Table 3.
Statistical correlations between overall metabolic functional categories and operational parameters.
| Mesophilic vs. thermophilic condition | Before (pre) vs. after (post) H2 addition | ||||||
|---|---|---|---|---|---|---|---|
| KEGG | |||||||
| Category | PrF | b | Category | PrF | b | ||
| Thermo | Riboflavin m. | 0.04 | 0.26 | Post | Polyketide sugar unit b. | 0.04 | 0.12 |
| Nitrotoluene degr. | 0.03 | 0.18 | Pre | Two-component sys. | 0.03 | −0.01 | |
| Peptidoglycan b. | 0.02 | 0.11 | Flagellar assembly | 0.05 | −0.01 | ||
| Flagellar assembly/Bacterial chemotaxis | 0.00 | 0.11 | Pentose phosphate pathway | 0.05 | −0.04 | ||
| Meso | Amino sugar and nucleotide sugar m. | 0.05 | −0.06 | ABC transporters/PTS sys. | 0.03 | −0.04 | |
| ABC transporters/Bacterial secretion sys. | 0.04 | −0.07 | Alanine, aspartate, glutamate/Tryptophan m. | 0.03 | −0.05 | ||
| Galactose m./Starch and sucrose m. | 0.03 | −0.10 | Nitrogen m. | 0.06 | −0.05 | ||
| Lysine degr./Tryptophan m. | 0.04 | −0.16 | Glycerophospholipid m. | 0.05 | −0.06 | ||
| Glycerophospholipid m. | 0.03 | −0.17 | Sulfur m. | 0.01 | −0.07 | ||
| Polyketide sugar b./Streptomycin b. | 0.01 | −0.35 | Glutathione m. | 0.02 | −0.09 | ||
| Ascorbate and aldarate m. | 0.01 | −0.50 | B. of unsaturated fatty acids | 0.03 | −0.13 | ||
| SEED | |||||||
| Thermo | Coenzyme M | 0.00 | 2.46 | Post | Coenzyme M | 0.02 | 0.50 |
| Phage family-specific subsys.s | 0.01 | 0.78 | B. of galactoglycans, lipopolysacharides | 0.02 | 0.05 | ||
| Hyp. associated with RecF | 0.03 | 0.77 | ATP synthases | 0.05 | 0.04 | ||
| Bacteriocins, antibacterial peptides | 0.02 | 0.57 | Dormancy and sporulation | 0.05 | 0.01 | ||
| Spore DNA protection/Dormancy, sporulation | 0.00 | 0.35 | Pre | Phosphorus M. | 0.04 | −0.03 | |
| Flagella protein/Motility and Chemotaxis | 0.01 | 0.32 | Nitrogen M. | 0.01 | −0.04 | ||
| Meso | Fatty acids, Lipids, Isoprenoids | 0.05 | −0.03 | M. of aromatic compounds/M. of central aromatic intermediates | 0.02 | −0.05 | |
| Electron donating | 0.04 | −0.05 | Protein folding | 0.04 | −0.06 | ||
| Protein m./Protein b./Arginine; urea cycle, polyamines/Ammonia as. | 0.02 | −0.09 | Stress response/Oxidative stress/Osmotic stress/Cold shock | 0.03 | −0.08 | ||
| Carbohydrates/Di- and oligosaccharides/Polysaccharides | 0.02 | −0.10 | Sulfur M./Organic sulfur as. | 0.02 | −0.08 | ||
| Stress response/Osmotic stress/Heat shock | 0.03 | −0.13 | Virulence, Disease and Defense/Invasion and intracellular resistance | 0.03 | −0.09 | ||
| Resistance to antibiotics and toxic compounds/Detoxification | 0.02 | −0.15 | Motility and chemotaxis/Flagella protein | 0.03 | −0.09 | ||
| Capsular, extracellular polysacchrides/B. of galactoglycans, lipopolysacharides | 0.01 | −0.21 | Potassium m. | 0.01 | −0.11 | ||
| Protein folding/Protein processing and modification/Two related proteases | 0.03 | −0.27 | Two related proteases | 0.03 | −0.12 | ||
| Phosphorus m./Potassium m. | 0.00 | −0.33 | Protein secretion sys. | 0.04 | −0.15 | ||
| Phospholipids/Fatty acid cluster/Hyp. lipase related to phosphatidate m. | 0.03 | −0.41 | Lipids, isoprenoids/Phospholipids/Fatty acid cluster/Hyp. Lipase | 0.02 | −0.19 | ||
| Membrane-bound hydrogenase/Probably Ybbk-related hyp. membrane proteins | 0.03 | −0.45 | Branched-chain amino acids/Glutamine, glutamate, aspartate/Ammonia as./Lysine b. | 0.03 | −0.24 | ||
| Phages, Prophages, Transposable elements/Phages, Prophages/CRISPRs | 0.03 | −0.49 | Electron accepting/ Cytochrome biogenesis/Riboflavin | 0.04 | −0.55 | ||
| Adhesion | 0.01 | −0.67 | Central carbohydrate m./Coenzyme B | 0.04 | −0.78 | ||
KEGG and SEED functional categories were analyzed in order to evaluate their statistically significant effect on operational parameters (PrF indicate p-value), i.e., temperature and H2 addition. The log ratios of values obtained for PGs abundances under thermophilic or mesophilic conditions (left) and “post/pre” H2 addition (right) are considered as dependent variables. Parameter “b” is the regression coefficient of the target category (e.g., riboflavin metabolism), expressed as number of genes, on the dependent variable. The p-value refers to the effect of a target category on the dependent variable, with p = 0.05 as threshold for statistical significance. m, metabolism; b, biosynthesis; degr, degradation; sys, system; as, assimilation; hyp, hypothetical.