FIG 6.

PCA of the DNA and cDNA data sets and core species of the taxonomic profile based on COG functional gene categories. CE model bacteria (red open diamond): Clostridium kluyveri and Ruminococcaceae bacterium; Clostridium (): C. botulinum, C. thermocellum, C. difficile, C. carboxidivorans, C. cellulolyticum, and C. acetobutylicum; Alkaliphilus (△): A. metalliredigens and A. oremlandii; Bacteroides (●): Bacteroides sp. and B. fragilis; methanogens (■): Methanosaeta thermophila, Methanobrevibacter smithii, Methanoculleus marisnigri, Methanoregula boonei, Methanosphaera stadtmanae, Methanothermobacter marburgensis, and Methanothermobacter thermautotrophicus; Petrotoga: Petrotoga mobilis.