Consequences of Misnomer or Mistakes in Identification of Fungal Species.

The author, as a reviewer of many international journals, describes his long-standing experiences with incorrect identification of mushroom and fungal species and the resultant incorrect naming of those species that served as experimental models. From his own praxis, he selected several characteristic examples that sometimes ended in a curious situation. Some recommendations to authors of publications and persons responsible for the proper naming of mushrooms under study are summarized.

Breakdown products on metabolic pathway of degradation of benz[a]anthracene by a ligninolytic fungus.

Cultures of the ligninolytic fungus Irpex lacteus incubated in a nutrient liquid medium degraded more than 70% of the initially applied benz[a]anthracene within 14 days. At the first step of metabolization, benz[a]anthracene was transformed via a typical pathway of ligninolytic fungi to benz[a]anthracene-7,12-dione (BaAQ). The product was further transformed by at least two ways, whereas one is complied with the anthracene metabolic pathway of I. lacteus. Benz[a]anthracene-7,12-dione was degraded to 1,2-naphthalenedicarboxylic acid and phthalic acid that was followed with production of 2-hydroxymethyl benzoic acid or monomethyl and dimethylesters of phthalic acid. Another degradation product of BaAQ was identified as 1-tetralone. Its transformation via 1,4-naphthalenedione, 1,4-naphthalenediol and 1,2,3,4-tetrahydro-1-hydroxynaphthalene resulted again in phthalic acid. None of the intermediates were identified as dead-end metabolites. Metabolites produced by ring cleavage of benz[a]anthracene using the ligninolytic fungus are firstly presented in this work.

Application of supercritical fluid extraction (SFE) to predict bioremediation efficacy of long-term composting of PAH-contaminated soil.

Supercritical fluid extraction (SFE) with pure carbon dioxide was used to obtain desorption curves of PAHs from four contaminated industrial soils. Total PAH concentrations ranged from 1495 to 2439 mg/kg. The desorption curves were fitted with a simple two-site model to determine the rapidly released fraction (F) representing bioavailability of PAHs. The Fdata obtained under various SFE pressures were compared with degradation results of a composting method applied on the soils. After composting and consequent long-term maturation, the residual PAH contaminations ranged from 4 to 36% of the original values. A possible explanation of the result variations is the different bioavailability of the pollutants. The best correlations between degradation results and F fraction were obtained applying 50 degrees C and 300 bar. The F values gave very good agreement with degradation efficiencies and the total regression coefficients (r) ranged from 0.81 to 0.99. The degradation results together with bioavailable fractions appeared to be consistentwith organic carbon contents in the soils and with volatile fractions of organics. The results indicate that SFE could be a rapid testto predict bioremediation results of composting of PAH-contaminated soils.

Structure selectivity in degradation and translocation of polychlorinated biphenyls (Delor 103) with a Pleurotus ostreatus (oyster mushroom) culture.

The biodegradation of polychlorinated biphenyls (PCBs), formerly applied in technical mixtures called Delor 103, was realized by the white rot fungus Pleurotus ostreatus. Besides the efficiency of degradation the translocation of PCBs into the fruit bodies grown during cultivation on straw were of special interest. The selectivity of PCBs degradation is discussed on the basis of structural features of the individual congeners. The most important structural factors affecting the degradation efficiency are indicated with molecular descriptors. Basic dependences of the degradation efficiency of congeners on their chlorination grade and ortho chlorosubstitution could be proved. Additionally, other structural parameters such as the number and position of non-substituted carbon in the biphenyl molecule also affect the degradation results. Apart from the removal of Delor 103 the translocation of PCB isomers into the fruit bodies growing up during cultivation was observed. The structural features assisting the transport of PCB congeners from the straw substrate colonized with mushroom mycelium (straw/mycelium) to the mushroom fruit bodies are also relevant for the degradation mechanism but act reversely. Among the chlorination grade, structural parameters such as the number of para and adversely positioned chlorines or the number of occupied para and meta positions contribute to an accumulation of individual PCB congeners in the mushrooms. In total, only few PCB amounts (below 0.1% of the initially present PCBs in straw) were transported into the fruit bodies and a dangerous PCB contamination was never reached while the experiment. A combination of accelerated solvent extraction and GC-MS analysis was the analytical basis for the investigation presented.

Study of fungal degradation products of polycyclic aromatic hydrocarbons using gas chromatography with ion trap mass spectrometry detection.

Representatives of polycyclic aromatic hydrocarbons (PAHs) were degraded by ligninolytic fungus Irpex lacteus. The products were analyzed by GC-Ion trap mass spectrometry. The combination of full scan mass spectra, product ion scans (MS-MS) and derivatization of the degradation products of anthracene, phenanthrene, fluoranthene and pyrene provided further insight in the degradation mechanism initiated by I. lacteus. Particularly, the product ion scans enabled the interpretation of unknown degradation products, even though they were only produced at trace level. Most of the structures suggested were later confirmed with authentic standards.