Table 3.

PLS analysis comparing potential biomarkers correlated with CH₄ emissions.

Factor	VIP	Coefficient	Information
PHYLOGENETIC FACTORa
Methanotorris	1.69	0.14	Hydrogenotrophic methanogen
Methanobrevibacter	1.37	0.12	Hydrogenotrophic methanogen
Methanocaldococcus	1.25	0.11	Hydrogenotrophic methanogen
Methanohalophilus	1.09	−0.09	Methylotrophic methanogen
Faecalitalea	0.99	−0.09	AA
Dorea	0.90	−0.08	Acetogen
Colwellia	0.88	0.04	Alkane degrader
Opitutus	0.88	−0.03	H2 producer
Singulisphaera	0.88	−0.02	Degrader
Isosphaera	0.85	−0.03	Degrader
MICROBIAL COMMUNITY FACTOR
PCoA-2b	1.55	−0.13
Met Shannon Evenb	1.33	−0.12	Methanogen evenness
Met Shannon Divb	1.32	−0.12	Methanogen diversity
A:B	0.88	−0.01	Archaea:Bacteria ratio
PCoA-1b	0.86	−0.05
METAGENOMICS FACTORc
K00672	1.32	−0.05	Formylmethanofuran-tetrahydromethanopterin N-formyltransferase
K00581	1.08	−0.02	Tetrahydromethanopterin S-methyltransferase subunit E
K00150	1.06	−0.02	Glyceraldehyde-3-phosphate dehydrogenase (NAD(P))
K01959	1.02	−0.02	Pyruvate carboxylase subunit A
K00580	1.00	−0.01	Tetrahydromethanopterin S-methyltransferase subunit D
K01499	0.95	0.00	Methenyltetrahydromethanopterin cyclohydrolase
K00584	0.94	0.00	Tetrahydromethanopterin S-methyltransferase subunit H
K01673	0.93	−0.03	Carbonic anhydrase
K13812	0.93	0.00	Bifunctional enzyme Fae/Hps
K00123	0.92	0.01	Formate dehydrogenase, alpha subunit
K00400	0.89	0.01	Methyl coenzyme M reductase system, component A2
K00402	0.89	−0.07	Methyl-coenzyme M reductase gamma subunit
K00399	0.89	0.00	Methyl-coenzyme M reductase alpha subunit
K02118	0.87	0.01	V-type H+-transporting ATPase subunit B
K00200	0.87	0.02	Formylmethanofuran dehydrogenase subunit A
K00201	0.86	0.01	Formylmethanofuran dehydrogenase subunit B
K14128	0.85	0.03	F420-non-reducing hydrogenase subunit G
K00169	0.84	0.03	Pyruvate ferredoxin oxidoreductase, alpha subunit
K00170	0.84	0.02	Pyruvate ferredoxin oxidoreductase, beta subunit
K02117	0.84	0.02	V-type H+-transporting ATPase subunit A
K00203	0.82	0.04	Formylmethanofuran dehydrogenase subunit D
K06937	0.80	0.03	7,8-dihydro-6-hydroxymethylpterin dimethyltransferase

^aValue based on the relative abundance of the microbial genera identified as significantly correlated by PLS,

^bData obtained by calculating the Shannon diversity indices or doing a PCoA on the relative abundance of the microbial phyla,

^cValue based on the relative abundance of the genes identified as significantly correlated by PLS.