The transformation of biomolecules as catalyzed by mineral colloids plays a vital role in the fromation of humic substances in the environment. The kinds and relative abundance of biomolecules substantially vary with natural vegetation, microbial populations and activity, and the environment. The objective of our study was to examine the effect of the molar ratio of three structurally different polyphenols (catechol, resorcinol or pyrogallol) to Maillard reagents (glucose and glycine) in the integrated polyphenol-Maillard reaction system on carbonate formation and associated humification processes as catalyzed by birnessite (δ-MnO₂). A number of treatments with an increasing concentration of the polyphenols to a fixed molar ratio of the Maillard reagents were conducted at environmentally relevant conditions, i.e., pH 7.0 and 45° C, under sterile conditions.We observed for the first time the biomolecule-induced formation of MnCO₃ (rhodocrosite) as a result of the oxidation and cleavage of glucose, glycine and/or polyphenols by birnessite during the humification processes. The C K-edge NEXAFS and FTIR spectra and XRD data show that the Maillard reaction system had the greatest amount of rhodocrosite formation, and that increasing the molar ratio of polyphenol to Maillard reagents resulted in a decrease in the formation of rhodochrosite in the pyrogallol and catechol systems, while the opposite trend was observed in the resorcinol system. Our results clearly demonstrate that the position and/or number of -OH groups on the benzene ring affects the extent of phenolic ring cleavage and the affinity of the polyphenol to form surface complexes with the birnessite prior to electron transfer. The structure and functionality of polyphenols and molar ratio of polyphenol to Maillard reagents substantially influence rhodocrosite formation and the nature of humic polymers formed. The present findings are of fundamental significance in understanding biomolecule-induced carbonate formation and associated humification in natural environments.