Spent oyster mushroom substrate performs better than many mushroom mycelia in removing the biocide pentachlorophenol

Chlorophenols have been commonly used as disinfectants and preservatives but their recalcitrant nature, persistence and toxicities make them priority pollutants for treatment. The ability of various fungi (Armillaria gallica, A. mellea, Ganoderma lucidum, Lentinula edodes, Phanerochaete chrysosporium, Pleurotus pulmonarius, a Polyporus sp., Coprinus cinereus and Volvariella volvacea), and the spent mushroom substrate of P. pulmonarius (SMS) to remove pentachlorophenol (PCP) was compared using a batch cultivation system. The PCP content was monitored by reversed phase HPLC, and the breakdown products were determined by GC-MS. Possession of ligninolytic ability was determined by ability to decolourize the dye Poly-R478 at two N levels. Not all the fungi tested decolourized the dye, and for those that did, not all showed N-modulation response on dye decolourization. All these fungi showed active breakdown in addition to biosorption as their PCP removal mechanisms. The tolerance level of the fungus towards PCP did not correlate with its degradative capacity, nor to its ability to decolourize Poly-R478. The A. mellea strain showed the highest degradative capacity (13 mg PCP g(-1) mycelium; D.W.) while the Polyporus possessed the greatest biosorption capacity (31 mg PCP gl mycelium, D.W.). In comparison, Pleurotus SMS harbouring both bacteria and fungi functioned over a wide range of initial PCP concentrations and reached a higher degradative capacity (19 mg PCP g(-1)) in only 3 d. GC-MS chromatograms revealed only residual PCP peaks in SMS extracts, a contrast with the mycelial incubations in which a variety of breakdown products were detectable. Use of SMS for bioremediation of biocide-contaminated sites seems promising.