Microbial and enzymatic degradation of keratin waste is more preferred over various conventional approaches which are costly and not environmentally suitable. Diverse niches are auspicious for the discovery of new microorganisms. To discover novel keratinolytic bacteria, 60 isolates from different poultry dumping sites were initially screened, and among these found a potent keratinolytic isolate (NKSP-7) that displayed higher feather-degrading ability. The selected isolate was identified as Bacillus sp. NKSP-7 based on 16S rDNA sequencing as well as physiochemical and morphological characteristics. The strain NKSP-7 showed complete hydrolysis of native chicken feathers (10 g/L) in nutrient medium after 24 h of incubation at 37 °C under agitation (150 rev/min) and produced thermostable extracellular keratinase. The crude enzyme displayed maximal keratinolytic activity (34.7 U/mL) in phosphate buffer of pH 7.0, and at 60 °C using keratin azure as a substrate. Keratinolytic enzyme showed stability at 20-65 °C for 4 h over the pH range of 5.5-8.0. No obvious inhibitory influence was perceived by cations, organic solvents, EDTA, and detergents. Whereas, enzyme activity was enhanced by adding β-mercaptoethanol, Na+, Cd2+, and Mn2+. All these notable features of keratinase make it a promising candidate for various industrial applications especially for dehairing process in leather industry, bioconversion of poultry waste, and in detergents formulations.
- MeSH
- Bacillus klasifikace genetika izolace a purifikace metabolismus MeSH
- bakteriální proteiny chemie genetika metabolismus MeSH
- biodegradace MeSH
- drůbež * MeSH
- fermentace MeSH
- keratiny analýza metabolismus MeSH
- koncentrace vodíkových iontů MeSH
- kur domácí MeSH
- molekulová hmotnost MeSH
- odpadky - odstraňování metody MeSH
- peří chemie metabolismus MeSH
- proteasy chemie genetika metabolismus MeSH
- proteolýza MeSH
- RNA ribozomální 16S genetika MeSH
- teplota MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The laterite Ni ore smelting operations in Niquelândia and Barro Alto (Goiás State, Brazil) have produced large amounts of fine-grained smelting wastes, which have been stockpiled on dumps and in settling ponds. We investigated granulated slag dusts (n = 5) and fly ash samples (n = 4) with a special focus on their leaching behaviour in deionised water and on the in vitro bioaccessibility in a simulated gastric fluid, to assess the potential exposure risk for humans. Bulk chemical analyses indicated that both wastes contained significant amounts of contaminants: up to 2.6 wt% Ni, 7580 mg/kg Cr, and 508 mg/kg Co. In only one fly ash sample, after 24 h of leaching in deionised water, the concentrations of leached Ni exceeded the limit for hazardous waste according to EU legislation, whereas the other dusts were classified as inert wastes. Bioaccessible fractions (BAF) of the major contaminants (Ni, Co, and Cr) were quite low for the slag dusts and accounted for less than 2 % of total concentrations. In contrast, BAF values were significantly higher for fly ash materials, which reached 13 % for Ni and 19 % for Co. Daily intakes via oral exposure, calculated for an adult (70 kg, dust ingestion rate of 50 mg/day), exceeded neither the tolerable daily intake (TDI) nor the background exposure limits for all of the studied contaminants. Only if a higher ingestion rate is assumed (e.g. 100 mg dust per day for workers in the smelter), the TDI limit for Ni recently defined by European Food Safety Authority (196 µg/day) was exceeded (324 µg/day) for one fly ash sample. Our data indicate that there is only a limited risk to human health related to the ingestion of dust materials generated by laterite Ni ore smelting operations if appropriate safety measures are adopted at the waste disposal sites and within the smelter facility.
- MeSH
- anorganické látky aplikace a dávkování MeSH
- aplikace orální MeSH
- biologické modely MeSH
- chrom analýza MeSH
- hutnictví * MeSH
- kobalt analýza MeSH
- lidé MeSH
- nebezpečný odpad analýza MeSH
- nikl analýza MeSH
- odpadky - odstraňování metody MeSH
- popel uhelný analýza MeSH
- prach analýza MeSH
- průmyslový odpad MeSH
- vystavení vlivu životního prostředí * MeSH
- žaludeční šťáva MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Brazílie MeSH
This work investigates the potential bioconversion of spent coffee grounds (SCG) into lactic acid (LA). SCG were hydrolysed by a combination of dilute acid treatment and subsequent application of cellulase. The SCG hydrolysate contained a considerable amount of reducing sugars (9·02 ± 0·03 g l-1 , glucose; 26·49 ± 0·10 g l-1 galactose and 2·81 ± 0·07 g l-1 arabinose) and it was used as a substrate for culturing several lactic acid bacteria (LAB) and LA-producing Bacillus coagulans. Among the screened micro-organisms, Lactobacillus rhamnosus CCM 1825 was identified as the most promising producer of LA on a SCG hydrolysate. Despite the inhibitory effect exerted by furfural and phenolic compounds in the medium, reasonably high LA concentrations (25·69 ± 1·45 g l-1 ) and yields (98%) were gained. Therefore, it could be demonstrated that SCG is a promising raw material for the production of LA and could serve as a feedstock for the sustainable large-scale production of LA. SIGNIFICANCE AND IMPACT OF THE STUDY: Spent coffee grounds (SCG) represent solid waste generated in millions of tonnes by coffee-processing industries. Their disposal represents a serious environmental problem; however, SCG could be valorized within a biorefinery concept yielding various valuable products. Herein, we suggest that SCG can be used as a complex carbon source for the lactic acid production.
- MeSH
- Bacillus coagulans enzymologie metabolismus MeSH
- bioreaktory mikrobiologie MeSH
- biotechnologie MeSH
- celulasa metabolismus MeSH
- fermentace MeSH
- hydrolýza MeSH
- káva chemie metabolismus MeSH
- kyselina mléčná biosyntéza MeSH
- Lacticaseibacillus rhamnosus enzymologie metabolismus MeSH
- odpadky - odstraňování metody MeSH
- tuhý odpad MeSH
- Publikační typ
- časopisecké články MeSH
Dust emissions from copper smelters processing arsenic-bearing ores represent a risk to soil environments due to the high levels of As and other inorganic contaminants. Using an in situ experiment in four different forest and grassland soils (pH 3.2-8.0) we studied the transformation of As-rich (>50 wt% As) copper smelter dust over 24 months. Double polyamide bags with 1 g of flue dust were buried at different depths in soil pits and in 6-month intervals; then those bags, surrounding soil columns, and soil pore waters were collected and analysed. Dust dissolution was relatively fast during the first 6 months (5-34%), and mass losses attained 52% after 24 months. The key driving forces affecting dust dissolution were not only pH, but also the water percolation/retention in individual soils. Primary arsenolite (As2O3) dissolution was responsible for high As release from the dust (to 72%) and substantial increase of As in the soil (to a 56 × increase; to 1500 mg kg-1). Despite high arsenolite solubility, this phase persisted in the dust after 2 years of exposure. Mineralogical investigation indicated that mimetite [Pb5(AsO4)3(Cl,OH)], unidentified complex Ca-Pb-Fe-Zn arsenates, and Fe oxyhydroxides partly controlled the mobility of As and other metal(loid)s. Compared to As, other less abundant contaminants (Bi, Cu, Pb, Sb, Zn) were released into the soil to a lesser extent (8-40% of total). The relatively high mobility of As in the soil can be seen from decreases of bulk As concentrations after spring snowmelt, high water-extractable fractions with up to ∼50% of As(III) in extracts, and high As concentrations in soil pore waters. Results indicate that efficient controls of emissions from copper smelters and flue dust disposal sites are needed to prevent extensive contamination of nearby soils by persistent As.
A microscale discontinuous fermenter was used for anaerobic digestion of wine waste - a hardly gasifiable feedstock material. Efficiency of biogas production, i.e. changes in content of nitrogen, oxygen, carbon dioxide and methane in gas phase, was monitored by gas chromatography/mass spectrometry. Liquid chromatography/high resolution tandem mass spectrometry in combination with principal component analysis and orthogonal projection to latent structures was used to reveal main chemical differences of gasified wine waste mixture from commonly used ones in agricultural biogas plants. Compounds with particular polyphenolic structures appeared among the most distinctive markers. Analysis of samples collected during acidogenic phase and unstabilized methanogenesis indicates formation of certain dihydro-flavonoids in early stages of the process and their consequent degradation. Due to formerly described higher toxicity of some dihydroflavonoids (e.g. taxifolin) compared to their more common counterparts (e.g. quercetin, malvidin etc.), unstabilized digestate would represent a potential environmental risk when used as a fertilizer deserving a proper control.
- MeSH
- anaerobióza MeSH
- biopaliva analýza MeSH
- bioreaktory MeSH
- chromatografie kapalinová metody MeSH
- dusík analýza MeSH
- methan analýza MeSH
- odpadky - odstraňování metody MeSH
- polyfenoly chemie metabolismus MeSH
- potravinářský průmysl MeSH
- průmyslová hnojiva analýza MeSH
- průmyslový odpad MeSH
- tandemová hmotnostní spektrometrie metody MeSH
- Vitis chemie MeSH
- Publikační typ
- časopisecké články MeSH
The research was focused on approximation of clogging in a leachate collection system in municipal solid waste landfill in Osecna, situated near the location Osecna, region Liberec, Northern Bohemia, Czech Republic, by analysis of numerical experiment results. To approximate the clogging of the leachate collection system after fifteen years of landfill operation (1995-2009) were successfully tested modified De Zeeuw-Hellinga transient drainage theory. This procedure allows application of the reduction factors to express clogging of the leachate collection system in Osecna landfill. The results proved that the modified De Zeeuw-Hellinga method with reduction factors can serve as a good tool for clogging approximation in a leachate collection system in Osecna landfill.
- MeSH
- chemické látky znečišťující vodu analýza MeSH
- odpadky - odstraňování metody MeSH
- skládková zařízení * MeSH
- tuhý odpad analýza MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
Large-scale vermicomposting under outdoor conditions may differ from small-scale procedures in the laboratory. The present study evaluated changes in selected properties of a large-scale vertical-flow windrow vermicomposting system with continuous feeding with household biowaste. The windrow profile was divided into five layers of differing thickness and age after more than 12 months of vermicomposting. The top layer (0-30 cm, age <3 months) was characterised by partially decomposed organic matter with a high pH value and an elevated carbon/nitrogen (C/N) ratio. The earthworm biomass was 15 g kg-1with a population density of 125 earthworms per kilogram predominantly found in clusters. The greatest amount of fungi (3.5 µg g-1dw) and bacteria (62 µg g-1dw) (expressed as phospholipid fatty acid analysis) was found in this layer. Thus, the top layer could be used for an additional cycle of windrow vermicomposting and for the preparation of aqueous extracts to protect plants against diseases. The lower layers (graduated by 30 cm and by 3 months of age) were mature as reflected by the low content of ammonia nitrogen, ratio of ammonia to nitrate nitrogen and dissolved organic carbon, and high ion-exchange capacity and its ratio to carbon. These layers were characterised by elevated values for electrical conductivity, total content of nutrients, available magnesium content, and a relatively large bacterial/fungal ratio. On the basis of the observed properties, the bottom layers were predetermined as effective fertilisers.
- MeSH
- biodegradace MeSH
- kompostování metody MeSH
- odpadky - odstraňování metody MeSH
- Oligochaeta * MeSH
- půda MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
In this study the feasibility of Eisenia andrei to digest great amount of wastes including horse manure (HM), apple pomace (AP), grape pomace (GP), and digestate (DG) was monitored through a continuous-feeding system. New layers of fresh material were gradually added to form an aged-profile of layers in order to understand the interaction between earthworms and microorganisms during vermicomposting. Thus, changes in chemical and biological parameters were evaluated for 240days. The earthworm population reached maximum values in 120 d-old-layer, which was related to an increase in overall microbial biomass, assayed as dehydrogenase activity, in all of the processed materials. The pH was generally alkaline or neutral in all of the materials. The electrical conductivity did not modify significantly during vermicomposting, except in the case of the processed GP, and DG. The stabilization, in all of the processed materials, was detected after 240 d of vermicomposting, as indicated the decline in the content of dissolved organic carbon (DOC). The N-NO3(-) content exhibited an enhanced in the processed HM and AP, while a generalized decreased was found in the GP, and DG materials in 240 d-old-layer. The decline in microbial biomass activity, in all processed substrates, was related to a decrease in the earthworm activity after 240 d of vermicomposting, indicating a high degree of stabilization. However, the β-glucosidase, phosphatase, protease, and o-diphenol oxidase activities were different according to the age of layers and type of processed material. The phytotoxicity test indicated that the end products of the processed AP and DG were chemically stable and enriched with nutrients in comparison with the HM and GP vermicompost. This fact indicates to stabilization (maturation) in the end product, which is important for its safe disposal as an organic nutrient-rich product.
- MeSH
- biodegradace * MeSH
- hnůj MeSH
- odpadky - odstraňování metody MeSH
- Oligochaeta fyziologie MeSH
- ovoce MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
An investigation was carried out on the effect of inoculation methods on the compost of an organic fraction of municipal solid waste. Three types of white-rot fungi (Phanerochaete chrysosporium, Trametes versicolor and Fomes fomentarius), and a consortium of these fungi, were used. The study assessed their influence on microbial enzymatic activities and the quality of the finished compost. It was found that the addition of white-rot fungi to municipal solid waste (after 37days of composting) could be a useful strategy for enhancing the properties of the final compost product. In comparison with the control sample (compost without inoculation), it accelerates degradation of solid waste as indicated by changes in C/N, electrical conductivity and pH. However, the effectiveness of waste degradation and compost maturation depends on the type of microorganism used for inoculation. The presence of inoculants, such as Trametes versicolor and Fomes fomentarius, led to a higher degrading ratio and a better degree of maturity. This resulted in an increase of enzymatic activities (especially dehydrogenase and protease) and a germination index in comparison with inoculation using Phanerochaete chrysosporium or a consortium of fungi.
- MeSH
- biodegradace MeSH
- Coriolaceae metabolismus MeSH
- dusík metabolismus MeSH
- enzymy metabolismus MeSH
- houby metabolismus MeSH
- koncentrace vodíkových iontů MeSH
- odpadky - odstraňování metody MeSH
- Phanerochaete metabolismus MeSH
- půda * MeSH
- půdní mikrobiologie * MeSH
- Trametes metabolismus MeSH
- tuhý odpad * MeSH
- uhlík metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
Steel plants generate significant amounts of wastes such as sludge, slag, and dust. Blast furnace sludge is a fine-grained waste characterized as hazardous and affecting the environment negatively. Briquetting is one of the possible ways of recycling of this waste while the formed briquettes serve as a feed material to the blast furnace. Several binders, both organic and inorganic, had been assessed, however, only the solid product had been analysed. The aim of this study was to assess the possibilities of briquetting using commonly available laundry starch as a binder while evaluating the possible utilization of the waste gas originating from the thermal treatment of the briquettes. Briquettes (100g) were formed with the admixture of starch (UNIPRET) and their mechanical properties were analysed. Consequently, they were subjected to thermal treatment of 900, 1000 and 1100°C with retention period of 40min during which was the waste gas collected and its content analysed using gas chromatography. Dependency of the concentration of the compounds forming the waste gas on the temperature used was determined using Principal component analysis (PCA) and correlation matrix. Starch was found to be a very good binder and reduction agent, it was confirmed that metallic iron was formed during the thermal treatment. Approximately 20l of waste gas was obtained from the treatment of one briquette; main compounds were methane and hydrogen rendering the waste gas utilizable as a fuel while the greatest yield was during the lowest temperatures. Preparation of blast furnace sludge briquettes using starch as a binder and their thermal treatment represents a suitable method for recycling of this type of metallurgical waste. Moreover, the composition of the resulting gas is favourable for its use as a fuel.
- MeSH
- analýza hlavních komponent MeSH
- biomasa MeSH
- biopaliva * MeSH
- chromatografie plynová MeSH
- difrakce rentgenového záření MeSH
- elektronová mikroskopie MeSH
- kovy chemie MeSH
- mechanický stres MeSH
- ocel chemie MeSH
- odpadky - odstraňování metody MeSH
- odpadní vody analýza MeSH
- plyny * MeSH
- prach MeSH
- průmyslový odpad MeSH
- recyklace metody MeSH
- spektrometrie rentgenová emisní MeSH
- vysoká teplota MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
