Table 4.
List of the Enzymes/genes identified in AB4 polluted system involved in heavy metal resistance and transport/regulation of macronutrients and their taxonomic affiliations
| Macronutrients | Enzymes/genes | Microorganisms |
|---|---|---|
| Sulfur | Sulfate permease and related transporters (MFS superfamily); arylsulfatase A and related enzymes; sulfate/thiosulfate transporter subunit; alkanesulfonate transporter, permease subunit; sulfonate transport system | Xanthomonas, Roseomonas, Zhongshania, Polyangium brachysporum |
| Nitrogen and potassium | NAD(P)H-nitrite reductase, ferredoxin subunits of nitrite reductase and ring hydroxylating enzymes; glutamate synthase (NADPH/NADH) large chain; Kef-type K+ transport system, membrane component; glutathione-regulated potassium efflux system protein KefC | Sphingopyxis, Pseudomonas geniculata, Paracoccus |
| Phosphorus and multiple cations transport | Cation transport ATPase, two-component system OmpR family, response regulator PhoP; two component system, OmpR family, phosphate regulon sensor histidine kinase PhoR; ABC-type nitrate/sulfonate/bicarbonate transport system, permease component | Candidatus Accumulibacter, Oblitimonas, Pseudoxanthomonas, Polyangium brachysporum |
| Metal resistance/transport genes | ||
| Iron | ABC-type Fe3+-hydroxamate transport system, periplasmic component; Outer membrane receptor for ferrienterochelin and colicins, FepA; siderophore synthetase component; ferrichrome/ferrioxamine B periplasmic transporter; ABC.FEV.S, iron complex transport system substrate-binding protein; ofuC, fbpC, Fe3+ transport system ATP-binding protein; TC.FEV.OM, iron complex outer membrane receptor protein; bacterioferritin | Stenotrophomonas, Pseudomonas, Gluconacetobacter, Zhongshania, Phenylobacterium |
| Cadmium, lead, zinc, mercury and manganese | Zinc/cadmium/mercury/lead transporting ATPase; Cd2+/Zn2+-exporting ATPase, zntA; Mn2+ and Fe2+ transporters of the NRAMP family; manganese transport protein, MntH | Candidatus Accumulibacter, Pseudomonas geniculata |
| Copper and silver | Putative silver efflux pump; CueR, MerR family transcriptional regulator, copper efflux regulator; Cu(I)/Ag(I) efflux system membrane protein CusA/SilA | Stenotrophomonas, Immundisolibacter, Dyella |