Enzymatic characterization of Chilean native wood-rotting fungi for potential use in the bioremediation of polluted environments with chlorophenols

Abstract

This work presents a preliminary report of a series of studies on the ability of several indigenous wood-rotting fungi from Chile to produce hydrolytic and ligninolytic enzymes and the evaluation of these native microorganism to future research on potential applications in bioremediation programs. Wood-rotting Basidiomycete fungi were collected from indigenous hardwood forest in the South of Chile. Twenty-eight strains were identified and qualitative enzymatic tests for peroxidases, laccase, tyrosinase, xylanase and cellulase production were performed in solid medium. Eleven selected strains were evaluated in liquid medium to quantify their ligninolytic enzyme production and their capacity to grow in solid medium supplemented with 2,4-dichlorophenol (2,4-DCF), 2,4,6-trichlorophenol (2,4,6-TCF) and pentachlorophenol (PCP). PCP degradation and ligninolytic enzymes production were also evaluated in liquid medium. Results showed that laccase was present in 28 of the selected strains (&73%). Peroxidase was present in 40% and cellulase in 37% of the strains. Xilanase and tyrosinase were obtained in a smaller percentage in the strains (28% and 7%, respectively). The 11 selected strains showed high concentrations of lignin peroxidase (Lip) and manganese peroxidase (MnP). Anthracophyllum discolor (Sp4), produced LiP and MnP at 90.3 and MnP 125.5 U L -1 respectively, compared to the control fungus Phanerochaete chrysosporium CECT-2798 that produced 58.1 and 118.4 U L -1 of LiP and MnP. Tolerance test showed that native Chilean fungi did not present high tolerance to 2,4,6-TCF and PCP but were quite tolerant to 25 and 50 mg L -1 of 2,4-DCF. However, pre-acclimatization in 2,4-DCP notably improved the growth in medium with 2,4,6-TCP and PCP. PCP in liquid medium was efficiently degraded by the fungi Anthracophyllum discolor, Lenzites betulina (Ru-30) and Galerina patago´nica (Sp3), and the major MnP activity was produced by A. discolor (Sp4) (67 U L -1 ).

The Role of White-rot Fungi in Herbicide Transformation

“…[11,[56][57][58][59][60][61][62][63][64][65]. This list may be expanded given the strong evidence for WRF degradation potential toward different classes of pollutants.…”

Effect of Soya Lecithin on Solubilization and Biodegradation of Pentachlorophenol by <i>Anthracophyllum discolor</i>

“…The PCP effects on growth of several white-rot fungi have been well studied. In this context, Tortella et al [13] studied the tolerance of fungi to mycelia growth in the presence of PCP. They found inhibition mycelia growth when the fungi were exposed at 25 mg•L −1 of PCP.…”

“…However, Alleman et al [48] detected inhibition of growth with 5 -10 mg•L −1 of PCP for P. chrysosporium, T. versicolor, Inonotus sp, Ganoderma sp. The several responses found could be due to composition of liquid medium and growth conditions [49], PCP doses [44], or fungal strains adapted to PCP [13].…”

“…Several studies have led to finding native fungal strains with ligninolytic activity and capacity to degrade several contaminants. Studies realized by Rubilar et al [6,10] and Tortella et al [13] have demonstrated that Anthracophyllum discolor, a native Chilean fungus, presents the ligninolytic activity with high level of MnP production and capacity to degrade PCP. However, these processes are negatively affected by the low water solubility of the contaminants, limiting their availability to microorganisms.…”

A practical culture technique for enhanced production of manganese peroxidase by Anthracophyllum discolor Sp4

“…Over the past few years, a great deal of attention has been paid to the potential use of MnP in biobleaching of pulp and paper and for xenobiotic compounds degradation because of the characteristics of its catalytic cycle (Eibes et al, 2002;Wariishi et al, 1992). Anthracophyllum discolor Sp4 is a Chilean whiterot fungus isolated from the decayed wood in the rain forest of southern Chile (Tortella et al, 2008). This fungus has a potential for degradation of organic pollutants because of its high production of ligninolytic enzymes, especially MnP (Rabinovich et al, 2003;Rubilar et al, 2007), and can thus be used in bioremediation systems.…”