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Research demonstrates that Stropharia coronilla metabolizes and mineralizes benzo[a]pyrene and manganese(II) ions significantly stimulate this process by four to twelve times, respectively. Data indicate that the stimulatory effects is mediated by the ligninolytic enzyme manganese peroxidase, whose activity increases upon manganese addition.

Results demonstrate that Collybia dryophilla K209, which colonize forest litter and soil, decomposes a natural and a synthetic humic acid with the degradation leading to the formation of polar, fulvic acid and carbon dioxide. Data indicate that manganese subsantially enhances humic acid decomposition, presumably mediated by manganese peroxidase.

While it is known that several Actinobacteria produce enzymes that decompose polysaccharides or phenolic compounds in dead plant biomass, the occurrence of these traits in the environment remains largely unclear. The aim of this work was to screen isolated actinobacterial strains to explore their ability to produce extracellular enzymes that participate in the degradation of polysaccharides and their ability to cometabolically transform phenolic compounds of various complexities. Actinobacterial strains were isolated from meadow and forest soils and screened for their ability to grow on lignocellulose. The potential to transform 14C-labelled phenolic substrates (dehydrogenation polymer (DHP), lignin and catechol) and to produce a range of extracellular, hydrolytic enzymes was investigated in three strains of Streptomyces spp. that possessed high lignocellulose degrading activity. Isolated strains showed high variation in their ability to produce cellulose- and hemicellulose-degrading enzymes and were able to mineralise up to 1.1% and to solubilise up to 4% of poplar lignin and to mineralise up to 11.4% and to solubilise up to 64% of catechol, while only minimal mineralisation of DHP was observed. The results confirm the potential importance of Actinobacteria in lignocellulose degradation, although it is likely that the decomposition of biopolymers is limited to strains that represent only a minor portion of the entire community, while the range of simple, carbon-containing compounds that serve as sources for actinobacterial growth is relatively wide. [ABSTRACT FROM AUTHOR]

While it is known that several Actinobacteria produce enzymes that decompose polysaccharides or phenolic compounds in dead plant biomass, the occurrence of these traits in the environment remains largely unclear. The aim of this work was to screen isolated actinobacterial strains to explore their ability to produce extracellular enzymes that participate in the degradation of polysaccharides and their ability to cometabolically transform phenolic compounds of various complexities. Actinobacterial strains were isolated from meadow and forest soils and screened for their ability to grow on lignocellulose. The potential to transform 14C-labelled phenolic substrates (dehydrogenation polymer (DHP), lignin and catechol) and to produce a range of extracellular, hydrolytic enzymes was investigated in three strains of Streptomyces spp. that possessed high lignocellulose degrading activity. Isolated strains showed high variation in their ability to produce cellulose- and hemicellulose-degrading enzymes and were able to mineralise up to 1.1% and to solubilise up to 4% of poplar lignin and to mineralise up to 11.4% and to solubilise up to 64% of catechol, while only minimal mineralisation of DHP was observed. The results confirm the potential importance of Actinobacteria in lignocellulose degradation, although it is likely that the decomposition of biopolymers is limited to strains that represent only a minor portion of the entire community, while the range of simple, carbon-containing compounds that serve as sources for actinobacterial growth is relatively wide. [ABSTRACT FROM AUTHOR]

Yuchengia gen. nov. is proposed to accommodate Perenniporia narymica. It represents a monophyletic lineage within the core polyporoid clade based on sequences of the rDNA ITS and nLSU regions, and it is distinct from Perenniporia s.s. Yuchengia shares some characters with Perenniporia, both having thick-walled and cyanophilous basidiospores, but differs by having acyanophilous and amyloid skeletal hyphae dissolving in KOH, and non-dextrinoid basidiospores. [ABSTRACT FROM AUTHOR]

The ability of 60 white-rot fungal strains (38 species) to decolourise six structurally different synthetic dyes, namely Congo red, Orange G, Alizarin red, Crystal violet, Neutral red and Methylene blue, which, respectively, belong to the azo, anthraquinone-based, triphenylmethane and heterocyclic dye groups, were investigated by agar plate tests. Effects of different culture conditions on the decolourisation of Alizarin red by the Chinese-specific species of white-rot fungus, Antrodiella albocinnamomea, were investigated using liquid cultures. The results show that most of the isolates had the capacity to decolourise all synthetic dyes. Antrodiella albocinnamomea was first reported as having a strong decolourizing capacity and is closely related to Cerrena unicolor in the phylogenetic tree. In liquid culture, the optimum pH was 5.5 and, compared to other carbon and nitrogen sources tested, glucose and malt extracts resulted in the best decolourisation performances. The high activity of laccase produce by A. albocinnamomea was mainly responsible for its high decolourisation efficiency. [ABSTRACT FROM AUTHOR]

Abstract: Litter decomposing basidiomycetous fungi produce ligninolytic oxidases and peroxidases which are involved in the transformation of lignin, as well as humic and fulvic acids. The aim of this work was to evaluate their importance in lignin transformation in forest litter. Two litter decomposing basidiomycete species differing in their abilities to degrade lignin –Hypholoma fasciculare, and Gymnopus erythropus – were cultured on sterile or non-sterile oak litter and their transformation of a 14C-labelled synthetic lignin (dehydrogenation polymer 14C-DHP) was compared with that of the indigenous litter microflora. Both in sterile and non-sterile litter, colonisation by basidiomycetes led to higher titres of lignocellulose-degrading enzymes, in particular of laccase and Mn-peroxidase (MnP). The titres of the latter were 6 to 40-fold increased in the presence of basidiomycetes compared to non-sterile litter. During 10 weeks, G. erythropus mineralised over 31% of 14C-DHP in sterile litter and 23% in non-sterile litter compared to 14% in the non-sterile control. Lignin mineralization by H. fasciculare was comparable to the non-sterile control, 12% in sterile litter and 16% in the non-sterile litter. The largest part of 14C from 14C-DHP was transformed into humic compounds during litter treatment with both fungi as well as in the control. In addition to the fast lignin mineralization, microcosms containing G. erythropus also showed a lower final content of unaltered lignin and 23–28% of the lignin was converted into water-soluble compounds with relatively low molecular mass (<5kDa). Both G. erythropus and H. fasciculare were also able to further mineralise humic compounds. During a 10-week fungal treatment of an artificial 14C-humic acid (14C-HA) supplemented to the natural humic material of a forest soil, the fungi mineralised 42% and 19% of the labelled material, respectively, under sterile conditions. The 14C-HA mineralization by introduced basidiomycetes in microcosms containing non-sterile humic material, however, did not significantly differ from that of a non-sterile control and was around 12%. Altogether the results show that saprobic basidiomycetes can considerably differ in their rates of lignin and humic substance conversion. Furthermore, lignin degradation in forest soil can rather slow down by interspecific competition than it is accelerated by cooperation of different microorganisms occupying specific nutritional niches. Therefore, the overall contribution of saprobic basidiomycetes depends on their particular eco-physiological status and the competitive pressure, and may be often lower than initially expected. Significant lignin transformation including partial mineralization is seemingly not exclusively dependent on exceptional high titres of ligninolytic enzymes but also on so far unknown factors. Higher endocellulase production and subsequent weight loss was found in microcosms where saprobic basidiomycetes were combined with indigenous microbes. Potentially, lignin degradation by the basidiomycetes may have increased cellulose availability to the indigenous microbes. [Copyright &y& Elsevier]

The shooting range site at Hälvälä in southern Finland is heavily contaminated by lead pellets. Still, the appearance of the forest is not visibly changed. Lead contamination strongly decreased the amount of enchytraeid worms, while reporter bacteria showed no or very minor decrease in viability. The bioavailability of lead in the soil was measured to be low, which was verified by the very low water extractability of lead. Nevertheless, the frequency of lead resistant cultivable bacteria was elevated, and the bacterial community composition in lead contaminated soil was altered. Some enzymes of litter decomposing fungi isolated from Hälvälä also showed an elevated lead tolerance, though generally their activity was highly variable and in some cases lead enhanced enzyme production of a fungus. In conclusion, our results point to a low acute toxicity of lead, but to a risk of deleterious long term effects in a pine forest environment. [ABSTRACT FROM AUTHOR]

The soil moldPaecilomyces inflatusis capable of modifying and partially mineralizing synthetic and natural humic acids (HAs) in compost environments. HA degradation studies using a synthetic HA (14C-HA) in autoclaved compost microcosms showed that, after 12 weeks of cultivation,P. inflatusmineralized approximately 5% of the14C-labeled HA to14CO2, while 6% of the14C-HA was converted into14C-labeled water-soluble fragments (fulvic-acid-like fraction). About 40% was still present as NaOH-soluble HA representing unmodified or only slightly modified humic material (compared with 60% in the controls). Modification of natural HAs extracted from compost was followed by their partial decolorization (30%) in liquid cultures ofP. inflatus. Bleaching of the medium was accompanied by moderate changes in the molecular mass distribution of both the HA and fulvic-acid fractions, which were analyzed with high-performance size exclusion chromatography. HA modification was most pronounced during the primary growth phase of the fungus and was associated with increased laccase activity. [ABSTRACT FROM AUTHOR]

Examines the basidiomycete Collybia dryophila decomposed on humic acid isolated from pine-forest litter. Synthesis of [sub 14]C-labeled humic acid prepared from catechol in liquid culture; Formation of polar, lower-molecular-mass fulvic acid and carbon dioxide; Identification of manganese peroxide in supplemented cultures.