Impacts of holmium and lithium to the growth of selected basidiomycetous fungi and their ability to degrade textile dyes.

The impacts of Ho and Li (0, 10, 50, 200 mg/L) were tested towards the growth of four basidiomycetous fungal species, their ability to decolorise synthetic dyes (Reactive Green 19, Reactive Orange 16, Reactive Black 5), and produce oxidative enzymes. All species; Agrocybe dura, Skeletocutis biguttulata, Exidia saccharina and Galerina paludosa; grew with and without supplemented Ho or Li. The growth of S. biguttulata was the most tolerant species towards Ho or Li (200 mg/L), whereas the growth of G. paludosa was the most sensitive of the studied species to both 200 mg Ho or Li/L. All fungi oxidized ABTS [2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)] forming colour zone on plate tests indicating production of lignin modifying laccase enzyme. A. dura and G. paludosa, formed black MnO2 zone in Mn2+ plates, which indicates the production of manganese peroxidase (MnP). A. dura and G. paludosa decolorised Reactive Black 5 indicating the production of versatile peroxide (VP) enzyme. Our study presents two new candidate species able to produce VP. A. dura was capable of decolorising all tested synthetic dyes in the presence of Ho or Li (0-200 mg/L) suggesting that this fungus is a promising species for bioremediation of multi dye-containing wastes. © King Abdulaziz City for Science and Technology 2020.