Publication Details |
| Category | Text Publication |
| Reference Category | Journals |
| DOI | 10.1016/j.soilbio.2026.110146 |
Licence  |
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| Title (Primary) | Theoretical approach to calculate carbon use efficiency of cellulose turnover in soil systems, exemplified at calorespirometric data from artificial soil under various environmental conditions |
| Author | Yang, S.
; Rupp, A.; Kästner, M.; Miltner, A.
; Maskow, T.
|
| Source Titel | Soil Biology & Biochemistry |
| Year | 2026 |
| Department | MIBITECH; MEB |
| Page From | art. 110146 |
| Language | englisch |
| Topic | T7 Bioeconomy |
| Supplements | Supplement 1 |
| Keywords | CUE calculation; EUE; microbial substrate turnover; thermodynamics; respirometry; calorespirometric ratio |
| Abstract | Soil microbial activity drives carbon (C) dynamics through coupled energy fluxes. Carbon use efficiency (CUE) is a common metric which relies on microbial growth fuelled by energy derived from C catabolism for biomass synthesis. Various CUE calculation methods derived from biochemistry and microbial pure culture experiments are available. However, these methods are of limited value for the complex processes in soil because not all products are known or can be measured experimentally. In this study, we evaluated published calorespirometric data on cellulose turnover (Yang et al. 2025) by comparing CUE calculated from thermodynamic enthalpy balances of turnover equations with calorespirometric ratio-based (CR) methods using either degree of reduction (dr) or oxidation state (os). We also compared CUE with energy use efficiency (EUE) derived from net enthalpy changes of the experimental data. Initial CUE and EUE values exceeded 95%, indicating cellulose uptake without immediate mineralization or heat release. Following peak microbial growth (days 28–45), both values declined to 35–50%, which are in the range of published efficiencies. CUE calculations based on mineralization and enthalpy balances of actual substrate consumption, including theoretical biomass formation and N source, closely reflected the experimental net CUE data. In contrast, calculations using the (dr) and (os) approaches yielded overestimated values due to assumptions not valid under soil conditions. These methods apply fixed oxicaloric equivalents or idealized electron transfers, and encounter mathematical discontinuities for certain CR values, resulting in unrealistically high CUE values. Overall, enthalpy balance methods based on real substrate turnover most accurately reflected microbial energy use in calorespirometric soil experiments. Incorporating lower theoretical microbial yields, rather than assuming full stoichiometric conversion to biomass, may further improve the calculations. It is notable that EUE was generally lower than CUE, which indicates that not all of the substrate energy is accessible to microbial metabolism. |
| Yang, S., Rupp, A., Kästner, M., Miltner, A., Maskow, T. (2026): Theoretical approach to calculate carbon use efficiency of cellulose turnover in soil systems, exemplified at calorespirometric data from artificial soil under various environmental conditions Soil Biol. Biochem. , art. 110146 10.1016/j.soilbio.2026.110146 |
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