Effect of light on birnessite catalysis of the Maillard reaction and its implication in humification

Abstract

Jokic, A., Frenkel, A. I. and Huang, P. M. 2001. Effect of light on birnessite catalysis of the Maillard reaction and its implication in humification. Can. J. Soil Sci. 81: 277-283. The Maillard reaction between carbohydrates and nitrogenous compounds originally investigated in 1912 has subsequently been proposed as a possible pathway for the formation of humic substances in natural environments. However, the role of mineral catalysis of the Maillard reaction is little understood and the promoting effect of light on such catalysis is not known. Birnessite (δ-MnO 2 ), which is commonly present in soil environments, was investigated for its activity in promoting the Maillard reaction between glucose and glycine at a light intensity of 168 µE s -1 m -2 or in the dark. The presence of substantial quantities of Mn(II) was detected in both the supernatant and solid phase of the glucose-glycine-birnessite systems. The spectroscopic evidence indicates that birnessite, in the presence of light, is a very effective catalyst in abiotic browning of solutions of glucose and glycine. Furthermore, birnessite significantly promoted the reaction even in the absence of light. Therefore, the abiotic heterogeneous catalytic role of soil minerals such as birnessite in polycondensation of simple sugars and amino acids merits close attention in the formation of humic substances in natural environments. 'aucuns ont suggéré que la réaction de Maillard entre les glucides et les composés azotés pourrait expliquer la formation des substances humiques en milieu naturel. Toutefois, on sait peu de choses sur le rôle catalytique des minéraux dans cette réaction et on ignore si la lumière favorise la catalyse. Les auteurs ont examiné comment la birnessite (δ-MnO 2 ), qu'on trouve couramment dans le sol, facilite la réaction de Maillard entre le glucose et la glycine à une intensité lumineuse de 168 µE s -1 m -2 ou dans l'obscurité. Ils ont décelé une quantité appréciable de Mn(II) dans le surnageant et dans la phase solide des systèmes glucose-glycine-birnessite. Les données spectroscopiques indiquent qu'en présence de lumière, la birnessite catalyse efficacement le brunissement abiotique des solutions de glucose et de glycine. Par ailleurs, la birnessite facilite sensiblement cette réaction, même dans l'obscurité. Le rôle de catalyseur abiotique hétérogène des minéraux comme la birnessite dans la polycondensation des sucres simples et des acides aminés mérite donc d'être examiné de plus près dans le contexte de la formation des substances humiques en milieu naturel.

Adsorption Mechanism of Ciprofloxacin from Water by Synthesized Birnessite

“…Because of MnO 6 octahedral, the FTIR spectra of original and CIP-absorbed birnessite had a strong absorption peak at about 520 cm −1 . A broad weak and a strong broad peaks appeared in 1624 and 3431 cm −1 with the former attributed to less ordered water and the latter to OH, H 2 O adsorbed on birnessite [26]. The other explanation of these phenomena was the bending mode of H 2 O and the stretching mode of the OH groups.…”

Sorption and desorption of tetracycline on layered manganese dioxide birnessite

“…For raw birnessite, a broad weak peak and a broad strong peak were located at 1,624 and 3,431 cm -1 with the former assigned to less ordered water and the latter to -OH, H 2 O adsorbed on birnessite (Jokic et al 2001). Separately, the broad band at 3,280-3,400 cm -1 was assigned to the stretching mode of OH groups, while the band at 1,610 cm -1 was assigned to the bending mode of H 2 O (White et al 2009).…”

Formation Mechanisms of Humic Substances in the Environment

“…This reaction is kinetically sluggish under ambient temperatures (Jokic et al, 2001c ), but the presence of birnessite signifi cantly catalyzes the reaction by decreasing the activation energy required. Jokic et al (2001a) investigated the effect of light on birnessite catalysis of the Maillard reaction, and they showed that the reaction is promoted by light but also readily occurs in the absence of light. This means that the reaction could readily occur in the subsoil in the presence of a mineral catalyst such as birnessite.…”