Table 1. Source of hydrocarbon-degrading methanogenic cultures and enrichment conditions.

	NAPDC	SCADC	TOLDC
In situ conditions in environment
Sample environment	Mature fine tailings in oil sands tailings ponda	Mature fine tailings in oil sands tailings ponda	Gas condensate-contaminated aquifer sedimentsb
Location	Alberta, Canada	Alberta, Canada	Colorado, USA
Depth (m below surface)	31 m	35 m	1.5 m
Bulk pH	7–8	7–8	7–8
Temperature	12–20 °C	12–20 °C	15–20 °C
Redox condition	Anoxic	Anoxic	Anoxic
Incubation conditions for enrichment cultures
Initial inoculum %	50% (v/v)	50% (v/v)	30% (v/v)
Number of transfers	2	4	>10
Inoculum proportion transferred	10% (v/v)	50% (v/v)	30% (v/v)
Substrate	0.2% (v/v) Naphtha	0.1% (v/v) C6-C10 n-alkanesc	0.01% (v/v) Toluene
Culture medium	Anoxic mineral mediumd	Anoxic mineral mediumd	Anoxic mineral mediume
Initial medium pH	7–8	7–8	7–8
Initial headspace gas	20/80% (v/v) CO2/N2	20/80% (v/v) CO2/N2	20/80% (v/v) CO2/N2
Incubation temperature	28 °C	28 °C	20–25 °C
Incubation time (before DNA extraction)	120 days	120 days	150 days
Light exposure	Dark	Dark	Dark

Abbreviations: NAPDC, naphtha-degrading culture; SCADC, short chain alkane-degrading culture; TOLDC, toluene-degrading culture.

^aMildred Lake Settling Basin, Alberta, Canada (Siddique et al., 2007).

^bFt. Lupton, Colorado, USA (Fowler et al., 2012).

^cIncludes minor proportions of 2-methylpentane, 3-methylpentane and methylcyclopentane (Tan et al., 2013).

^dPer Widdel and Bak (1992) (anoxic freshwater mineral salts medium).

^ePer McInerney et al. (1979) (anoxic freshwater mineral salts medium).