Improving cellulase production by Aspergillus niger using adaptive evolution

Microbial Biotechnolog

Сутність і теоретичні підходи до аналізу фінансової нестабільності

У статті розкрито сутність поняття «фінансова нестабільність». Розглянуто найбільш поширені в науковій літературі визначення фінансової нестабільності. Досліджено різні теоретичні підходи до аналізу виникнення явища фінансової нестабільності.В статье раскрыта сущность понятия «финансовая нестабильность». Рассмотрены наиболее распространенные в научной литературе определения финансовой нестабильности. Исследованы различные теоретические подходы к анализу возникновения явления финансовой нестабильности.The article reveals the essence of the concept of financial instability. The most popular definitions of financial instability in the scientific literature are considered. Various theoretical approaches of the phenomenon of financial instability are investigated

«Золота» пора кооперації в умовах непу

Рецензія на книгу: Голець В.В. Кооперація і неп (20-і рр. XX ст.). - Чернігів: Просвіта, 2006. - 244 с

Genome sequence of the button mushroom Agaricus bisporus reveals mechanisms governing adaptation to a humic-rich ecological niche

Agaricus bisporus is the model fungus for the adaptation, persistence, and growth in the humic-rich leaf-litter environment. Aside from its ecological role, A. bisporus has been an important component of the human diet for over 200 y and worldwide cultivation of the "button mushroom" forms a multibillion dollar industry. We present two A. bisporus genomes, their gene repertoires and transcript profiles on compost andduringmushroomformation.The genomes encode a full repertoire of polysaccharide-degrading enzymes similar to that of wood-decayers. Comparative transcriptomics of mycelium grown on defined medium, casing-soil, and compost revealed genes encoding enzymes involved in xylan, cellulose, pectin, and protein degradation aremore highly expressed in compost. The striking expansion of heme-thiolate peroxidases and β-etherases is distinctive from Agaricomycotina wood-decayers and suggests a broad attack on decaying lignin and related metabolites found in humic acid-rich environment. Similarly, up-regulation of these genes together with a lignolytic manganese peroxidase, multiple copper radical oxidases, and cytochrome P450s is consistent with challenges posed by complex humic-rich substrates. The gene repertoire and expression of hydrolytic enzymes in A. bisporus is substantially different from the taxonomically related ectomycorrhizal symbiont Laccaria bicolor. A common promoter motif was also identified in genes very highly expressed in humic-rich substrates. These observations reveal genetic and enzymatic mechanisms governing adaptation to the humic-rich ecological niche formed during plant degradation, further defining the critical role such fungi contribute to soil structure and carbon sequestration in terrestrial ecosystems. Genome sequence will expedite mushroom breeding for improved agronomic characteristics

The physiology of Agaricus bisporus in semi-commercial compost cultivation appears to be highly conserved among unrelated isolates

The white button mushroom Agaricus bisporus is one of the most widely produced edible fungus with a great economical value. Its commercial cultivation process is often performed on wheat straw and animal manure based compost that mainly contains lignocellulosic material as a source of carbon and nutrients for the mushroom production. As a large portion of compost carbohydrates are left unused in the current mushroom cultivation process, the aim of this work was to study wild-type A. bisporus strains for their potential to convert the components that are poorly utilized by the commercial strain A15. We therefore focused our analysis on the stages where the fungus is producing fruiting bodies. Growth profiling was used to identify A. bisporus strains with different abilities to use plant biomass derived polysaccharides, as well as to transport and metabolize the corresponding monomeric sugars. Six wild-type isolates with diverse growth profiles were compared for mushroom production to A15 strain in semi-commercial cultivation conditions. Transcriptome and proteome analyses of the three most interesting wild-type strains and A15 indicated that the unrelated A. bisporus strains degrade and convert plant biomass polymers in a highly similar manner. This was also supported by the chemical content of the compost during the mushroom production process. Our study therefore reveals a highly conserved physiology for unrelated strains of this species during growth in compost.Peer reviewe

The genome of the white-rot fungus Pycnoporus cinnabarinus : a basidiomycete model with a versatile arsenal for lignocellulosic biomass breakdown

Background: Saprophytic filamentous fungi are ubiquitous micro-organisms that play an essential role in photosynthetic carbon recycling. The wood-decayer Pycnoporus cinnabarinus is a model fungus for the study of plant cell wall decomposition and is used for a number of applications in green and white biotechnology.Results: The 33.6 megabase genome of P. cinnabarinus was sequenced and assembled, and the 10,442predicted genes were functionally annotated using a phylogenomic procedure. In-depth analyses were carried out for the numerous enzyme families involved in lignocellulosic biomass breakdown, for protein secretion and glycosylation pathways, and for mating type. The P. cinnabarinus genome sequence revealed a consistent repertoire of genes shared with wood-decaying basidiomycetes. P. cinnabarinus is thus fully equipped with the classical families involved in cellulose and hemicellulose degradation, whereas its pectinolytic repertoire appears relatively limited. In addition, P. cinnabarinus possesses a complete versatile enzymatic arsenal for lignin breakdown. We identified several genes encoding members of the three ligninolytic peroxidase types, namely lignin peroxidase, manganese peroxidase and versatile peroxidase. Comparative genome analyses were performed in fungi displaying different nutritional strategies (white-rot and brown-rot modes of decay). P. cinnabarinus presents a typical distribution of all thespecific families found in the white-rot life style. Growth profiling of P. cinnabarinus was performed on 35 carbon sources including simple and complex substrates to study substrate utilization and preferences. P. cinnabarinus grew faster on crude plant substrates than on pure, mono- or polysaccharide substrates. Finally, proteomic analyses were conducted from liquid and solid-state fermentation to analyze the composition of the secretomes corresponding to growth on different substrates. The distribution of lignocellulolytic enzymes in the secretomes was strongly dependent on growth conditions, especially for lytic polysaccharide mono-oxygenases.Conclusions: With its available genome sequence, P. cinnabarinus is now an outstanding model system for the study of the enzyme machinery involved in the degradation or transformation of lignocellulosic biomass.Microbial Biotechnolog

Progress and Research Needs of Plant Biomass Degradation by Basidiomycete Fungi

Peer reviewe

The Paleozoic Origin of Enzymatic Lignin Decomposition Reconstructed from 31 Fungal Genomes

Wood is a major pool of organic carbon that is highly resistant to decay, owing largely to the presence of lignin. The only organisms capable of substantial lignin decay are white rot fungi in the Agaricomycetes, which also contains non–lignin-degrading brown rot and ectomycorrhizal species. Comparative analyses of 31 fungal genomes (12 generated for this study) suggest that lignin-degrading peroxidases expanded in the lineage leading to the ancestor of the Agaricomycetes, which is reconstructed as a white rot species, and then contracted in parallel lineages leading to brown rot and mycorrhizal species. Molecular clock analyses suggest that the origin of lignin degradation might have coincided with the sharp decrease in the rate of organic carbon burial around the end of the Carboniferous period

Fate of Lignin and Substituted Xylan during Commercial Cultivation of Agaricus bisporus

Wheat straw based compost is the substrate for commercial growth of Agaricus bisporusmushrooms, but it is unknown to which extent the carbohydrate-lignin matrix changes and howmuch is metabolized during commercial cultivation. In this paper we report yields and remainingstructures of the major compost carbohydrates and lignin. Hereto, a mass balance was conducted ina tunnel-experiment at industrial scale, and total dry matter, cellulose, hemicellulosic xylan andlignin were quantified (Jurak et al., 2015a). Remaining (substituted) xylan structures were extractedand analysed in detail by enzymatic fingerprinting with use of HPAEC and MALDI-TOF MS.Remaining lignin structures were subjected to analytical pyrolysis GC/MS and typical lignin unitswere determined. In addition, to determine why certain fractions remain unused in the compost,activities of water extracted carbohydrate degrading enzymes were analysed for their ability todegrade a range of polysaccharides (Jurak et al., 2015b,c). During growth of A. bisporus,carbohydrates were only slightly consumed and xylan was partially degraded. At the same time,lignin was metabolized for 45% based on pyrolysis GC/MS. Remaining lignin was modified, asobserved by an increase in the ratio of syringyl (S) to guaiacyl (G) units from 0.5 to 0.7 duringgrowth, while fewer decorations on the phenolic skeleton of both S and G units remained (Jurak etal., 2015a). During mushroom formation, mainly endo-xylanase, endo-glucanase, β-xylosidase andβ-glucosidase activities were determined in the compost extracts. Arabinofuranosidase activity ableto remove arabinosyl residues from doubly substituted xylosyl residues nor α-glucuronidase activitywere detected (Jurak et al., 2015b). The latter correlated with the observed accumulation of xylanfragments substituted with arabinosyl and glucuronic acid substituents in the compost towards theend of the cultivation (Jurak et al., 2015c). Hence, it was concluded that compost grown A. bisporuslacks the ability to degrade and consume highly substituted xylan fragments