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Comammox Functionality Identified in Diverse Engineered Biological Wastewater Treatment Systems
Citation:
Annavajhala, M., V. Kapoor, J. Santodomingo, AND K. Chandran. Comammox Functionality Identified in Diverse Engineered Biological Wastewater Treatment Systems. Environmental Science & Technology Letters. American Chemical Society, Washington, DC, 5(2):110-116, (2018).
Impact/Purpose:
This study provides novel information on the presence of different bacterial groups present in wastewater that are capable of oxidizing ammonia under different oxygenic conditions. Complete ammonia oxidation (comammox) to nitrate in certain Nitrospira-lineage bacteria (CMX) could be problematic to engineered biological nitrogen removal (BNR) processes due to the ability of CMX to compete for substrates with ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB), and anaerobic ammonia oxidizing (anammox) bacteria (AMX). A global metagenomic survey was conducted to quantify the presence and elucidate potential functionality of CMX in sixteen full-scale BNR reactor configurations treating mainstream or sidestream wastewater. Coding regions from the three annotated CMX and two recently annotated AMX were combined with previously published AOB, NOB, and AMX genomes to create an expanded database of protein sequences for alignment of metagenomic reads. Despite high variability in microbial ecology, CMX species consistently accounted for between 0.28 and 0.64% of total coding DNA sequences (CDS). Both the relative contribution to overall functional capacity and the presence of key functional genes (nitrite oxidoreductase (NXR), ammonia monooxygenase (AMO), and hydroxylamine oxidoreductase (HAO)) supported the theorized advantage of CMX over NOB, yet not AOB, in biofilms through prioritization of growth yield over rate. Ultimately, the near-ubiquitous presence of CMX bacteria and metabolic functionality in such diverse systems emphasizes the need to translate novel bacterial transformations to engineered biological process design.
Description:
Complete ammonia oxidation (comammox) to nitrate in certain Nitrospira-lineage bacteria (CMX) could be problematic to engineered biological nitrogen removal (BNR) processes due to the ability of CMX to compete for substrates with ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB), and anaerobic ammonia oxidizing (anammox) bacteria (AMX). A global metagenomic survey was conducted to quantify the presence and elucidate potential functionality of CMX in sixteen full-scale BNR reactor configurations treating mainstream or sidestream wastewater. Coding regions from the three annotated CMX and two recently annotated AMX were combined with previously published AOB, NOB, and AMX genomes to create an expanded database of protein sequences for alignment of metagenomic reads. Despite high variability in microbial ecology, CMX species consistently accounted for between 0.28 and 0.64% of total coding DNA sequences (CDS). Both the relative contribution to overall functional capacity and the presence of key functional genes (nitrite oxidoreductase (NXR), ammonia monooxygenase (AMO), and hydroxylamine oxidoreductase (HAO)) supported the theorized advantage of CMX over NOB, yet not AOB, in biofilms through prioritization of growth yield over rate. Ultimately, the near-ubiquitous presence of CMX bacteria and metabolic functionality in such diverse systems emphasizes the need to translate novel bacterial transformations to engineered biological process design.
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Comammox functionality in Diverse Engineered Biological Wastewater Treatment Systems