Volatile constituents of wood-rotting basidiomycetes

Phytochemical investigation of the hydrodistillation products of the basidiomycetes Fomitopsis pinicola, Piptoporus betulinus, Gloeophyllum odoratum and Trametes suaveolens led to the identification of numerous mono- and sesquiterpenes as well as many aliphatic alcohols, aldehydes and ketones and some aromatic compounds. In addition, some diterpenes were identified as constituents of Fomitopsis pinicola. The absolute configuration of some terpenes was determined     

Constituents of various wood-rotting basidiomycetes

Phytochemical investigation of n-hexane and methanol extracts of fruiting bodies of the wood-rotting fungi Fomitopsis pinicola. Ganoderma lipsiense, Fomes fomentarius and Gloeophyllum odoratum led to the isolation and identification of several triterpene derivatives and some aromatic compounds derived from lignin. These are the new natural products, namely, pinicolic acid E (16alpha-hydroxy-3-oxolanosta-8,24-dien-21-oic acid) and pinicolol C (3-oxolanosta-7,9(11),24-trien-15alpha,21-diol) from the crust of F. pinicola, ganoderenic acid D [(E)-7beta-hydroxy-3,11,15,23-tetraoxolanosta-8,20(22)-di en-26-oic acid] and ganoderic acid N (7beta,20-dihydroxy-3,11,15,23-tetraoxolanost-8-en-26-oic acid) from G. lipsiense and ergosterol peroxide (5alpha,8alpha-epi-dioxyergost-6-en-3beta-ol) as well as ergost-7-en-3-one from F. fomentarius. From G. odoratum, dehydroeburicoic acid [24-methylene-3-oxolanosta-7,9(11)-dien-21-oic acid], the dimethylacetal of 4,4,14alpha-trimethyl-24-oxo-5alpha-chol-8-en-21-oic acid and some aromatic compounds, of which 1-(4'-methoxyphenyl)-1,2-ethandiol is a new natural product, were isolated. Furthermore, a complete set of 13C NMR data of the steryl esters 3beta-linoleyloxyergosta-7,24(28)-diene, 3beta-linoleyloxyergosta-7,24-diene and 3beta-linoleyloxyergost-7-ene, which could be identified as a mixture in all investigated fungi, could be recorded. It was proved by HPLC and TLC investigations, that the crust on top of the fruiting bodies of F. pinicola consists of lanostane derivatives.     

A selective medium for the isolation of wood-rotting basidiomycetes

A selective medium for growing wood-rotting basidiomycetes is described. The medium is based on a mixture of benomyl and 2-phenylphenol which suppresses the growth of lower fungi and Sistotrema brinkmannii, a basidiomycete of frequent occurrence in timber but one which cannot decay wood. Use of the medium in isolation studies permits a higher recovery of wood-rotting basidiomycete fungi than can be achieved by the use of other selective media.     

Screening of Brazilian basidiomycetes for antimicrobial activity

A total of 103 isolates of basidiomycetes, representing 84 species from different Brazilian ecosystems, were evaluated for their antifungal and antibacterial activity in a panel of pathogenic and non-pathogenic microorganisms. Tissue plugs of the fruiting bodies were cultivated in liquid media and the whole culture extracted with ethyl acetate. Crude extracts from Agaricus cf. nigrecentulus, Agrocybe perfecta, Climacodon pulcherrimus, Gloeoporus thelephoroides, Hexagonia hydnoides, Irpex lacteus, Leucoagaricus cf. cinereus, Marasmius cf. bellus, Marasmius sp., Nothopanus hygrophanus, Oudemansiella canarii, Pycnoporus sanguineus, Phellinus sp., and Tyromyces duracinus presented significant activity against one or more of the target microorganisms. Eight isolates were active only against bacteria while three inhibited exclusively the growth of fungi. Two extracts presented wide antimicrobial spectrum and were active against both fungi and bacteria. Differences in the bioactivity of extracts obtained from isolates from the same species were observed.     

Isolation and characterization of psychrophilic yeasts producing cold-adapted pectinolytic enzymes

AIMS: The present study was conducted to screen for psychrophilic yeasts that are able to degrade pectin compounds at low temperature, and to examine the cold-active pectinolytic enzymes produced by the isolated psychrophilic yeasts. METHODS AND RESULTS: Psychrophilic yeasts, which grow on pectin as a sole carbon source, pectinolytic-psychrophilic yeast (PPY) strains PPY-3, 4, 5 and 6, were isolated from soil from Abashiri (Hokkaido, Japan). The sequences of 28S rDNA D1/D2 of strains PPY-3 and 4 indicated a taxonomic affiliation to Cryptococcus cylindricus and Mrakia frigida, respectively, strains PPY-5 and 6 belonged to Cystofilobasidium capitatum. The isolated strains were able to grow on pectin at below 5 degrees C, and showed the activities of several cold-active pectinolytic enzymes. CONCLUSION: The findings of this study indicate the possibility that the isolated strains produce novel pectinolytic enzymes that are able to degrade pectin compounds at low temperature. Significance and Impact of the Study: It is possible that the cold-active pectinolytic enzymes from the isolated strains can be applied to the food industry, e.g. the clarification of fruit juice below 5 degrees C.     

Copper sorption by native and modified pellets of wood-rotting basidiomycetes

AIMS: The aim of this study was to investigate the biosorption of copper to the pellets of different wood-rotting fungal species. METHODS AND RESULTS: Copper sorption was studied in both batch and column arrangements. The optimum pH for copper sorption was between 3.5 and 4. In 100 mg l(-1) Cu (II), maximum qe values were found for Oudemansiella mucida (8.77 mg g(-1) dry wt), Lepista nuda (6.29 mg g(-1)), Pycnoporus cinnabarinus (5.08 mg g(-1)) and Pleurotus ostreatus (4.77 mg g(-1)). Both biomass yield and specific sorption were influenced by the composition of the fermentation broth. The results of column experiments showed that mycelial pellets of wood-rotting fungi can be considered as promising biosorbent material. CONCLUSIONS: Pellets of wood-rotting fungi showed the same or better copper sorption properties as those previously reported for lower fungi or filamentous bacteria, as well as good mechanical properties.     

Effect of heavy metals on the growth of selected wood-rotting basidiomycetes

Mercury, cadmium and cobalt were found to be the most toxic heavy metals, inducing strong growth inhibition of the tested basidiomycetes. The studied species differed significantly in their sensitivity to cadmium. The most sensitive fungus,Inonotus obliquus, did not grow at Cd concentrations higher than 0.1 mmol/L, whereasStereum hirsutum grew at more than 2 mmol Cd/L. Changes in mycelial morphology were observed inS. hirsutum andTrametes versicolor cultivated in the presence of cadmium and mercury. The toxicity of heavy metals was lower in rich, complex media. Presented at the 4th Mini-Symposium on Biosorption and Microbial Degradation, Prague, Czech Republic, November 26–29, 1996.     

Screening of basidiomycetes for antimicrobial activities

As a part of a screening programme developed to evaluate the antimicrobial activity of basidiomycetes, 317 isolates representing 204 species collected in Spain were screened against a range of human clinical pathogens and laboratory controls. Extracts from 45% of the isolates, representing 109 species, showed antimicrobial activity. Antibacterial activity was more pronounced than antifungal activity. The proportion of extracts from basidiomycetes showing antimicrobial activity was similar to or above that obtained for representative orders of Ascomycetes, such as Pezizales and Xylariales, but lower than that produced by members of the orders Diaporthales, Eurotiales, Hypocreales, Leotiales and Sordariales. Suprageneric taxa (orders and families) did not show pronounced differences in their antimicrobial activities though such differences were observed at the genus level, suggesting that the ability to produce these bioactive compounds is not homogenously distributed amongst the basidiomycetes. Isolates from some species showed large differences in their ability to produce metabolites with antimicrobial activity, possibly reflecting genetic differences at the infraspecific level.     

Screening for decolorizing basidiomycetes in Mexico

A survey to isolate native white rot basidiomycetes from Northeast Mexico was conducted in the forests of the Sierra Madre Oriental in the state of Nuevo León. A total of 92 isolates from at least 20 different genera, were screened on Bran-Flakes solid plate cultures for the production of ligninolytic oxidases and/or peroxidases with guaiacol and o-anisidine as substrates; their lignin depolymerizing potential using the polymeric dye Poly R 478; their ability to decolorize anthraquinonic (Remazol Brilliant Blue Reactive), azo (Acid Red 44) and triphenylmethane (Crystal Violet) dyes. Among all fungi tested, 15 isolates showed extensive decolorization of the three dyes within a week and gave a positive reaction in guaiacol and o-anisidine tests. Nine of them were also efficient degraders of Poly R-478. Two isolates (CS5 and CU1) showed decolorization of all dyes within 5 days, comparing favorably with reference strains of P. chrysosporium, Pleurotus ostreatus, and Bjerkandera adusta. Decolorization was associated with laccase activity in both isolates and reached 90% or more for all dyes within 24 h in 8-day-old liquid cultures. The coupling of pairs 2,4-dichlorophenol + 4-aminoantipyrine and 3-dimethylaminobenzoic acid + 3-methyl-2-benzothiazolinone hydrazone, strongly suggest that the laccases of both strains correspond to those considered of high redox potential. These strains are considered good candidates for bioremediation of dye polluted effluents due to their ligninolytic potential and decolorizing performance.     

Sulphur oxidation by soil fungi including some species of mycorrhizae and wood-rotting basidiomycetes

Abstract The mycorrhizal fungi Amanita muscaria, Paxillus involutus, Hymenoscyphus ericae, Pisolithus tinctorius, Rhizopogon roseolus , and Suillus bovinus oxidized elemental sulphur to thiosulphate and sulphate in vitro. In some, but not all cases, tetrathionate was also formed. Limited oxidation of elemental sulphur by R. roseolus also occurred when growing in association with Pinus contorta in unsterilized peat. Although yeasts capable of oxidizing sulphur could not be isolated from a wide range of soils, a yeast-like fungus ( Monilia sp.) isolated from deciduous woodland soil oxidized elemental sulphur to sulphate, forming thiosulphate, but not tetrathionate. This fungus also oxidized tetrathionate to sulphate but showed only limited ability to oxidize thiosulphate to tetrathionate. Both Aspergillus niger and Trichoderma harzianum oxidized elemental sulphur in mixed culture with Mucor flavus . Larger amounts of sulphate were initially formed in mixed, compared to single culture; but by week 5 of the incubation period sulphate formation was greatest in single culture. The wood-rotting fungi, Hypholoma fasciculare and Phanerochaete velutina showed a limited ability to oxidize elemental sulphur in vitro but were incapable of oxidizing the element when growing as mycelial cords in non-sterilized soils. The relevance of these results to the possibility that fungi play a role in sulphur oxidation in soils is commented upon.     

A note on the pectinolytic enzymes of Lachnospira multiparus

The identification of pectinolytic enzymes from two strains of Lachnospira multiparus grown on media containing pectin with differing degrees of methylation as the carbon source was investigated. Both pectinesterase and lyase activity were determined but there was no evidence of polygalacturonase being present as either an extracellular or intracellular enzyme.     

A proposed role of oxalic acid in wood decay systems of wood-rotting basidiomycetes

Abstract: The possible roles of oxalic acid, veratryl alcohol, and manganese were investigated in relation to lignin biodegradation by white-rot basidiomycetes. Oxalate inhibited both lignin peroxidase (LiP) and manganese-peroxidase (MnP). and was decarboxylated by the mediation of veratryl alcohol and Mn. Oxalate was shown to regulate the mineralization of lignin in the in vivo system of Phanerochaete chrysosporium . In the brown-rot wood decay process, oxalic acid may serve as an acid catalyst as well as an electron donor for the Fenton reaction, to breakdown cellulose and hemicellulose. Oxaloacetase and glyoxylate oxidase may play a key role in production of oxalic acid by white-rot and brown-rot basidiomycetes such as Phanerochaete chrysosporium, Coriolus versicolor and Tyromyces palustris . A possible role of oxalate metabolism is discussed in relation to the physiology of wood-rotting fungi.     

Production,partial purification and characterization of ligninolytic enzymes from selected basidiomycetes mushroom fungi

In recent years, many research on the quantity of lignocellulosic waste have been developed. The production, partial purification, and characterisation of ligninolytic enzymes from various fungi are described in this work. On the 21st day of incubation in Potato Dextrose (PD) broth, Hypsizygus ulmarius developed the most laccase (14.83 × 10⁻⁶ IU/ml) and manganese peroxidase (24.11 × 10⁻⁶ IU/ml), while Pleurotus florida produced the most lignin peroxidase (19.56 × ⁻⁶ IU/ml). Laccase (Lac), lignin peroxidase (LiP), and manganese peroxidase (MnP), all generated by selected basidiomycetes mushroom fungi, were largely isolated using ammonium sulphate precipitation followed by dialysis. Laccase, lignin peroxidase, and manganese peroxidase purification findings indicated 1.83, 2.13, and 1.77 fold purity enhancements, respectively. Specific activity of purified laccase enzyme preparations ranged from 305.80 to 376.85 IU/mg, purified lignin peroxidase from 258.51 to 336.95 IU/mg, and purified manganese peroxidase from 253.45 to 529.34 IU/mg. H. ulmarius laccase (376.85 IU/mg) with 1.83 fold purification had the highest specific activity of all the ligninolytic enzymes studied, followed by 2.13 fold purification in lignin peroxidase (350.57 IU/mg) and manganese peroxidase (529.34 IU/mg) with 1.77-fold purification. Three notable bands with molecular weights ranging from 43 to 68 kDa and a single prominent band with a molecular weight of 97.4 kDa were identified on a Native PAGE gel from mycelial proteins of selected mushroom fungus. The SDS PAGE profiles of the mycelial proteins from the selected mushroom fungus were similar to the native PAGE. All three partially purified ligninolytic isozymes display three bands in native gel electrophoresis, with only one prominent band in enzyme activity staining. The 43 kDa, 55 kDa, and 68 kDa protein bands correspond to laccase, lignin peroxidase, and manganese peroxidase, respectively.     

Production of milk-clotting enzymes by basidiomycetes

BasidiomycetesPhellinus chrysoloma, Kuehneromyces mutabilis andGanoderma applanatum produce extracellular milk-clotting enzymes. The enzymes are acid proteinases stable at 40°C and within pH 3–5.5. Only the enzyme preparation fromP. chrysoloma exhibits properties comparable with animal chymosin.     

Screening for dioxin-degrading basidiomycetes from temperate and tropical forests

A total of 500 strains of basidiomycetes isolated from temperate forests in Japan and 379 strains from tropical forests in Indonesia were subjected to a laboratory screening for dioxin-degrading ability. At first, about 200 fungal strains were selected by their ability to decolorize Remazol Brilliant Blue R dye as an indicator of ligninolytic activities. Next, for excluding the factor of dioxin sorption by mycelia, we prepared two series of living cultures exposed either long-term or short-term to 2,7-dichlorodibenzo-p-dioxin (2,7-DCDD), and compared the decreases in the remaining amounts of this model compound. We chose Bjerkandera adusta strain VH57 as a promising new candidate for dioxin degradation, because it gave 40% difference in 2,7-DCDD levels between the two treatments after 30 days of exposure.