Frontiers in Microbiol 11_01073 - NSmith et al 290520.pdf (835.95 kB)

Competition for hydrogen prevents coexistence of human gastrointestinal hydrogenotrophs in continuous culture

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journal contribution
posted on 2023-05-03, 18:40 authored by Nick Smith, Paul ShortenPaul Shorten, Eric Altermann, Nicole Roy, Warren McNabb
Understanding the metabolic dynamics of the human gastrointestinal tract (GIT) microbiota is of growing importance as research continues to link the microbiome to host health status. Microbial strains that metabolize hydrogen have been associated with a variety of both positive and negative host nutritional and health outcomes, but limited data exists for their competition in the GIT. To enable greater insight into the behaviour of these microbes, a mathematical model was developed for the metabolism and growth of the three major hydrogenotrophic groups: sulphate-reducing bacteria (SRB), methanogens and reductive acetogens. In batch culture simulations with abundant sulphate and hydrogen, the SRB outcompeted the methanogen for hydrogen due to having a half-saturation constant 106 times lower than that of the methanogen. The acetogen, with a high model threshold for hydrogen uptake of around 70 mM, was the least competitive. Under high lactate and zero sulphate conditions, hydrogen exchange between the SRB and the methanogen was the dominant interaction. The methanogen grew at 70% the rate of the SRB, with negligible acetogen growth. In continuous culture simulations, both the SRB and the methanogen were washed out at dilution rates above 0.15 h−1 regardless of substrate availability, whereas the acetogen could survive under abundant hydrogen conditions. Specific combinations of conditions were required for survival of more than one hydrogenotroph in continuous culture, and survival of all three was not possible. The stringency of these requirements and the inability of the model to simulate survival of all three hydrogenotrophs in continuous culture demonstrates that factors outside of those modelled are vital to allow hydrogenotroph coexistence in the GIT.


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© 2020 Smith, Shorten, Altermann, Roy and McNabb. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.


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Journal title

Frontiers in Microbiology




Smith, N. W., Shorten, P. R., Altermann, E., Roy, N. C., & McNabb, W. C. (2020). Competition for hydrogen prevents coexistence of human gastrointestinal hydrogenotrophs in continuous culture. Frontiers in Microbiology, 11, 1073. doi:10.3389/fmicb.2020.01073

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