2 research outputs found
Insight into c‑di-GMP Regulation in Anammox Aggregation in Response to Alternating Feed Loadings
Substrate
concentrations generally fluctuate in wastewaters. However,
how anammox biomass behaves to overcome the stress of alternating
feed loadings remains unclear. Here, we combined long-term reactor
operation, batch tests, 16S rRNA transcript sequencing, and metabolomics
analysis to investigate the aggregation of anammox biomass under the
regulation of c-di-GMP, a key second messenger, in response to alternating
feed loadings. We demonstrated that the aggregation process was significantly
faster under alternating loadings and was significantly correlated
with higher levels of c-di-GMP and extracellular polymeric substances
(EPS) production. The increase in c-di-GMP was positively correlated
with a higher relative transcript expression level in the c-di-GMP
pathway-dependent community. The targeted metabolomics results indicated
that the increased production of fructose 6-phosphate and UDP-<i>N</i>-acetyl-d-glucosamine, the precursor substances
for the synthesis of exopolysaccharides, was induced by higher levels
of c-di-GMP. Consequently, the granulation process was accelerated
via EPS production. Higher levels of intracellular hydrophobic amino
acids were also positively correlated with increased extracellular
protein levels, considering the significant increase in peptides under
alternating loadings. On the basis of our findings, we believe that
c-di-GMP regulation and EPS production of the anammox biomass are
important mechanisms to enhance its tolerance against unfavorable
feed stress. These results highlight the role of c-di-GMP in anammox
biomass as it works to survive in unfavorable niches
Insight into c‑di-GMP Regulation in Anammox Aggregation in Response to Alternating Feed Loadings
Substrate
concentrations generally fluctuate in wastewaters. However,
how anammox biomass behaves to overcome the stress of alternating
feed loadings remains unclear. Here, we combined long-term reactor
operation, batch tests, 16S rRNA transcript sequencing, and metabolomics
analysis to investigate the aggregation of anammox biomass under the
regulation of c-di-GMP, a key second messenger, in response to alternating
feed loadings. We demonstrated that the aggregation process was significantly
faster under alternating loadings and was significantly correlated
with higher levels of c-di-GMP and extracellular polymeric substances
(EPS) production. The increase in c-di-GMP was positively correlated
with a higher relative transcript expression level in the c-di-GMP
pathway-dependent community. The targeted metabolomics results indicated
that the increased production of fructose 6-phosphate and UDP-<i>N</i>-acetyl-d-glucosamine, the precursor substances
for the synthesis of exopolysaccharides, was induced by higher levels
of c-di-GMP. Consequently, the granulation process was accelerated
via EPS production. Higher levels of intracellular hydrophobic amino
acids were also positively correlated with increased extracellular
protein levels, considering the significant increase in peptides under
alternating loadings. On the basis of our findings, we believe that
c-di-GMP regulation and EPS production of the anammox biomass are
important mechanisms to enhance its tolerance against unfavorable
feed stress. These results highlight the role of c-di-GMP in anammox
biomass as it works to survive in unfavorable niches