Table 4.

Bacterial and archaeal families in the fermentation reactors

Families	Function	Taxonomy (phylum, class)	Metabolic features	Reference
Acetobacteraceae	Acidogenesis	Proteobacteria, Alphaproteobacteria	Ferment glucose and produce acetate	[59]
Anaerolineaceae	Acidogenesis Detoxification	Chloroflexi, Anaerolineae	Some species ferment glucose; major metabolic end products are VFAs and hydrogen; involved in phenol degradation	[60, 61]
Bacillaceae	Acidogenesis Detoxification	Firmicutes, Bacilli	Some species produce acid from carbohydrates; degrades polycyclic aromatic hydrocarbons	[62]
Bacteriovoracaceae	Unclear	Proteobacteria, Deltaproteobacteria	Invade the periplasm of their prey where they grow and replicate	[63]
Caldilineaceae	Acidogenesis	Chloroflexi, Caldilineae	Some species ferment glucose; major metabolic end products succinate, lactate, acetate, CO2 and traces of hydrogen	[64]
Christensenellaceae	Acidogenesis	Firmicutes, Clostridia	Some species ferment glucose; major metabolic end products are acetate and butyrate	[65]
Comamonadaceae	Acidogenesis Detoxification	Proteobacteria, Betaproteobacteria	Some species ferment pyruvate and glucose; degrade polycyclic aromatic compounds	[59]
Clostridiaceae	Acidogenesis Detoxification	Firmicutes, Clostridia	Some species ferment glucose; metabolic end products are hydrogen, butyrate, acetate and lactate; ferment methoxylated aromatics to acids, and degrade the aromatic amino acids	[62, 66, 67]
Desulfovibrionaceae	Acetogenesis Detoxification	Proteobacteria, Deltaproteobacteria	Some species utilize lactate and pyruvate; Major metabolic end products are acetate, hydrogen and CO2; degrade aromatic aldehydes and furfural	[50, 68]
Geobacteraceae	Detoxification	Proteobacteria, Deltaproteobacteria	Aromatic compounds are used by several species	[50]
Lachnospiraceae	Acidogenesis	Firmicutes, Clostridia	Some species ferment glucose; major metabolic end products are butyrate, succinate, acetate, lactate, formate and hydrogen	[69]
Leuconostocaceae	Acidogenesis	Firmicutes, Bacilli	Some species are heterofermentative and produce lactate	[69]
Nitrospiraceae	Unclear	Nitrospirae, Nitrospira	Some species consume for sulfate reduction	[53]
Peptococcaceae	Acidogenesis	Firmicutes, Clostridia	Fermentative, and syntrophy with hydrogenotrophs	[50, 62]
Planococcaceae	Acidogenesis	Firmicutes, Bacilli	Some species ferment glucose	[69]
Porphyromonadaceae	Acidogenesis	Bacteroidetes, Bacteroidia	Some species ferment glucose; end products of glucose fermentation are acetate, hydrogen, and CO2	[53]
Propionibacteriaceae	Acidogenesis	Actinobacteria, Actinobacteria	Ferment glucose; Main metabolic end products is propionic acid	[70]
Pseudomonadaceae	Detoxification	Proteobacteria, Gammaproteobacteria	Some spices degradation the aromatic compounds	[71]
Ruminococcaceae	Acidogenesis	Firmicutes, Clostridia	Ferment glucose; metabolic end products are hydrogen and VFAs	[21]
Spirochaetaceae	Acetate-oxidizing	Spirochaetae, Spirochaetes	Major metabolic end products are hydrogen and CO2	[51]
Streptococcaceae	Acidogenesis	Firmicutes, Bacilli	Carbohydrates are fermented to produce mainly lactic acid	[62]
Synergistaceae	Acidogenesis	Synergistetes, Synergistia	Some species ferment glucose and organic acids; Metabolic end products are acetate, CO2 and hydrogen; Co-culture with the hydrogenotrophic methanogens	[72, 73]
Syntrophaceae	Acetogenesis	Proteobacteria, Deltaproteobacteria	Propionate and butyrate-utilizing bacteria; Co-culture with hydrogenotrophic methanogens	[74, 75]
Syntrophomonadaceae	Acetogenesis	Firmicutes, Clostridia	Some species utilize fatty acids of 4-18 carbon atoms; Syntrophic association with hydrogenotrophic methanogens	[69, 76, 77]
Syntrophorhabdaceae	Acetogenesis Detoxification	Proteobacteria, Deltaproteobacteria	Syntrophic degradation of aromatic compounds, and produce acetate and hydrogen	[50]
Thermotogaceae	Acidogenesis	Thermotogae, Thermotogae	Able to ferment carbohydrates and peptides	[78]
Methanobacteriaceae	Methanogenic	Euryarchaeota, Methanobacteria	Hydrogenotrophic methanogens	[52]
Methanoregulaceae	Methanogenic	Euryarchaeota, Methanomicrobia	Hydrogenotrophic methanogens	[53]
Methanosaetaceae	Methanogenic	Euryarchaeota, Methanomicrobia	Acetoclastic methanogens	[52]
Methanosarcinaceae	Methanogenic	Euryarchaeota, Methanomicrobia	Hydrogenotrophic and acetoclastic methanogens	[52]
Methanospirillaceae	Methanogenic	Euryarchaeota, Methanomicrobia	Hydrogenotrophic methanogens	[52]