反硝化产气温和食酸菌G21及其在油田生产中的应用潜力OACSTPCD

In order to study the potential application of denitrifying gas-producing bacteria in oilfield industry,we isolated a facultative anaerobic denitrifying gas-producing strain G21 from oilfield production brines,performed phylogenetic analysis based on 16S rRNA gene sequences,detected denitrifying genes,optimized carbon source and carbon-nitrogen ratio for gas production,analyzed the composition of gas-production,and tested its application potential in oilfield industry by growing test of G21 in oilfield production brines.Strain G21 showed 99.36％similarity of 16S rRNA gene sequences with Acidovorax temperans PHL,and thus belonged to Acidovorax temperans.Strain G21 contains denitrifying genes narG,napA,nirS,norB and nosZ,which encodes membrane-bound nitrate reductase(Nar),periplasmic-bound nitrate reductase(Nap),nitrite reductase(Nir),nitric oxide reductase(Nor),and nitrous oxide reductase(Nos),respectively.Gas composition analysis showed that strain G21 could reduce nitrate to nitrous oxide and nitrogen.Saccharide is the optimal carbon source of strain G21 for gas production,with the gas-liquid ratio of gas production reaches 1∶1 in medium where carbon(glucose-COD 5 000 mg/L)to nitrogen(NaNO3-N 1000 mg/L)of 5∶1.Additionally,G21 showedhigh performance for gas production when grows in oilfield production brines,and could effectively suppress the growth of sulfate-reducing bacteria.Collectively,the complete denitrifier Acidovorax temperans strain G21 has application potential in controlling sulfate-reducing bacteria and enhancing oil recovery for oilfield industry by complete denitrification.