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Quantifying microbial metabolism in soils using calorespirometry - A bioenergetics perspective

Chakrawal, Arjun and Herrmann, Anke and Santruckova, Hana and Manzoni, Stefano (2020). Quantifying microbial metabolism in soils using calorespirometry - A bioenergetics perspective. Soil Biology and Biochemistry. 148 , 107945
[Research article]

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Microbial carbon use efficiency (CUE) measures the partitioning between anabolic and catabolic processes. While most work on CUE has been based on carbon (C) mass flows, the roles of organic C energy contents and microbial energy demand on CUE have been rarely considered. Thus, a bioenergetics perspective could provide new insights on how microorganisms utilize C and ultimately allow evaluating their role in C stabilization in soils. Recently, the calorespirometric ratio (CR)-the ratio of heat dissipation and respiration-has been used to characterize the efficiency of microbial growth in soils. Here, we formulate a coupled mass and energy balance model for microbial growth and provide a generalized relationship between CUE and CR. In the model, we consider two types of organic C in soils: an added substrate (e.g., glucose) and the native soil organic matter (SOM), to also account for priming effects. Furthermore, we consider both aerobic and fermentation metabolic pathways. We use this model as a framework to generalize previous formulations and generate hypotheses on the expected variations in CR as a function of substrate quality, metabolic pathways, and microbial traits (specifically CUE). In turn, the same equations can be used to estimate CUE from measured CR.Our results confirm previous findings on CR and show that without microbial growth, CR depends only on the rates of the different metabolic pathways, while CR is also a function of the growth yields for these metabolic pathways when microbial growth occurs. Under strictly aerobic conditions, CUE increases with increasing CR for substrates with a higher degree of reduction than that of the microbial biomass, while CUE decreases with increasing CR for substrates with a lower degree of reduction than the microbial biomass. When aerobic reactions and fermentation occur simultaneously, the relation between CUE and CR is mediated by (i) the degree of reduction of the substrates, (ii) the rates and growth yields of all metabolic pathways, and (iii) the contribution of SOM priming to microbial growth. Using the proposed framework, calorespirometry can be used to evaluate CUE and the role of different metabolic pathways in soil systems.

Authors/Creators:Chakrawal, Arjun and Herrmann, Anke and Santruckova, Hana and Manzoni, Stefano
Title:Quantifying microbial metabolism in soils using calorespirometry - A bioenergetics perspective
Series Name/Journal:Soil Biology and Biochemistry
Year of publishing :2020
Article number:107945
Number of Pages:21
Publication Type:Research article
Article category:Scientific peer reviewed
Version:Published version
Copyright:Creative Commons: Attribution 4.0
Full Text Status:Public
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Soil Science
Keywords:Bioenergetics, Microbial growth, Calorespirometric ratio, Carbon-use efficiency, Priming effect, Glucose metabolism
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Additional ID:
Type of IDID
Web of Science (WoS)000566668900051
ID Code:17601
Faculty:NJ - Fakulteten för naturresurser och jordbruksvetenskap
Department:(NL, NJ) > Dept. of Soil and Environment
(S) > Dept. of Soil and Environment
Deposited By: SLUpub Connector
Deposited On:25 Sep 2020 11:30
Metadata Last Modified:15 Jan 2021 19:19

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