Figure 1.
Time course of methane production at different temperatures.
A: 35°C; B: 55°C. Arrows indicate sampling points for construction of clone libraries. • and ▴: Cultures were grown in triplicate, error bars represent the standard deviation. ▪: Cultures were grown in duplicate, error bars represent the standard deviation.
Figure 2.
Gas chromatograms of the saturated hydrocarbon factions of crude oil.
A: 35°C; B: 55°C. Pr: pristane; Ph: phytane; nC17: n-heptadecane; nC18: n-octadecane; IS: d50-n-tetracosane. The crude oil samples were collected from the crude oil-degrading cultures at different time points, with the exception that “sterilized-330 days” crude oil was sampled from the second control after 330 days of incubation at 35°C, and “sterilized-303 days” crude oil was sampled from the second control after 303 days of incubation at 55°C.
Table 1.
Changes in group composition and biomarker ratios of crude oil during methanogenic degradation.
Figure 3.
The archaeal T-RFLP profiles at 35°C (A) and 55°C (B).
Crude oil -: consortium without crude oil addition; crude oil +: consortium with crude oil addition. Error bars represent the standard deviation, three replicates in crude oil-amended consortium and duplicates in crude oil-free consortium.
Figure 4.
Phylogenetic affiliation of archaeal 16S rRNA gene sequences of the methanogenic crude oil-degrading consortia.
A: 35°C; B: 55°C. The number in the column indicates the major OTUs represented by specific T-RFs, followed by the number in parentheses indicating the clone numbers of each OTU.
Figure 5.
Bacterial T-RFLP profiles at 35°C (A) and 55°C (B).
Crude oil -: consortium without crude oil addition; Crude oil +: crude oil amended consortium. Error bars represent the standard deviation, three replicates in crude oil-amended consortium and duplicates in crude oil-free consortium.
Figure 6.
Redundancy analysis of bacterial TRFLP profiles versus methane production in methanogenic oil-degrading consortia at 35°C (A) and 55°C (B).
Bold arrow denotes the explanatory variable of methane production. Values on the axes indicate the percentages of total variation explained by each axis.
Figure 7.
Phylogenetic affiliation of bacterial 16S rRNA gene sequences of the methanogenic crude oil-degrading consortia.
A: 35°C; B: 55°C. The number in the column indicates the major OTUs represented by specific T-RFs, followed by the number in parentheses indicating the clone numbers of each OTU.