Dataset Information

Nitrifying biofilms deprived of organic carbon show higher functional resilience to increases in carbon supply.

ABSTRACT: In nitrifying biofilms, the organic carbon to ammonia nitrogen (C/N) supply ratio can influence resource competition between heterotrophic and nitrifying bacteria for oxygen and space. We investigated the impact of acute and chronic changes in carbon supply on inter-guild competition in two moving bed biofilm reactors (MBBR), operated with (R1) and without (R0) external organic carbon supply. The microbial and nitrifying community composition of the reactors differed significantly. Interestingly, acute increases in the dissolved organic carbon inhibited nitrification in R1 ten times more than in R0. A sustained increase in the carbon supply decreased nitrification efficiency and increased denitrification activity to a greater extent in R1, and also increased the proportion of potential denitrifiers in both bioreactors. The findings suggest that autotrophic biofilms subjected to increases in carbon supply show higher nitrification and lower denitrification activity than carbon-fed biofilms. This has significant implications for the design of nitrifying bioreactors. Specifically, efficient removal of organic matter before the nitrification unit can improve the robustness of the bioreactor to varying influent quality. Thus, maintaining a low C/N ratio is important in nitrifying biofilters when acute carbon stress is expected or when anoxic activity (e.g. denitrification or H₂S production) is undesirable, such as in recirculating aquaculture systems (RAS).

SUBMITTER: Navada S

PROVIDER: S-EPMC7189377 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Nitrifying biofilms deprived of organic carbon show higher functional resilience to increases in carbon supply.

Navada Sharada S Knutsen Maja F MF Bakke Ingrid I Vadstein Olav O

Scientific reports 20200428 1

In nitrifying biofilms, the organic carbon to ammonia nitrogen (C/N) supply ratio can influence resource competition between heterotrophic and nitrifying bacteria for oxygen and space. We investigated the impact of acute and chronic changes in carbon supply on inter-guild competition in two moving bed biofilm reactors (MBBR), operated with (R1) and without (R0) external organic carbon supply. The microbial and nitrifying community composition of the reactors differed significantly. Interestingly ...[more]

PMID: 32346018

Similar Datasets

Project description:Ecophysiological interactions between the community members (i.e., nitrifiers and heterotrophic bacteria) in a carbon-limited autotrophic nitrifying biofilm fed only NH(4)(+) as an energy source were investigated by using a full-cycle 16S rRNA approach followed by microautoradiography (MAR)-fluorescence in situ hybridization (FISH). Phylogenetic differentiation (identification) of heterotrophic bacteria was performed by 16S rRNA gene sequence analysis, and FISH probes were designed to determine the community structure and the spatial organization (i.e., niche differentiation) in the biofilm. FISH analysis showed that this autotrophic nitrifying biofilm was composed of 50% nitrifying bacteria (ammonia-oxidizing bacteria [AOB] and nitrite-oxidizing bacteria [NOB]) and 50% heterotrophic bacteria, and the distribution was as follows: members of the alpha subclass of the class Proteobacteria (alpha-Proteobacteria), 23%; gamma-Proteobacteria, 13%; green nonsulfur bacteria (GNSB), 9%; Cytophaga-Flavobacterium-Bacteroides (CFB) division, 2%; and unidentified (organisms that could not be hybridized with any probe except EUB338), 3%. These results indicated that a pair of nitrifiers (AOB and NOB) supported a heterotrophic bacterium via production of soluble microbial products (SMP). MAR-FISH revealed that the heterotrophic bacterial community was composed of bacteria that were phylogenetically and metabolically diverse and to some extent metabolically redundant, which ensured the stability of the ecosystem as a biofilm. alpha- and gamma-Proteobacteria dominated the utilization of [(14)C]acetic acid and (14)C-amino acids in this biofilm. Despite their low abundance (ca. 2%) in the biofilm community, members of the CFB cluster accounted for the largest fraction (ca. 64%) of the bacterial community consuming N-acetyl-D-[1-(14)C]glucosamine (NAG). The GNSB accounted for 9% of the (14)C-amino acid-consuming bacteria and 27% of the [(14)C]NAG-consuming bacteria but did not utilize [(14)C]acetic acid. Bacteria classified in the unidentified group accounted for 6% of the total heterotrophic bacteria and could utilize all organic substrates, including NAG. This showed that there was an efficient food web (carbon metabolism) in the autotrophic nitrifying biofilm community, which ensured maximum utilization of SMP produced by nitrifiers and prevented buildup of metabolites or waste materials of nitrifiers to significant levels.

Dataset Information

Nitrifying biofilms deprived of organic carbon show higher functional resilience to increases in carbon supply.

Publications

Nitrifying biofilms deprived of organic carbon show higher functional resilience to increases in carbon supply.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets