Synthesis of ¹³C‐labelled cutin and suberin monomeric dicarboxylic acids of the general formula HO₂¹³C‐(CH₂)_n‐¹³CO₂H (n = 10, 12, 14, 16, 18, 20, 22, 24, 26, 28)

Abstract

13C‐labeled dicarboxylic acids HO213C‐(CH2)n‐13CO2H (n = 10, 12, 14, 16, 18, 20, 22, 24, 26, 28) have been synthesized as internal standards for LC‐MS and GC‐MS analysis of cutin and suberin monomer degradation by soil‐based microorganisms. Different synthetic strategies had to be applied depending on the chain length of the respective synthetic target and because of economic considerations. 13C‐labels were introduced by nucleophilic substitution of a suitable leaving group with labelled potassium cyanide and subsequent hydrolysis of the nitriles to produce the corresponding dicarboxylic acids. All new compounds are characterized by GC/MS, IR, and NMR methods as well as by elemental analysis.

Size matters: biochemical mineralization and microbial incorporation of dicarboxylic acids in soil

“…Four position specifically 13 C labeled isotopomers of DCA with different chain lengths were used as tracer compounds, and two non-labeled DCA served as natural background substances. A total of 72 microcosms (6 DCA treatments × 4 replicates × 3 sampling dates) were prepared.…”

“…To produce the applied DCA, a novel synthetic protocol based on chain elongation of various precursors followed by a terminal 13 C introduction using K 13 CN and subsequent hydrolysis to produce the respective DCA was designed (Schink et al 2020).…”

“…The contribution of fungi to carboxylic acid-C utilization was less than that of bacteria, due to their lower competitiveness for water soluble substances (Gunina et al 2014;Waldrop and Firestone 2004). To unravel the fate and transformation/incorporation of DCA-C by specific microbial groups, we established an incubation experiment using position-specifically labeled D 13 CA. Position-specific labeling is a tool that has recently reached an increasing consideration in soil science (Fischer and Kuzyakov 2010;Dijkstra et al 2011;Apostel et al 2013;Dippold and Kuzyakov 2013).…”

“…It overcomes the limitations of uniform labeling because it allows differentiation between the incorporation of molecule fragments vs. the incorporation of entire intact molecules (Apostel et al 2015). PLFA analysis allows the reconstruction of the microbial community composition (Zelles et al 1995;Zelles 1999), but in combination with 13 C labelingi.e. 13 C-PLFA analysis -it enables the tracing of substrate incorporation into microbial cell membranes and therefore the reconstruction of individual microbial groups (Glaser 2005).…”

“…PLFA analysis allows the reconstruction of the microbial community composition (Zelles et al 1995;Zelles 1999), but in combination with 13 C labelingi.e. 13 C-PLFA analysis -it enables the tracing of substrate incorporation into microbial cell membranes and therefore the reconstruction of individual microbial groups (Glaser 2005). We selected four carboxylic group enriched fatty diacids as monomers, which we expected to be quite abundant in soils since they have either been derived from microbial synthesis or suberin decomposition (Banfield et al 2018).…”