Degradation of ¯uorene, anthracene, phenanthrene, ¯uoranthene, and pyrene lacks connection to the production of extracellular enzymes by Pleurotus ostreatus and Bjerkandera adusta
Andres Schutzendubel, Andrzej Majcherczyk*, Christian Johannes, Aloys Huttermann È È È
Institute of Forest Botany, University of Go Èttingen,BuÈsgenweg 2, 37077 Go Èttingen, Germany Received 24 July 1998; received in revised form 6 January 1999; accepted 11 January 1999
Abstract The degradation of polycyclic aromatic hydrocarbons (PAH) was studied in liquid cultures of Bjerkandera adusta and Pleurotus ostreatus during 7 weeks of cultivation. During only 3 days of incubation, B. adusta removed 56% and 38% of ¯uorene and anthracene, while P.ostreatus degraded 43% and 60% of these compounds; other PAH were degraded to a lower extent. Except for anthracene in cultures of P. ostreatus, all PAH were removed uniformly during the cultivation time but ¯uorene and anthracene were degraded faster than other PAH. Supplementation of liquid cultures with milled wood decreased the concentration of PAH in the solution and diminished the degradationof PAH. The fungi produced valuable activity of manganese-dependent peroxidase; laccase was secreted only by P. ostreatus and was strongly induced by the addition of milled wood. The production of the oxidative enzymes did not correlate directly to the metabolisation of PAH. # 1999 Elsevier Science Ltd. All rights reserved.
1. Introduction Most polycyclic aromatic hydrocarbons (PAH),especially the highly condensed compounds with 4 or more rings and their metabolites, have a variety of mutagenic and carcinogenic eects on microorganisms, plants and animals, and are classi®ed as compounds with signi®cant human health risk (Kalf et al., 1997). A widespread contamination of the environment with PAH results from an incomplete combustion of various fossil fuels and organic wastes. Theinertness of these compounds, their low water solubility and strong lipophilic character lead to very high accumulation levels in the environment (e.g. see review by Edwards, 1983). Severe contamination of soil and ground water results mostly from accidental leakage, careless handling, or disposal of coal tar distillation products. The
* Corresponding author. Tel.: +00-49-551-39-94-82; fax:+00-49551-39-27-05. E-mail address: email@example.com (A. Majcherczyk)
microbial breakdown of many creosote-like components was described as early as 1928 by Gray and Thornton (1928). Many subsequent studies on the biodegradation of PAH (e.g. Drisko and O'Neill, 1966; Kerner-Gang, 1975) have paved the way for further studies on the biological disposal of these compounds. Since then, many reports utilisingadapted or isolated bacteria or lower fungi to degrade various, generally low-condensed PAH, have been presented (see reviews by Cerniglia, 1992; Wilson and Jones, 1993). White rot fungi secreting enzymes capable of oxidising aromatic compounds have been shown to be particularly eective in degrading PAH and other xenobiotic compounds (see reviews by Higson, 1991; Paszczynski and Crawford, 1995).Among the enzymes secreted by white rots during degradation of lignin, lignin peroxidase (LiP) and manganese-dependent peroxidase (MnP) were acknowledged to be especially signi®cant in the degradation of PAH (Bumpus et al., 1985; Sanglard et al., 1986; Hammel et al., 1986). However, the degradation of PAH in cultures of fungi without
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A. Schu Ètzendu Èbel et al. / International Biodeterioraton & Biodegradation 43 (1999) 93±100
detected activities of LiP and MnP was also reported (Morgan et al., 1991; Sutherland et al., 1991; Dhawale et al., 1992; Bezalel et al., 1996a). The involvement of laccase secreted by many white rot fungi in the...