Wood and humus decay strategies by white-rot basidiomycetes correlate with two different dye decolorization and enzyme secretion patterns on agar plates

Abstract

During several forays for ligninolytic fungi in different Spanish native forests, 35 white-rot basidiomycetes growing on dead wood (16 species from 12 genera) and leaf litter (19 species from 10 genera) were selected for their ability to decolorize two recalcitrant aromatic dyes (Reactive Blue 38 and Reactive Black 5) added to malt extract agar medium. In this study, two dye decolorization patterns were observed and correlated with two ecophysiological groups (wood and humus white-rot basidiomycetes) and three taxonomical groups (orders Polyporales, Hymenochaetales and Agaricales). Depending on the above groups, different decolorization zones were observed on the dye-containing plates, being restricted to the colony area or extending to the surrounding medium, which suggested two different decay strategies. These two strategies were related to the ability to secrete peroxidases and laccases inside (white-rot wood Polyporales, Hymenochaetales and Agaricales) and outside (white-rot humus Agaricales) of the fungal colony, as revealed by enzymatic tests performed directly on the agar plates. Similar oxidoreductases production patterns were observed when fungi were grown in the absence of dyes, although the set of enzyme released was different. All these results suggest that the decolorization patterns observed could be related with the existence of two decay strategies developed by white-rot basidiomycetes adapted to wood and leaf litter decay in the field.

Extracellular Enzymatic Activity of <i>Tuber maculatum</i> and <i>Tuber aestivum</i> Mycelia

“…However, the present study showed the presence of peroxidase activity. Such different peroxidase enzyme secretion patterns have been observed in white rot wood fungi and white rot humus fungi [16]. Tuber maculatum showed the presence of cellulase and laccase activities belonging to the lignocellulolytic group of enzymes as well as xylanase activity.…”

Bioremediation potential of filamentous fungi in methylene blue: Solid and liquid culture media

“…In this present study, it was not possible to quantify the percentage of degradation of the dye in the solid medium, although discoloration of the culture medium was observed with isolates DF39, EF58, FUS, and PS, indicating the degradation of the dye. Barrasa et al (2014) observed that there are two patterns of discoloration of synthetic dyes in solid culture medium. According to these authors, saprophytic white rot fungi, belonging to the order Agaricales, form a brown halo external to the colony due to the increases synthesis of peroxidase enzymes and laccases on the colony edges.…”

“…synthesize specific enzymes on the culture medium (Barrasa et al, 2014;Kanagaraj;Senthilvelan;Panda, 2015). For the P. ostreatus EF60 isolate, the increase in the methylene blue concentration reduced the mycelial diameter at 50 mg L -1 by 38.5%, and the mycelial growth was adjusted to a quadratic regression model.…”

“…However, the bioremediator action of a fungi isolate depends on the dye (Al-Jawhari, 2015) and enzyme-specific synthesis (Barrasa et al, 2014). Media followed by the same lowercase (in the column) and uppercase (in the line) letter did not differ according to Scott-Knott's test at a 5% probability; 2 ns is not significant, * is significant at 1% (p <0.1) and ** is significant at 5% (0.01≤p <0.05).…”

Remoción de colorantes reactivos empleando el hongo Bjerkandera adusta

“…Diferentes estudios muestran la capacidad que tienen los hongos de la pudrición blanca de la madera debido a que poseen un sistema oxidativo que exhibe un alto grado de especificidad, permitiéndoles degradar un amplio número de compuestos recalcitrantes además de la lignina (Anastasi et al, 2010;Barrasa et al, 2014). Actualmente se utilizan sistemas aerobios y anaerobios, con hongos y bacterias para la decoloración y mineralización de los colorantes presentes en dichas aguas (Kumar et al, 2016;Senthilkumar, Perumalsamy y Prabhu, 2014).…”