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Data for: Linking cell size, Vmax, and Km in phototrophs and chemotrophs: Insights from Bayesian inference

Sasaki, Risa1; Seto, Mayumi1

Published Jun 17, 2025 on Dryad. https://doi.org/10.5061/dryad.s4mw6m9h2

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Jun 17, 2025 version files 6.69 MB

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Abstract

Microbial growth is often described in terms of resource uptake rates, making the understanding and parameterization of these rate-limiting processes critical for microbial modeling. In phototrophic plankton, theoretical studies suggest that nutrient uptake is limited by mechanistic processes involving membrane transporters, and it has been observed that the cell-specific maximum resource uptake rate (Vmax) follows a power-law relationship with cell size, as well as a trade-off between Vmax and the half-saturation constant (Km). These constraints may also apply to chemotrophic microorganisms; however, many datasets lack direct cell-size measurements. We therefore leveraged the assumption that prokaryotic cell sizes, Vmax, and Km each follow log-normal distributions, drawing parallels with established phytoplankton scaling laws. Our analysis suggests that chemotrophic organisms generally exhibit higher maximum uptake rate per dry weight (VmaxDW) and Km values than phototrophs, and that VmaxDW and Km are not strongly correlated when all chemotroph data are combined. Furthermore, the Bayesian-derived exponents for VmaxDW and Km exceeded those expected from allometric scaling relationships based on the membrane-transport capacity observed for phototrophs, implying that a range of additional factors likely affect observed kinetic parameters.