Assessing the ability of white-rot fungi to tolerate polychlorinated biphenyls using predictive mycology

Marcela Alejandra Sadañoski,Juan Ernesto Velázquez,María Isabel Fonseca,Pedro Darío Zapata,Laura Noemí Levin,Laura Lidia Villalba

doi:10.1080/21501203.2018.1481152

Abstract

ABSTRACTThe aim of the present study was to assess the ability of different white-rot fungi to tolerate polychlorinated biphenyls (PCBs) using predictive mycology, by relating fungal growth inhibition to ligninolityc enzyme secretion. Fungal strains were grown in the presence of PCBs in solid media and their radial growth values were modelled through the Dantigny-logistic like function in order to estimate the time required by the fungal colonies to attain half their maximum diameter. The principal component analysis (PCA) revealed an inverse correlation between strain tolerance to PCBs and the laccase secretion over time, being laccase production closely associated with fungal growth capacity. Finally, a PCA was run to regroup and split between resistant and sensitive fungi. Simultaneously, a function associated with a model predicting the tolerance to PCBs was developed. Some of the assayed isolates showed a promising capacity to be applied in PCB bioremediation.Abbreviations: Polychlorinated biphenyls (PCBs), white-rot fungi (WRF)

Highlights

Polychlorinated biphenyls (PCBs) are a group of chlorinated organic pollutants that have been used in a wide range of products in the twentieth century
The results obtained in this work endorse predictive mycology as a tool and preliminary step to improve the screening and selection of strains capable of tolerating PCBs
The observed decrease in fungal growth while increasing PCB concentration is in agreement with previous studies (Murado et al 1976). This negative effect of PCBs on fungal growth rate allows assuming that tolerance for PCBs is a reliable indicator of fungal ability to co-metabolise these pollutants (Yin et al 2011). This is the first screening evaluating growth and ligninolytic enzyme production by white-rot fungi (WRF) in a solid medium amended with PCBs, as a strategy to select tolerant fungi to these pollutants

Summary

Introduction

Polychlorinated biphenyls (PCBs) are a group of chlorinated organic pollutants that have been used in a wide range of products in the twentieth century. There are costly physical and chemical options for degradation of PCBs, fungal and bacterial bioremediation proved to be an effective and low-cost strategy for the removal of these pollutants. WRF such as Phanerochaete chrysosporium (Kamei et al 2006a; Čvančarová et al 2012), Phlebia brevispora (Kamei et al 2006b), Coriolus versicolor (Cloete and Celliers 1999; Čvančarová et al 2012), Irpex lacteus, Bjerkandera adusta, Pycnoporus cinnabarinus, Phanerochaete magnolia, Pleurotus ostreatus (Stella et al 2017) and Dichomitus squalens (Čvančarová et al 2012) have already proved their potential for removal of PCBs. WRF possess a ligninolytic enzyme complex comprising, among other enzymes, lignin peroxidase (LiP, EC 1.11.1.14), manganese peroxidase (MnP, EC 1.11.1.13) and laccase (Lac, EC 1.10.3.2), involving as well in the oxidation of a wide range of organopollutants. Other authors documented that these enzymes were involved in PCB bioremediation without establishing their clear role in the removal mechanism (Pointing, 2001; Beaudette et al 1998; Čvančarová et al 2012)

Objectives

Methods

Results

Conclusion