Metabolic pathways involved in aromatic azo dyes degradation by Trichosporon akiyoshidainum.

MILAGRO ROSALES SORO; LUCÍA I. CASTELLANO DE FIGUEROA; DANIEL GERMÁN KURTH; PAJOT, HIPÓLITO F.; NATALIA BULACIO GIL; CARLOS G. NIETO PEÑALVER

Bariloche

Simposio; 34 International Specialized Symposium on Yeasts; 2018

Centro Regional Universitario Bariloche

Trichosporon akiyoshidainum is basidiomycete yeast that proved to be a promising toolfor biodegradation of textile dyes. The mechanism involved in this process likely involveenzymes like laccases and Mn-peroxidases, and other peroxidases, which activities havebeen detected in culture supernatants of cells grown in the presence of textile azo dyes.However, it is also possible that radical-generating reactions like Fenton-type reactionsare involved in the process. In order to elucidate the metabolic pathways involved inaromatic azo dyes degradation, a genomics analysis was carried out allowing identifyingseveral clusters of genes implicated in different steps of the dye degradation. Througha proteomic analysis, by nanoLC-MS/MS, a complete spectrum of peroxide-producingoxidases, radical-producing enzymes and other relevant compounds involved in ironhomeostasis, iron reduction, and quinone cycle were identified in the presence ofReactive Black 5 (RB5) dye. These results are consistent with the biodegradation of dyeby Fenton or Fenton-mediated reactions in which Fe (II) and H2O2 react to form hydroxylradicals, highly reactive species capable of depolymerizing aromatic compounds. Thoseresults were further verified by biomimetic assays, proving that Fenton-type reactionscould drive dye removal. The degradation of the dye BR5 by T. akiyoshidainumdemonstrated to be a complex process that comprises both enzymatic and nonenzymaticoxidative reactions. Both mechanisms are similar to those involved in thebiodegradation of the lignocellulosic material by filamentous fungi. The elucidation ofthe metabolic pathways linked to the degradation of BR5 is an important contributionto the study of the aerobic degradation of aromatic dyes by yeasts and could berecognized as a starting point in the exploration of the lignocellulolytic potential of T.akiyoshidainum and related yeasts.