Aggregation ability of three phylogenetically distant anammox bacterial species

Abstract

Anaerobic ammonium-oxidizing (anammox) bacteria are well known for their aggregation ability. However, very little is known about cell surface physicochemical properties of anammox bacteria and thus their aggregation abilities have not been quantitatively evaluated yet. Here, we investigated the aggregation abilities of three different anammox bacterial species: "Candidatus Brocadia sinica", "Ca. Jettenia caeni" and "Ca. Brocadia sapporoensis". Planktonic free-living enrichment cultures of these three anammox species were harvested from the membrane bioreactors (MBRs). The physicochemical properties (e.g., contact angle, zeta potential, and surface thermodynamics) were analyzed for these anammox bacterial species and used in the extended DLVO theory to understand the force-distance relationship. In addition, their extracellular polymeric substances (EPSs) were characterized by X-ray photoelectron spectroscopy and nuclear magnetic resonance. The results revealed that the "Ca. B. sinica" cells have the most hydrophobic surface and less hydrophilic functional groups in EPS than other anammox strains, suggesting better aggregation capability. Furthermore, aggregate formation and anammox bacterial populations were monitored when planktonic free-living cells were cultured in up-flow column reactors under the same conditions. Rapid development of microbial aggregates was observed with the anammox bacterial population shifts to a dominance of "Ca. B. sinica" in all three reactors. The dominance of "Ca. B. sinica" could be explained by its better aggregation ability and the superior growth kinetic properties (higher growth rate and affinity to nitrite). The superior aggregation ability of "Ca. B. sinica" indicates significant advantages (efficient and rapid start-up of anammox reactors due to better biomass retention as granules and consequently stable performance) in wastewater treatment application.

Hydrophobic and adhesive patterns of lactic acid bacteria and their antagonism against foodborne pathogens on tomato surface (Solanum lycopersicumL.)

“…Ali et al . (2018) demonstrate that aggregation ability of Candidatus Brocadia sinica was due to its hydrophobic surface. Hou et al .…”

Advances and challenges of mainstream nitrogen removal from municipal wastewater with anammox‐based processes

“…Ali et al. (2018) reported that Candidatus Brocadia sinica cells have the most hydrophobic surface and fewer hydrophilic functional groups in extracellular polymeric substances, which results in a better aggregate capability than that of Candidatus Jettenia caeni and Candidatus Brocadia sapporoensis. These results implied that the existing form of anammox sludge in the bioreactor might be conspicuously related to the bacterial species of seeding sludge.…”

NMR as a “Gold Standard” Method in Drug Design and Discovery

“…The available literature [ 32 , 33 , 34 , 36 ] highlights the practicality of NMR in drug design studies. For these reasons, NMR spectroscopy is highly sought after in drug development [ 37 , 38 , 39 , 40 , 41 ], for both molecule identification [ 11 , 13 , 14 , 18 , 42 , 43 , 44 , 45 , 46 ] and structural elucidation [ 15 , 16 , 17 , 45 , 47 , 48 , 49 , 50 , 51 ]. NMR has been successfully applied in stereochemistry [ 52 , 53 , 54 , 55 , 56 ] and isomer determination [ 57 , 58 , 59 , 60 , 61 ], in drug-protein interactions studies [ 62 , 63 , 64 ], and in the evaluation of drug toxicity [ 65 , 66 , 67 , 68 ].…”