁻¹
	23	2Cu3Ac	Cu 4.4 µmol L⁻¹ + Ac 121.9 mmol L⁻¹
	24	3Cu3Ac	Cu 6.3 µmol L⁻¹ + Ac 121.9 mmol L⁻¹
	25	1Zn2Ac	(Zn 1.0 + Ac 60.9) mmol L⁻¹
	26	1Zn3Ac	(Zn 1.0 + Ac 121.9) mmol L⁻¹

Three different concentrations of Zn, provided as ZnSO₄·7H₂O (1.04, 2.4 and 3.5 mmol L⁻¹) and Cu, provided as CuSO₄ (1.9, 4.4, 6.3 µmol L⁻¹) were used individually or in combination (experiments #1–6 and #16–18). Two concentrations of acetate (60.9 and 121.9 mmol L⁻¹) were tested in addition to the recommended concentration of 12.2 mmol L⁻¹ (experiments #7–9). Propionate was tested at concentrations of 10.4, 52.0 and 104.1 mmol L⁻¹ without or with acetate was also tested (#10–15). In experiments #19–26 a combination of Zn or Cu with acetate was tested
Ac acetate, Pr propionate
^aMedium in 1–9 contained an acetate concentration of 12.2 mmol L⁻¹ as a standard nutrient for M. maripaludis growth

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