In vitro degradation of a polymeric dye (Poly R‐478) by manganese peroxidase

Abstract

The aim of this study is the evaluation of the enzymatic action of the ligninolytic enzyme manganese peroxidase (MnP), through a suitable addition of H(2)O(2), as a feasible system for the in vitro degradation of complex structures. For this purpose, a highly recalcitrant polymeric dye (Poly R-478) was selected as a model compound. An amperometric technique was used to determine the H(2)O(2) requirement in the decolorization by nonpurified MnP. Two H(2)O(2) supply strategies-fed-batch (every hour) or semicontinuous (every 5 min)-were applied. The addition of H(2)O(2) in pulses led to a limited decolorization after the pulses and the instantaneous consumption or decomposition of H(2)O(2). Therefore, this way of addition may limit the actual H(2)O(2) concentration in the reaction mixture. In contrast, the semicontinuous strategy maintained lower and prolonged concentrations of H(2)O(2), which allowed a clearly greater decolorization (48% after 2 h). In addition, the effect of Mn(+2) concentration on the decolorization efficiency was investigated to establish the optimal application of the MnP-oxidative system. The enzymatic treatment provoked not only the destruction of the chromophoric groups but also a noticeable breakdown of the chemical structure of the dye. In experiments with pure enzyme, MnP proved to be the main factor responsible for the dye decolorization.

Heterologous Expression of Manganese Peroxidase in Aspergillus niger and Its Effect on Phenanthrene Removal from Soil

“…The intensity of the halo was different among the transformants, SCB2-T3 being the one with the most intense halo. These results are similar to findings by other authors, who screened autochthonous or recombinant fungal strains by the discoloration of Poly R-478 on agar plates and observed halos with different intensities induced by MnP activity [Abdelhafidh et al, 2005;Montiel-González et al, 2009;Moredo et al, 2003;Moreira et al, 2001;Tsukihara et al, 2006].…”

Optimization of a culture medium for ligninolytic enzyme production and synthetic dye decolorization using response surface methodology

“…A disadvantage is the higher costs resulting from the need for extraction and cleaning steps. By contrast, crude culture filtrates offer distinct advantages: they are not as expensive to obtain, and proteins or other factors present in the medium may stabilize crude enzymes, as evidenced by the finding that lower levels of poly R-478 decolorization were obtained with pure MnP of P. chrysosporium than with the nonpurified extracellular liquid [25], and that the highest poly R-478 decolorization rate by crude MnP of P. chrysosporium occurred in parallel with the maximum H 2 O 2 decomposition rate. When H 2 O 2 was depleted, no further decolorization was observed but when H 2 O 2 was supplied semi-continuously, the decolorization rate was much higher [25].…”

Application of Immobilized Pointed Gourd (Trichosanthes dioica) Peroxidase-Concanavalin A Complex on Calcium Alginate Pectin Gel in Decolorization of Synthetic Dyes Using Batch Processes and Continuous Two Reactor System

“…A significant loss of color appeared when DR19 or mixture of dyes was treated with entrapped PGP-Con A complex in the presence of redox mediator, riboflavin in a continuous reactor system (Table 4). It has earlier been reported that the disappearance of peak in visible region was either due to the breakdown of chromophoric groups present in dyes or the removal of pollutants in the form of insoluble products [22].…”