Open AccessMolecular characterization and in situ quantification of anoxic arsenite‐oxidizing denitrifying enrichment cultures
Author(s) -
Sun Wenjie,
SierraAlvarez Reyes,
Fernandez Nuria,
Sanz Jose Luis,
Amils Ricardo,
Legatzki Antje,
Maier Raina M.,
Field Jim A.
Publication year - 2009
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2009.00653.x
Subject(s) - biology , anoxic waters , denitrifying bacteria , arsenite , in situ , oxidizing agent , environmental chemistry , enrichment culture , denitrification , ecology , bacteria , paleontology , arsenic , nitrogen , physics , materials science , quantum mechanics , metallurgy , chemistry , organic chemistry , meteorology
To explore the bacteria involved in the oxidation of arsenite (As(III)) under denitrifying conditions, three enrichment cultures (ECs) and one mixed culture (MC) were characterized that originated from anaerobic environmental samples. The oxidation of As(III) (0.5 mM) was dependent on NO 3 − addition and N 2 formation was dependent on As(III) addition. The ratio of N 2 –N formed to As(III) fed approximated the expected stoichiometry of 2.5. A 16S rRNA gene clone library analysis revealed three predominant phylotypes. The first, related to the genus Azoarcus from the division Betaproteobacteria , was found in the three ECs. The other two predominant phylotypes were closely related to the genera Acidovorax and Diaphorobacter within the Comamonadaceae family of Betaproteobacteria , and one of these was present in all of the cultures examined. FISH confirmed that Azoarcus accounted for a large fraction of bacteria present in the ECs. The Azoarcus clones had 96% sequence homology with Azoarcus sp. strain DAO1, an isolate previously reported to oxidize As(III) with nitrate. FISH analysis also confirmed that Comamonadaceae were present in all cultures. Pure cultures of Azoarcus and Diaphorobacter were isolated and shown to be responsible for nitrate‐dependent As(III) oxidation. These results, taken as a whole, suggest that bacteria within the genus Azoarcus and the family Comamonadaceae are involved in the observed anoxic oxidation of As(III).