Spruce bark beetle Ips typographus can trigger outbreaks on spruce that results in significant losses in the forest industry. It has been suggested that symbiotic microorganisms inhabiting the gut of bark beetles facilitate the colonization of plant tissues as they play a role in the detoxification of plant secondary metabolites, degrade plant cell wall and ameliorate beetle's nutrition. In this study, we sequenced and functionally annotated the genomes of five yeasts Kuraishia molischiana, Cryptococcus sp., Nakazawaea ambrosiae, Ogataea ramenticola, and Wickerhamomyces bisporus isolated from the gut of Ips typographus. Genome analysis identified 5314, 7050, 5722, 5502, and 5784 protein coding genes from K. molischiana, Cryptococcus sp., N. ambrosiae, O. ramenticola, and W. bisporus, respectively. Protein-coding sequences were classified into biological processes, cellular and molecular function based on gene ontology terms enrichment. Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation was used to predict gene functions. All analyzed yeast genomes contain full pathways for the synthesis of essential amino acids and vitamin B6, which have nutritional importance to beetle. Furthermore, their genomes contain diverse gene families related to the detoxification processes. The prevalent superfamilies are aldo-keto reductase, ATP-binding cassette and the major facilitator transporters. The phylogenetic relationships of detoxification-related enzymes aldo-keto reductase, and cytochrome P450 monooxygenase, and ATP-binding cassette are presented. Genome annotations also revealed presence of genes active in lignocellulose degradation. In vitro analyses did not confirm enzymatic endolytic degradation of lignocellulose; however, all species can utilize and pectin and produce a large spectrum of exolytic enzymes attacking cellulose, chitin, and lipids.

• Klíčová slova
• Scolytinae, detoxification, gut microbiome, nutrition, plant cell wall, spruce, symbiosis, yeast,
• Publikační typ
• časopisecké články MeSH

A batch culture technique was used to evaluate dry matter (DM) digestibility of corn stover (Zea mays L.) and kudzu, Pueraria montana (Lour.) Merr. after solid-state fermentation (SSF) with a white-rot fungus, Pleurotus ostreatus (Jacq. ex Fr.) P. Kumm. Five dietary treatments consisting of mixtures of corn stover (C) and kudzu (K) in varying ratios, (1) 100C:0K, (2) 75C:25K, (3) 50C:50K, (4) 25C:75K, and (5) 0C:100K, were inoculated with P. ostreatus (MBFBL 400) and subjected to SSF for 0, 35, and 77 days. The study was arranged as a 5 × 3 factorial design with 3 replicates. Grass hay was included in the study as a control. Interactions (P < 0.05) between treatments and fermentation time were noted for the fermentation kinetics. Asymptotic gas was the highest (P < 0.05) for 0C:100K and 100C:0K on day 77. Treatment effect (P < 0.001) and treatment × fermentation time interaction (P < 0.001) were noted for in vitro dry matter digestibility (IVDMD). On day 77, treatment 4 had the highest (P < 0.001) IVDMD value, while treatment 1 had the lowest (P < 0.001) IVDMD. There was no difference (P > 0.05) between treatments 3, 5, and control. Numerically, the ranking of their IVDMD values from the highest to the lowest is 4 > 2 > 5 > control >3 > 1. The results show that the treated corn stover and kudzu mixes were comparable with the control, which is good quality hay. This is the first report that demonstrates the potential use of a combined mixture of corn stover and kudzu in ruminant animal feed development.

• MeSH
• biomasa MeSH
• fermentace MeSH
• kinetika MeSH
• krmivo pro zvířata analýza   mikrobiologie   MeSH
• kukuřice setá chemie   mikrobiologie   MeSH
• nutriční hodnota * MeSH
• Pleurotus metabolismus   MeSH
• plyny metabolismus   MeSH
• Pueraria chemie   mikrobiologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• plyny MeSH

Anthropogenic climate change, principally induced by the large volume of carbon dioxide emission from the global economy driven by fossil fuels, has been observed and scientifically proven as a major threat to civilization. Meanwhile, fossil fuel depletion has been identified as a future challenge. Lignocellulosic biomass in the form of organic residues appears to be the most promising option as renewable feedstock for the generation of energy and platform chemicals. As of today, relatively little bioenergy comes from lignocellulosic biomass as compared to feedstock such as starch and sugarcane, primarily due to high cost of production involving pretreatment steps required to fragment biomass components via disruption of the natural recalcitrant structure of these rigid polymers; low efficiency of enzymatic hydrolysis of refractory feedstock presents a major challenge. The valorization of lignin and cellulose into energy products or chemical products is contingent on the effectiveness of selective depolymerization of the pretreatment regime which typically involve harsh pyrolytic and solvothermal processes assisted by corrosive acids or alkaline reagents. These unselective methods decompose lignin into many products that may not be energetically or chemically valuable, or even biologically inhibitory. Exploring milder, selective and greener processes, therefore, has become a critical subject of study for the valorization of these materials in the last decade. Efficient alternative activation processes such as microwave- and ultrasound irradiation are being explored as replacements for pyrolysis and hydrothermolysis, while milder options such as advanced oxidative and catalytic processes should be considered as choices to harsher acid and alkaline processes. Herein, we critically abridge the research on chemical oxidative techniques for the pretreatment of lignocellulosics with the explicit aim to rationalize the objectives of the biomass pretreatment step and the problems associated with the conventional processes. The mechanisms of reaction pathways, selectivity and efficiency of end-products obtained using greener processes such as ozonolysis, photocatalysis, oxidative catalysis, electrochemical oxidation, and Fenton or Fenton-like reactions, as applied to depolymerization of lignocellulosic biomass are summarized with deliberation on future prospects of biorefineries with greener pretreatment processes in the context of the life cycle assessment.

• Klíčová slova
• biorefinery, depolymerization, greener oxidation, life cycle analysis, lignocellulosic biomass, mild pretreatment,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

The production of renewable energy in agricultural biogas plants is being widely criticized because-among other things-most of the feedstock comes from purpose-grown crops like maize. These activities (generously subsidized in the Czech Republic) generate competitive pressure to other crops that are used for feeding or food production, worsening their affordability. Unique pretreatment technology that allows substitution of the purpose-grown crops by farming residues (such as husk or straw) was built 6 years ago on a commercial basis in Pěčín (Czech Republic) under modest funding and without publicity. The design of the concept; financial assessment and moral viewpoint were analyzed based on practical operating data. It showed that the apparatus improves economic, environmental and moral acceptance as well. However, according to the government's view, public funding for this type of processing was shortened, "because waste materials represent a lower cost". The impact of such governance was analyzed as well.

• Klíčová slova
• Environmental assessment, Financial analysis, Moral consideration, Process management, Renewable energy,
• MeSH
• biopaliva * MeSH
• elektrárny MeSH
• financování vládou MeSH
• lidé MeSH
• mravy MeSH
• náklady a analýza nákladů MeSH
• průmyslový odpad * MeSH
• technologie * ekonomika   etika   MeSH
• zachování přírodních zdrojů * MeSH
• zachování zdrojů energie * MeSH
• zásobování potravinami * ekonomika   etika   MeSH
• zemědělské plodiny MeSH
• zemědělství * ekonomika   etika   MeSH
• životní prostředí MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• biopaliva * MeSH
• průmyslový odpad * MeSH

Notable progress has been achieved in the past two decades regarding production of different enzymatic mixtures for hydrolysis of the lignocellulose matrix. Nevertheless, the hydrolysing mixtures remain slow and require tempering, which results in high-energy demands and bad financial results. Use of acids or alkali at a very high temperature and pressure accelerates the process more than ten times wherein the energy requirements are approximately equal. However, these elevated reaction conditions might cause the breakdown of complex lignin formula into substances that have the potential to inhibit subsequent fermentation processes. Formation of these breakdown products may be prevented by selecting the optimum process parameters, but their acquisition requires either a large number of expensive analytical techniques or equally large amounts of slow fermentation tests. An inexpensive and time saving alternative that is based on the sensitivity of chosen organisms to these inhibitors was designed and financially assessed. It was confirmed that the method is technically feasible and economically viable with significant potential to reduce the bioethanol production cost.

• Klíčová slova
• Bioethanol, Financial analysis, Process management, Techno-economical assessment, Valuation,
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH

Pleurotus pulmonarius was cultivated on a corncob-based substrate for producing of mushrooms and for assessing the transformation of the lignocellulosics during the development of fungal biomass. Associated events, such as the release of relevant enzymes and the H2O2 generation, were also monitored. The peaks of laccase and catalase activities occurred at the 5th day and that of Mn peroxidase at the 30th day, simultaneously with a high activity of superoxide dismutase. Increase in the endocellulase and xylanase activities was observed after 10 days, with maximal activities achieved during the 20-30-day period. Maximal values of H2O2 were found after 10 days of cultivation. Electron microscopy and Fourier transform infrared (FTIR) spectroscopy showed strong alterations in the lignocellulosic fibers. The uncultivated and the cultivated substrates at different times were hydrolyzed with commercial cellulase and β-glucosidase. The highest values of reducing sugars (110.5 ± 5.6 μmol/mL), being 65 % glucose, were obtained using the 20-day cultivated substrate. After the fruiting stage (first flush), enzymatic hydrolysis of the spent mushroom substrate (SMS) yielded 53.0 ± 2.8 and 77.5 ± 4.0 μmol/mL of glucose and total reducing sugars, respectively. Although the release of reducing sugars of the P. pulmonarius SMS was lower than that obtained after 20 days of cultivation, it was still 50 % higher than that obtained using the uncultured substrate. This observation, combined with the fact that SMS constitutes a residue generated as a by-product of the depletion of an agro-industrial residue, allows to conclude that this material offers an interesting economic perspective for the obtainment of cellulosic ethanol.

• MeSH
• elektronová mikroskopie MeSH
• enzymy analýza   MeSH
• kukuřice setá chemie   mikrobiologie   ultrastruktura   MeSH
• lignin analýza   MeSH
• peroxid vodíku analýza   MeSH
• Pleurotus růst a vývoj   metabolismus   MeSH
• spektroskopie infračervená s Fourierovou transformací MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• enzymy MeSH
• lignin MeSH
• lignocellulose MeSH Prohlížeč
• peroxid vodíku MeSH