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Lookup NU author(s): Dr Rebeca Gonzalez-Cabaleiro, Professor Thomas CurtisORCiD, Dr Dana OfiteruORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2019 The Authors The currently accepted biochemistry and bioenergetics of ammonia-oxidizing bacteria (AOB) show an inefficient metabolism: only 53.8% of the energy released when a mole of ammonia is oxidised and less than two of the electrons liberated can be directed to the autotrophic anabolism. However, paradoxically, AOB seem to thrive in challenging conditions: growing readily in virtually most aerobic environment, yet limited AOB exist in pure culture. In this study, a comprehensive model of the biochemistry of the metabolism of AOB is presented. Using bioenergetics calculations and selecting the minimum estimation for the energy dissipated in each of the metabolic steps, the model predicts the highest possible true yield of 0.16 gBio/gN and a yield of 0.13 gBio/gN when cellular maintenance is considered. Observed yields should always be lower than these values but the range of experimental values in literature vary between 0.04 and 0.45 gBio/gN. In this work, we discuss if this variance of observed values for AOB growth yield could be understood if other non-considered alternative energy sources are present in the biochemistry of AOB. We analyse how the predicted maximum growth yield of AOB changes considering co-metabolism, the use of hydroxylamine as a substrate, the abiotic oxidation of NO, energy harvesting in the monooxygenase enzyme or the use of organic carbon sources.
Author(s): Gonzalez-Cabaleiro R, Curtis TP, Ofiteru ID
Publication type: Article
Publication status: Published
Journal: Water Research
Year: 2019
Volume: 154
Pages: 238-245
Print publication date: 01/05/2019
Online publication date: 10/02/2019
Acceptance date: 18/01/2019
Date deposited: 04/03/2019
ISSN (print): 0043-1354
ISSN (electronic): 1879-2448
Publisher: Elsevier Ltd
URL: https://doi.org/10.1016/j.watres.2019.01.054
DOI: 10.1016/j.watres.2019.01.054
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