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Sulfide alters microbial functional potential in a methane and nitrogen cycling biofilm reactor
Author(s) -
Delgado Vela Jeseth,
Bristow Laura A.,
Marchant Hannah K.,
Love Nancy G.,
Dick Gregory J.
Publication year - 2021
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.15352
Subject(s) - nitrite , anammox , biofilm , sulfide , denitrifying bacteria , environmental chemistry , ammonium , anaerobic oxidation of methane , nitrogen cycle , biology , methane , hydrogen sulfide , microbial population biology , nitrogen , denitrification , nitrate , chemistry , bacteria , ecology , sulfur , organic chemistry , genetics
Summary Cross‐feeding of metabolites between coexisting cells leads to complex and interconnected elemental cycling and microbial interactions. These relationships influence overall community function and can be altered by changes in substrate availability. Here, we used isotopic rate measurements and metagenomic sequencing to study how cross‐feeding relationships changed in response to stepwise increases of sulfide concentrations in a membrane‐aerated biofilm reactor that was fed with methane and ammonium. Results showed that sulfide: (i) decreased nitrite oxidation rates but increased ammonia oxidation rates; (ii) changed the denitrifying community and increased nitrous oxide production; and (iii) induced dissimilatory nitrite reduction to ammonium (DNRA). We infer that inhibition of nitrite oxidation resulted in higher nitrite availability for DNRA, anammox, and nitrite‐dependent anaerobic methane oxidation. In other words, sulfide likely disrupted microbial cross‐feeding between AOB and NOB and induced cross‐feeding between AOB and nitrite reducing organisms. Furthermore, these cross‐feeding relationships were spatially distributed between biofilm and planktonic phases of the reactor. These results indicate that using sulfide as an electron donor will promote N 2 O and ammonium production, which is generally not desirable in engineered systems.