Interactions Of Nitrate-Reducing Bacteria And Sulfate-Reducing Bacteria

Nitrate-reducing bacteria and sulfate-reducing bacteria coexist in the production water of reservoir. Sulfate-reducing bacteria produce hydrogen sulfide during growth, lead to souring of production water, and pipe corrosion. Nitrate-reducing bacteria would inhibit sulfide production in water samples, and weakening or inhibition of acidification of water samples and pipeline corrosion.This study analyzed the best medium for sulfate-reducing bacteria cultivation by modifying carbon, nitrogen, phosphor sources, ratio and concentration. Best medium includes: Na2HPO4·12H2O 4.35 g/L, KH2PO41.07 g/L, suger 0.57 g/L, NH4Cl0.53g/L. It shows inorganic salts and organic matter could promote the growth of SRB, and they are both essential parts of SRB medium.Molecular biology PCR-DGGE, clone libiary and two different functional genes nap A, narG which encode subunit of periplasmic nitrate reductase and membrane-bound respiratory nitrate reductase were used to study the community structure of nitrate-reducing bacteria and their response to organic carbons. It shows all the NAP sequences analyzed related to mesophilic bacteria, organic acids enrich more Enterobacteriales, alkens promote more Alphaproteobacteria.Finally, the nitrate-reducing bacteria and sulfate-reducing bacteria mixed culture were used to study the inhibitory effect of hydrogen sulfide between the process of interaction. Inhibition raises in one week, inhibition reach to 65.4%. Nitrate-reducing bacteria community were analyzed by the napA genes, all the clones related to Burkholderiales.