title: A molecular zoom into soil Humeome by a direct sequential chemical fractionation of soil.
abstract: A Humeomics sequential chemical fractionation coupled to advanced analytical identification was applied directly to soil for the first time. Humeomics extracted ~235% more soil organic carbon (SOC) than by the total alkaline extraction traditionally employed to solubilise soil humic molecules (soil Humeome). Seven fractions of either hydro- or organo-soluble components and a final unextractable humic residue were separated from soil. These materials enabled an unprecedented structural identification of solubilised heterogeneous humic molecules by combining NMR, GC-MS, and ESI-Orbitrap-MS. Identified molecules and their relative abundance were used to build up structure-based van Krevelen plots to show the specific contribution of each fraction to SOC. The stepwise isolation of mostly hydrophobic and unsaturated molecules of progressive structural complexity suggests that humic suprastructures in soil are arranged in multi-molecular layers. These comprised molecules either hydrophobically adsorbed on soil aluminosilicate surfaces in less stable fractions, or covalently bound in amorphous organo-iron complexes in more recalcitrant fractions. Moreover, most lipid molecules of the soil Humeome appeared to derive from plant polyesters rather than bacterial metabolism. An advanced understanding of soil humic molecular composition by Humeomics may enable control of the bio-organic dynamics and reactivity in soil.
authors.affiliation: Centro Interdipartimentale di Ricerca sulla Risonanza Magnetica Nucleare per l'Ambiente, l'Agroalimentare ed i Nuovi Materiali (CERMANU), Università di Napoli "Federico II", via Università 100, 80055 Portici, Italy. Electronic address: drosos.marios@gmail.com.
authors.forename: Marios
authors.initials: M
authors.lastname: Drosos
authors.affiliation: Centro Interdipartimentale di Ricerca sulla Risonanza Magnetica Nucleare per l'Ambiente, l'Agroalimentare ed i Nuovi Materiali (CERMANU), Università di Napoli "Federico II", via Università 100, 80055 Portici, Italy. Electronic address: antonio.nebbioso@unina.it.
authors.forename: Antonio
authors.initials: A
authors.lastname: Nebbioso
authors.affiliation: Centro Interdipartimentale di Ricerca sulla Risonanza Magnetica Nucleare per l'Ambiente, l'Agroalimentare ed i Nuovi Materiali (CERMANU), Università di Napoli "Federico II", via Università 100, 80055 Portici, Italy. Electronic address: pierluigi.mazzei@unina.it.
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Mazzei
authors.affiliation: Centro Interdipartimentale di Ricerca sulla Risonanza Magnetica Nucleare per l'Ambiente, l'Agroalimentare ed i Nuovi Materiali (CERMANU), Università di Napoli "Federico II", via Università 100, 80055 Portici, Italy. Electronic address: giovanni.vinci@unina.it.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Vinci
authors.affiliation: Centro Interdipartimentale di Ricerca sulla Risonanza Magnetica Nucleare per l'Ambiente, l'Agroalimentare ed i Nuovi Materiali (CERMANU), Università di Napoli "Federico II", via Università 100, 80055 Portici, Italy. Electronic address: riccardo.spaccini@unina.it.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Spaccini
authors.affiliation: Centro Interdipartimentale di Ricerca sulla Risonanza Magnetica Nucleare per l'Ambiente, l'Agroalimentare ed i Nuovi Materiali (CERMANU), Università di Napoli "Federico II", via Università 100, 80055 Portici, Italy. Electronic address: alessandro.piccolo@unina.it.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Piccolo
keywords: Carbon stabilization; Humeomics; Humic molecules; Organomineral complexes; SOM; Structural identification