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Showing 1401 - 1205 of 1205 Journals sorted alphabetically
Transportation Research Record : Journal of the Transportation Research Board     Full-text available via subscription   (Followers: 34)
Transportmetrica A : Transport Science     Hybrid Journal   (Followers: 8)
Trends in Applied Sciences Research     Open Access   (Followers: 1)
Tribology in Industry     Open Access   (Followers: 4)
Tribology International     Hybrid Journal   (Followers: 46)
Tribology Letters     Hybrid Journal   (Followers: 7)
Tribology Transactions     Hybrid Journal   (Followers: 35)
Trilogía     Open Access  
Turkish Journal of Engineering     Open Access  
Turkish Journal of Engineering and Environmental Sciences     Open Access   (Followers: 1)
Türkiye Arazi Yönetimi Dergisi     Open Access  
Türkiye Coğrafi Bilgi Sistemleri Dergisi     Open Access  
Türkiye Fotogrametri Dergisi     Open Access  
Türkiye İnsansız Hava Araçları Dergisi     Open Access  
U.Porto Journal of Engineering     Open Access  
UKH Journal of Science and Engineering     Open Access  
Ultramicroscopy     Hybrid Journal   (Followers: 4)
Uludağ University Journal of The Faculty of Engineering     Open Access  
Uluslararası Mühendislik ve Teknoloji Araştırmaları Dergisi / International Journal of Engineering and Technology Research     Open Access  
Universal Journal of Applied Science     Open Access   (Followers: 2)
Universal Journal of Engineering Science     Open Access   (Followers: 2)
Universidad, Ciencia y Tecnología     Open Access   (Followers: 1)
Usak University Journal of Engineering Sciences     Open Access  
Utilities Policy     Hybrid Journal   (Followers: 2)
Vacuum     Hybrid Journal   (Followers: 12)
Vestnik of Don State Technical University     Open Access  
Vibration     Open Access   (Followers: 19)
Virtual and Physical Prototyping     Hybrid Journal   (Followers: 4)
Visualization in Engineering     Open Access   (Followers: 1)
Walailak Journal of Science and Technology     Open Access  
Waste and Biomass Valorization     Hybrid Journal   (Followers: 3)
Waste Management Series     Full-text available via subscription   (Followers: 1)
Waves in Random and Complex Media     Hybrid Journal  
Waves, Wavelets and Fractals - Advanced Analysis     Open Access  
Wear     Hybrid Journal   (Followers: 27)
Welding in the World     Hybrid Journal   (Followers: 7)
West African Journal of Industrial and Academic Research     Open Access   (Followers: 2)
World Electric Vehicle Journal     Open Access  
World Journal of Engineering and Technology     Open Access  
World Journal of Environmental Engineering     Open Access   (Followers: 3)
World Pumps     Full-text available via subscription   (Followers: 2)
World Science and Technology     Full-text available via subscription  
Yugra State University Bulletin     Open Access   (Followers: 1)
ZDM     Hybrid Journal   (Followers: 1)
Zede Journal     Open Access   (Followers: 1)
Zeitschrift für Arbeitswissenschaft     Hybrid Journal  
Zeitschrift fur Energiewirtschaft     Hybrid Journal  
Вісник Приазовського Державного Технічного Університету. Серія: Технічні науки     Open Access  

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Waste and Biomass Valorization
Journal Prestige (SJR): 0.434
Citation Impact (citeScore): 2
Number of Followers: 3  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1877-2641 - ISSN (Online) 1877-265X
Published by Springer-Verlag Homepage  [2626 journals]
  • Correction to: The Potential of Reformed Slag on the Mechanical and
           Thermal Behaviour of Toughened Unsaturated Polyester Composites
    • Abstract: The third author name was incorrectly published in the original publication of the article. The third author name should be Michaela Gedan Smolka.
      PubDate: 2020-08-01
       
  • Correction to: Valorisation of Potato ( Solanum tuberosum ) Peel Waste:
           Extraction of Fibre, Monosaccharides and Uronic Acids
    • Abstract: The article listed above was initially published with incorrect copyright information.
      PubDate: 2020-08-01
       
  • Improvement of Phenolic Contents and Antioxidant Activities of Longan (
           Dimocarpus longan ) Peel Extracts by Enzymatic Treatment
    • Abstract: This study demonstrated increases in the recovery of phenolic compounds from industrial waste, longan peel, after treatment with plant matrix degrading enzymes. Pretreatment of longan peel with cellulase, α-amylase, protease, or β-glucosidase enhanced total phenolic content in the extracts, leading to increases of DPPH scavenging activity, oxygen radical absorbance capacity, antioxidant in β-carotene/linoleate system, and ferrous ion chelating activity. In detail, cellulase increased the release of free phenolics e.g. o-coumaric acid, corilagin, and quercetin as well as the release of esterified phenolics e.g. ellagic acid, and gallic acid, while β-glucosidase increased the release of free phenolics e.g. ellagic acid. Among all enzymatic pretreatments, protease provided the highest proportion of phenolics’ recovery in the extract, while only cellulase and β-glucosidase significantly improved extraction yields by 31 and 17%, respectively. These results indicated enhancement of valorization of longan peel as a resource material for functional ingredients recovery. Graphic
      PubDate: 2020-08-01
       
  • Sugarcane Syrup Improves Xylitol Bioproduction from Sugarcane Bagasse and
           Straw Hemicellulosic Hydrolysate
    • Abstract: To evaluate the supplementation of the sugarcane bagasse and straw hemicellulosic hydrolysate with sugarcane syrup, which is a sucrose-rich co-product, for xylitol production by Candida guilliermondii FTI 20037. Recently, we demonstrated that sucrose supplementation to sugarcane straw hemicellulosic hydrolysate favoured this bioprocess. A mixture 1:1 of sugarcane bagasse and straw was submitted to dilute-acid hydrolysis with H2SO4 to obtain the hemicellulosic hydrolysate, which was concentrated, detoxified and autoclaved. Three sugarcane syrup concentrations (0.83, 2.50 and 3.33% v/v) were added to the hemicellulosic hydrolysate, which was also supplemented with rice bran extract, (NH4)2SO4, CaCl2·2H2O. Next, a full factorial design was performed to assess the replacement of conventional nutrients by sugarcane syrup. Fermentations were performed in 125 mL Erlenmeyer flasks containing 50 mL of fermentation medium, for 48 h at 30 °C and 200 rpm. Improvements of 16.85% and 12.24% in xylose uptake rate (1.04 ± 0.01 g L−1 h−1) and xylitol volumetric productivity (0.55 ± 0.02 g L−1 h−1), respectively, were achieved with syrup supplementation (2.50% v/v), which led to a final xylitol titer of 26.19 ± 0.02 g L−1. Conventionally employed nutrients (rice bran extract, (NH4)2SO4 and CaCl2·2H2O) did not have significant influence on xylitol production when sugarcane syrup was added to the fermentation medium. Sugarcane syrup as a nutritional supplement improved xylitol production from a mixture of bagasse and straw, becoming an alternative to reduce costs in the formulation of the fermentation medium and contributing to the integration of this bioprocess in a sugarcane biorefinery. Graphic
      PubDate: 2020-08-01
       
  • Exploitation of Agricultural Waste as Sole Substrate for Production of
           Bacterial l -Glutaminase Under Submerged Fermentation and the Proficient
           Application of Fermented Hydrolysate as Growth Promoting Agent for
           Probiotic Organisms
    • Abstract: Microbial l-glutaminase has diverse applications, ranging from food flavouring agent to treatment of cancer. Extracellular l-glutaminase producing one soil bacterium was characterized as Acinetobacter calcoaceticus PJB1 and was grown under submerged fermentation using sugarcane bagasse as sole supporting substrate. The optimum l-glutaminase production was achieved at initial medium pH of 10.0, incubation temperature at 35 °C, inoculums concentration of 1.5% (v/v) and at 72 h. Further improvement of the enzyme production was carried out by statistical optimization procedure using response surface methodology as a result of which enzyme production was enhanced to 47.95 U/ml (2.38-fold improvement). The enzymatic degradation pattern of sugarcane bagasse was appraised using Fourier transform infrared spectroscopy and light microscope. The fermented hydrolysate was proved to be a very effective growth inducer of probiotic organism as reflected by the higher specific growth rate, volumetric growth rate and overall yield of Lactobacillus sp. and Bifidobacterium sp. This study highlights the cost effective production of l-glutaminase and simultaneous utilization of fermented waste product as growth supporting agent for health beneficial probiotic organisms. Graphic
      PubDate: 2020-08-01
       
  • An Alkaline Glycine-Based Leach Process of Base and Precious Metals from
           Powdered Waste Printed Circuit Boards
    • Abstract: Electronic waste (E-waste) is accumulating rapidly globally and pose a significant environmental challenge. One of the ways to cover the cost of waste processing (in addition to reducing the costs associated with landfill) is through recovery of metals. In addition, toxic and dangerous metals can and must be removed prior to repurposing, incineration or pyrolysis of the plastic substrates. E-waste is usually either transported to landfills or processed by pyrometallurgical and hydrometallurgical processes. Recently, a number of hydrometallurgical approaches have been considered in metals recovery from different electronic components. In this study, glycine (amino acetic acid) or its salts is considered as a lixiviant in an alkaline environment for base and precious metals recovery from shredded and ground printed circuit boards (PCBs). It was found that alkaline glycine solutions selectively dissolve copper, zinc, and lead over precious metals. Gold and silver were then recovered in a subsequent leaching step using glycine and small amounts of cyanide (at starvation levels, implying no free cyanide is present). The leach system remains alkaline throughout both stages of processing. In the two-stage glycine leaching system, gold, silver, zinc, lead and copper recoveries were 92.1%, 85.3%, 98.5%, 89.8%, and 99.1% respectively. The recoveries of precious and base metals by direct cyanidation, single stage glycine–cyanide leaching, and ammonia leaching were lower than the recoveries of these metals using the two-stage glycine and glycine–cyanide systems. Graphic Flowsheet of a two-stage glycine leaching method for metal extractions from waste PCBs proposed in this study
      PubDate: 2020-08-01
       
  • Olive Pomace Oil can be Used as an Alternative Carbon Source for
           Clavulanic Acid Production by Streptomyces clavuligerus
    • Abstract: Clavulanic acid is an important drug, both medically and economically. It is used to combat bacterial resistance to β-lactam antibiotics and is on the World Health Organisation’s List of Essential Medicines in combination with amoxicillin. An olive oil industry waste product, olive pomace oil (OPO), is a potential alternative carbon source for clavulanic acid production by Streptomyces clavuligerus. OPO is six times cheaper than glycerol, which is the current industry standard. The aims of this study were to examine if OPO can be used as a carbon source for clavulanic acid production and to compare the clavulanic acid yield achieved in shake flasks and 1.8 L bioreactors. It was observed that OPO was efficiently utilised as a sole carbon source by S. clavuligerus growing in a P-limited medium. The S. clavuligerus cells grew faster in OPO-containing cultures compared to the glycerol-containing cultures (control) and produced comparable levels of clavulanic acid, but much earlier. In cultures with ISP2 medium that contained glycerol or OPO, higher levels of clavulanic acid were obtained in shake flask cultures with OPO. Interestingly, the same levels of clavulanic acid were observed in oil-containing cultures in bioreactors, but 48 h earlier. Furthermore, the oil-containing cultures did not need addition of an antifoam agent, while higher levels of cell viability were maintained after 72 h in these fermentations compared to the cultures that contained glycerol. Our results suggest that OPO can replace glycerol for clavulanic acid production in S. clavuligerus fermentations, which will significantly increase the productivity and cut the cost for industrial clavulanic acid biosynthesis. The same carbon source can be tested in other similar fermentation approaches for the production of antibiotics or other valuable bioproducts. Graphical
      PubDate: 2020-08-01
       
  • Value Addition of Waste Cotton: Effect of Nanofibrillated Cellulose on
           EVA/EVOH Toughened Polylactic Acid System
    • Abstract: The development of bionanocomposites is a promising approach in the current scenario with the urge to maintain environmental sustainability. The present study investigates the effect of nanocellulose on different properties of EVA/EVOH toughened Polylactic acid (PLA). Nanocellulose was isolated from waste cotton via an environmental friendly technique called steam explosion. Nanocellulose filled toughened PLA was prepared via melt mixing technique using twin screw extruder followed by injection molding. Prepared bionanocomposites were characterised by scanning electron microscopy, transmission electron microscopy, differential scanning calorimetry, thermogravimetric analysis etc. The addition of nanofibrillated cellulose up to 2 wt% retained the tensile strength of PLA/EVA/EVOH ternary blend systems whereas further weight loadings decreased the tensile strength significantly. Also, the addition of nanocellulose up to 2 wt% loading increased the modulus compared to PLA. The addition of nanofibrillated cellulose increased the stiffness of the composite. The percentage elongation at break showed 214% increase in the case of PLA/EVA/EVOH/NC 2 system in comparison to virgin PLA due to the plasticisation effect of EVA/EVOH together with the strong interactions of hydroxyl groups of nanocellulose. The impact strength was increased up to 89% by the addition of 2 wt% of nanocellulose. DSC studies revealed that the crystallization temperature decreased by the addition of nanocellulose up to 2 wt% in PLA matrix. This means that the nanocellulose acted as a nucleating agent such that it initiates crystallization phenomenon at a lower Tcc. The prepared bionanocomposite holds significant potential for sustainable PLA based packaging solutions. Graphic
      PubDate: 2020-08-01
       
  • Testing the Waste Based Biorefinery Concept: Pilot Scale Cultivation of
           Microalgal Species on Spent Anaerobic Digestate Fluids
    • Abstract: Purpose A waste based biorefinery approach has been tested. Methods This has been investigated by culturing in a 800 L photobioreactor two autotrophic microalgae namely Nannochloropsis oceanica and Scenedesmus quadricauda utilising filtered spent anaerobic digestate fluids of N:P ratio 14.22 as substrate. Results Significant rates of bioremediation simultaneously with biomass and associated end product formation were achieved. Nitrogen and phosphorus of waste based media was decreased up to 90%. The biomass biochemical analysis of the microalgae when grown on the waste based formulated media demonstrated the comparable content of lipids and proteins with the species grown on f/2 media. Conclusions Theoretical biomethane potential generation, should the algal cultures be placed in an anaerobic digester, was calculated at 0.58 L CH4 g−1 VS for N. oceanica and 0.48 L CH4 g−1 VS for S. quadricauda showing comparable results with other studies of different source of biomass. Graphic
      PubDate: 2020-08-01
       
  • Beneficiation of Sugarcane Bagasse Ash: Pozzolanic Activity and Leaching
           Behavior
    • Abstract: The annual production of sugarcane in Brazil is estimated at around 646 million tons and contributes around $US 43.8 billion of gross domestic product. Around 80% of Brazil’s biomass electricity is generated from sugarcane bagasse. However, the process of generating energy from bagasse using calcination leads to a by-product residue, sugarcane bagasse ash (SCBA), which requires disposal. A simple beneficiation protocol for sugarcane bagasse ash (SCBA) consisting of adequate calcination, grinding and density separation was explored in this study. SCBA was collected from industrial boilers in Brazil and treated to produce three different ashes, including the original untreated ash and two ashes collected from the top and bottom of a water-washing density separation process. Portland cement pastes incorporating 20% SCBA partial replacement for cement were made. Upon controlled burning and grinding, electrical conductivity and Chapelle tests indicated that SCBA had significant pozzolanic activity, with the top separated ash yielding best results. Mercury intrusion porosimetry showed that SCBA cement pastes had more refined porosity compared to that of the control paste. Fine SCBA particles ensured heterogeneous nucleation and promoted pore size refinement. Inductive coupled plasma testing indicated low levels of heavy metals leaching. Results demonstrate that SCBA can be beneficiated to provide an effective pozzolanic material, without harmful leachates released to the environment. Graphic
      PubDate: 2020-08-01
       
  • Preparation of Sodium Silicate Solutions and Silica Nanoparticles from
           South African Coal Fly Ash
    • Abstract: The production of amorphous mesoporous silica nanoparticles can be achieved using sodium silicate (Na2SiO3) solutions prepared from South African coal fly ash waste. The first part of this study compared two processes for the preparation of Na2SiO3 solutions. The first process, hereafter called sequential acid-alkaline leaching (SAAL), is a two-stage process, which involves (i) a H2SO4 leaching step for the preferential extraction of reactive aluminium over silicon, followed by (ii) the preferential extraction of silicon over aluminium from the resulting residues using NaOH. The second process is a direct alkaline leaching (DAL) process, which consists of a single-stage elemental extraction from ash using NaOH, i.e. without the preceding acid leaching step used in SAAL. The two processes generated Na2SiO3 solutions with identical pH (11.8), similar silicon (10.2–10.3 g/L), iron (ca. 200 mg/L) and potassium (ca. 800 mg/L) content, and low calcium concentrations (≤ 29 mg/L). However, the inclusion of the acid leaching step in the SAAL process yielded a Na2SiO3 solution with significantly lower aluminium content (166 mg/L vs. 1158 mg/L). The Na2SiO3 solutions obtained from the SAAL and DAL processes were then used as silica precursors to synthesise silica nanoparticles via a sol–gel method using polyethylene glycol (PEG) as surfactant and sulphuric acid as catalyst. All samples of synthesised silica nanoparticles were characterised by a high level of purity (up to 99.3 wt % SiO2). The insight gained is now being used to improve existing processes for the production of high-grade ultra-pure silica nanoparticles (i.e. ≥ 99.9 wt % SiO2) for catalyst support applications. Graphic
      PubDate: 2020-08-01
       
  • Investigation of Fiber Surface Treatment Effect on Thermal, Mechanical
           and Acoustical Properties of Date Palm Fiber-Reinforced Cementitious
           Composites
    • Abstract: High energy consumption in the building sector appeals for the implementation and the improvement of innovative approaches with low-environmental impact. The development of eco-friendly composites as insulating materials in buildings provides practical solutions for reducing energy consumption. Different mass proportions (2.5%, 10%, and 20%) of untreated and chemically treated palm fibers were mixed with (cement, water and sand) so as to prepare novel composites. Composites were characterized by measuring water absorption, thermal conductivity, compressive strength and acoustic transmission. The results reveal that the incorporation of untreated and chemically treated date palm fibers reduces novel composites’ thermal conductivity and the mechanical resistance. Thermal measurements have proved that the loading of fibers in composites decreases the thermal conductivity from 1.38 W m−1 K−1 for the reference material to 0.31 W m−1 K−1 for composites with 5% of treated and untreated fibers. The acoustical insulation capacity of untreated palm fiber-reinforced composites (DPF) was the highest at 20% fiber content, whereas treated palm fiber-reinforced composites (TPF) had the highest sound insulation coefficient for fiber content lower than 10%. Compressive strength, thermal conductivity and density correlation showed that only chemically treated fiber-reinforced composites (TPF) are good candidates for thermal and acoustic building insulations. Graphic
      PubDate: 2020-08-01
       
  • Influence of Neutralizing Agents on the Recovery of Ethanol from Banana
           Pseudostem Broth by Pervaporation
    • Abstract: Banana pseudostem is a potential source of lignocellulosic biomass for energy production. Ethanol production from this feedstock is characterized by pre-treatment, hydrolysis, fermentation and ethanol separation. When acid hydrolysis is carried out, a neutralizing step is necessary. This work aims to evaluate different neutralizing agents—barium carbonate, sodium hydroxide, calcium hydroxide, calcium sulfate, and sodium sulfate—and their effect on the ethanol recovery phase by pervaporation. Pervaporation experiments were conducted with a commercial flat-sheet polydimethylsiloxane membrane using a synthetic mixture of ethanol, water, and the residual neutralizing agent as feed. The experiments were compared to a standard solution (ethanol/water) to determine differences in the results due to the presence of neutralizing agents. Membrane swelling with different neutralizing agents was also assessed. Barium carbonate showed the highest potentiality of use in the neutralization process of the hydrolyzed broth of banana pseudostem since it presented the highest ethanol concentration in the permeate (17%) and an increase of approximately 15% of selectivity and 11% of enrichment factor. The results proved that acid hydrolyzed broth of banana pseudostem with the addition of barium carbonate as a neutralizing agent is a potential candidate for ethanol production using pervaporation. Graphic
      PubDate: 2020-08-01
       
  • Chemical Characteristics of Ash Formed from the Combustion of Shoe
           Manufacturing Waste in a 2.5 MW th Circulating Fluidized Bed Combustor
    • Abstract: The ash formation behaviour and associated compositional characteristics of the combustion of shoe manufacturing waste (SMW) in a 2.5 MWth pilot-scale circulating fluidized bed combustor (CFBC) were investigated to better understand the combustion behaviour and to find effective management strategy for the disposal of the ash streams produced. The compositional characterisations for the ashes produced from the pilot demonstrations showed the presence of a variety of trace heavy metals both in the fly ash and bottom ash. A pronounced uneven partitioning behaviour was observed on the distribution of these heavy metals between the fly ash and bottom ash, and it was found that all the heavy metals except chromium were preferentially enriched in the fly ash, with the contents of lead and cadmium in the fly ash being over 11 and 6 times higher than in the bottom ash. Leaching tests demonstrated that the concentrations of most of the aforementioned metals present in the leachates from the fly ash and bottom ash could meet the permissible limits for landfill disposal but with lead as an exception with its concentration in the fly ash leachates being over 2 times higher than the limit. The total PCDD and PCDF contents both in the fly ash and bottom ash were also much below the legal limit. To further understand the ash behaviour, the slagging and fouling tendency during SMW combustion in the CFBC was examined by use of the characterisation of the ash mineralogy and the results indicated that the SMW ash likely had low tendencies for slagging and fouling. The best two valorization routes for the SMW bottom ash and fly ash were recommended, one being to use them to produce colloidal silica medium to obtain safe inert filler and the other being to use them as the raw materials in the cement industry. Graphic
      PubDate: 2020-08-01
       
  • Seed-Assisted, OSDA-Free, Solvent-Free Synthesis of ZSM-5 Zeolite from
           Iron Ore Tailings
    • Abstract: Comprehensive utilization of iron ore tailings (IOT) not only solves environmental problems but also creates huge economic benefits. Our approach is focused on reutilization of IOT by converting it to ZSM-5 zeolite. The solvent and organic structure-directing agents (OSDA) used in the hydrothermal synthesis of ZSM-5 zeolite are major obstacles to achieve the sustainable synthesis routes. Therefore, the development of environmentally friendly ZSM-5 zeolite synthesis method is strongly desired. Here, ZSM-5 zeolite is synthesized successfully from IOT via a seed-assisted, solvent-free method without using the organic template or solvent. In addition, the influences of Na2CO3·10H2O/SiO2 molar ratio, amount of seeds, and crystallization process of ZSM-5 are systematically investigated. The raw materials and as-synthesized products are characterized by XRD, XRF, SEM, 27Al MAS NMR, and BET analysis; and the ZSM-5 zeolite synthesized by seed-assisted, OSDA-free, solvent-free method has the same mesoporous and microporous structure as the seed crystal. The synthetic route proposed in this work provides a novel green alternative for the synthesis of ZSM-5 from IOT. Graphic Figure schematic illustration of the seed-assisted, OSDA-free, solvent-free synthesis of ZSM-5 .
      PubDate: 2020-08-01
       
  • Effect of Coapplication of Biochar and Nutrients on Microbiocenotic
           Composition, Dehydrogenase Activity Index and Chemical Properties of Sandy
           Soil
    • Abstract: Biochar improves soil physical, chemical and biological properties. However, there is a very limited number of studies comparing the effect of various doses of biochar and wheat straw with nutrients on microbiocenotic composition of soil and their connection with selected biochemical and chemical parameters of soil. The aim of this study was to determine the effect of the addition to the soil of wheat straw (WS) and wheat straw biochar (WSB) (300 °C) at 0.2%, 0.5%, 1%, and 2% doses and the addition of nutrients (MF) on microbial community composition (bacteria, fungi, actinobacteria, Azotobacter spp., ammonifiers, nitrifiers, denitrifiers, C. pasteurianum), dehydrogenase activity index, carbon and nitrogen fractions contents and the content of water soluble Cu, Cd, Zn, and Pb. It was demonstrated that coapplication of WS and WSB with MF at 1% and 2% doses increased carbon and nitrogen contents in soil and, in particular, their water soluble fractions (DOC and DON). The synergistic effect of biochar and MF contributed to the increase in the population of soil microorganisms. Dehydrogenase activity index in treatments with the addition of WS, WSB and MF was 1.6–4 times higher compared to the control. The content of heavy metals significantly (p ≤ 0.05) affected dehydrogenase activity and the number of nitrifiers and ammonifiers. It was demonstrated that the content of C and N measured for soil microbial biomass in treatments amended with biochar and MF was much greater than in control treatment and MF. However, our studies suggest that the microorganisms’ response to the addition of biochar with nutrients increased the number and intensified the activity of soil microorganisms. Graphic
      PubDate: 2020-08-01
       
  • Amendment of Vermicompost by Phosphate Rock, Steel Dust, and
           Halothiobacillus neapolitanus
    • Abstract: The aim of the present study was to improve the nutrient content of vermicompost (VC) and make it a more suitable alternative to chemical fertilizers. VC samples were inoculated with Halothiobacillus neapolitanus and were subsequently amended with 5% mineral sulfur or left untreated as control. Both groups were supplemented with 5% or 10% of phosphate rock (PR) powder or steel dust at the final concentrations of 2.5% or 5%. Changes in pH, electrical conductivity (EC), phosphorous (P) and iron (Fe) contents of VC samples were monitored in a 60-day post-treatment period, in 20-day intervals. The sulfur containing samples, when compared with the untreated control, showed significant decrease in pH, which fell within the range of 4.6–5. The maximum EC values were observed in samples containing 5% sulfur with the highest amount of PR (S5P10) or steel dust but it did not exceed 3 dS m−1. A significant increase of 130% in P content was observed in the S5P10 sample and the highest concentration of Fe, 45%, was measured in the S5Fe5 sample after 40 days of incubation which was followed by a slight reduction. H. neapolitanus can provide a condition for solubilization of P and Fe from PR and steel dust, respectively, to improve the P and Fe content of VC. Graphic
      PubDate: 2020-08-01
       
  • Biodegradable Cassava Starch Based Foams Using Rice Husk Waste as Macro
           Filler
    • Abstract: Among the packages based on petroleum polymers, the use of the expanded polystyrene (EPS) which presents low production costs, low density, high resistance to humidity and dimensional stability, stands out. However, the improper disposal and difficulty of recycling them, together with their non-biodegradability can result in serious environmental problems. Knowing that there is no way to inhibit the population from using this material, the present study aimed to produce ecofriendly foams based on cassava starch and rice husk (RH). When compared to EPS, materials developed with biopolymers have lower flexibility and higher water sensitivity. The addition of rice husk improved the mechanical properties and reduced density and water capacity absorption in comparison to foams made using only starch. Foams were obtained by a thermopressing process, and the influence of different RH proportions (0, 20, 40, and 60% (w/w)) was investigated. The greater the RH amount, the higher the density and the lower the water absorption capacity (WAC). The maximum tensile stress and tensile strain were negatively influenced by the addition of 60% (w/w) RH. Differently from the maximum flexural stress that was positively influenced. Additionally, sorption isotherms showed that the samples with 40 and 60% RH adsorbed less water when compared to the foam without the filler. The formulation with 60% RH was chosen to storage cherry tomatoes due to its higher maximum flexural stress and lower WAC, being considered a promising material. Graphic
      PubDate: 2020-08-01
       
  • The Potential of Freshwater Fish Viscus from Silver Carp
           Hypophthalmichthys molitrix for Trypsin Source
    • Abstract: Purpose Silver carp is widely cultured in China (the product reached 3.5 million ton per year), and approximately 20% of the non-edible viscera are discarded. Utilization of the viscera leads to a reduction in waste. Our previous study showed that silver carp produced two types of myosin isoforms, thermostable myosin in summer and unstable one in winter, for the adaptation of the environmental changes. Therefore, in this study, we purified trypsins from silver carp in summer and winter samples to investigate their thermostabilities. Methods Trypsins from summer and winter samples were purified by a series of chromatographies. The temperature dependence of trypsins was determined at pH 8.0 in the range of 20–80 °C, and the effect of temperature on the thermostability was determined by measuring the remaining activity after the incubation at pH 8.0 for 15 min in the range of 20–75 °C. Results From the summer sample, two trypsins (SSC-T1 and SSC-T2) were purified 63- and 72-fold with the yields of 24 and 21%, respectively, and a trypsin (WSC-T) was purified 81-fold with a yield of 40% from the winter sample. SSC-T1, SSC-T2 and WSC-T showed the same enzymatic characteristics, especially their optimum temperature (65 °C) and thermostability (stable below 63 °C in 15-min incubation) were similar to mammalian trypsins. Additionally, all were stable at 30 °C for 8 h in the presence of calcium-ion. Conclusion These data indicated the silver carp viscus has a potential for thermostable trypsin source all the year round. Graphic Thermostable characteristics of trypsins from viscera of freshwater fish including silver carp (Hypophthalmichthys molitrix).
      PubDate: 2020-08-01
       
  • Assessment of Composition Changes, Stability Degree and the Potential of
           Biogas Formation of Sewage Sludge Composts During Maturation Process
    • Abstract: The aim of this study was to assess the degree of stabilization of composted sewage sludge (SSC) during maturation using tests in aerobic and anaerobic conditions, determining the potential for biogas formation and its composition, as well as changes of mobile and bioavailable forms of metals in SSC after treatment. The samples were taken in the second phase of composting, during the maturation process. The biological stability of SSC samples was determined by detecting an incubation test (GS21) and respiration index (AT4). The potential for biogas formation and composition changes of SSC during maturation were analyzed. It was found that the chemical composition of the tested samples depended on the degree of their maturity. It was found that the both tested methods (AT4, GS21) of assessing the stability of waste are sufficient. Treatment under anaerobic conditions did not significantly change the composition of the samples, with the exception of total organic carbon (TOC). A high percentage of methane in biogas for samples at the beginning of the maturation process indicates a high content of biodegradable organic matter in SSC. In addition, the decrease of mobile and bioavailable forms of heavy metals percentage, during the SSC maturation, was found. In order to confirm the results of current study, a long-term field studies should be carried out on the effects of SSCs tested on soils and plants. Graphic
      PubDate: 2020-08-01
       
 
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