Incorporation of hydrogen from ambient water into the C-bonded H pool during litter decomposition

Kessler, Arnim; Kreis, Katharina; Merseburger, Stefan; Wilcke, Wolfgang; Oelmann, Yvonne

doi:10.1016/j.soilbio.2021.108407

Cited by 2 publications

(2 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Section: Methodsmentioning

confidence: 99%

“…To determine δ 2 H values in bacterial biomass, which requires the elimination of the contribution of exchangeable H to δ 2 H t (i) and to quantify the incorporation of ambient-water H into bacterial biomass (ii), we used isotope labeling. 34 We accounted for the exchangeable O-, N-and S-bonded H in the bacterial species (i) with a mass balance approach adopted from Ruppenthal et al 6 The total H (H t ) pool consists of an H ex fraction that isotopically exchanges with water vapor and a Cbonded H fraction (H n ) with respective δ 2 H ex and δ 2 H n values. Total δ 2 H values (δ 2 H t ) could be measured directly, and this pool can be described by eq 2.…”

Section: Bacterial Cultures and Medium Preparationmentioning

confidence: 99%

See 1 more Smart Citation

Incorporation of Ambient Water-H into the C-Bonded H Pool of Bacteria during Substrate-Specific Metabolism

Kessler

Merseburger

Kappler

et al. 2022

ACS Earth Space Chem.

Self Cite

View full text Add to dashboard Cite

The stable isotope ratios of C-bonded H (δ2Hn values) can be used to locate soil samples for forensic purposes because of their close correlation with the δ2H values of precipitation. Post-sampling bacterial activity might change the δ2Hn values via glycolysis. We tested to which degree C-bonded H is replaced by H from ambient water under favorable and unfavorable growing conditions. We provided two heterotrophic bacteria (Bacillus atrophaeus, Escherichia coli) with glucose (favorable) or lysine (unfavorable) under aerobic conditions. We assessed the H incorporation from ambient water via 2H labeling. We found that the H incorporation into bacterial biomass in the glucose treatment was 79 ± 5.9% (B. atrophaeus) and 43 ± 3.0% (E. coli), likely as a consequence of glycolysis and conservation of the δ2H value in the anabolic mode of the tricarboxylic acid (TCA) cycle. Differences between species were possibly related with different compositions of metabolite mixtures. The bacteria did hardly grow with lysine while respiration continued, and we found no H incorporation because the catabolic mode of the TCA cycle, which was active when the bacteria grew on lysine, is associated with CO2 release and a complete cleavage of former C–2H bonds. Our results support the glycolysis pathway as a mechanism underlying the incorporation of ambient-water H into the C-bonded H pool of bacteria. Stressful conditions forcing bacteria into a catabolism-dominated metabolism disable the incorporation of ambient-water H, and δ2Hn values can be applied to identify the origin of soil samples in forensics.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Bacterial Cultures and Medium Preparationmentioning

confidence: 99%