scholarly journals Decomposition of Organic Chemical Components in Wood by Tropical Xylaria Species

2020 ◽  
Vol 6 (4) ◽  
pp. 186
Author(s):  
Takashi Osono
Keyword(s):  
Mass Loss ◽  
Leaf Litter ◽  
Tree Species ◽  
Chemical Components ◽  
Organic Chemical ◽  
Klason Lignin ◽  
Wood Decomposition ◽  
Recalcitrant Compounds ◽  
Initial Content

The ability of Xylaria species obtained from tropical wood and leaf litter to cause a mass loss of lignin and carbohydrates in wood was examined in vitro with pure culture decomposition tests. The mass loss of wood of four tree species caused by nine Xylaria isolates ranged from 4.5% to 28.4% of the original wood mass. These Xylaria isolates have a potential ability to decompose lignin and other recalcitrant compounds, collectively registered as acid unhydrolyzable residues or Klason lignin in wood. The origin of isolates (i.e., isolates from wood versus leaf litter) did not affect the mass loss of acid unhydrolyzable residue in wood. The Xylaria isolates tested generally caused a selective decomposition of polymer carbohydrates in wood in preference to acid unhydrolyzable residue. The mass loss of acid unhydrolyzable residue caused by Xylaria isolates varied with the tree species of the wood and was negatively related to the initial content of acid unhydrolyzable residue in wood, implying the limiting effect of lignin and recalcitrant compounds on wood decomposition by Xylaria isolates.

Decomposition of needle litter and its organic chemical components: theory and field experiments. Long-term decomposition in a Scots pine forest. III

1984 ◽  
Vol 62 (12) ◽  
pp. 2880-2888 ◽  
Author(s):  
Björn Berg ◽  
Göran I. Ågren
Keyword(s):  
Chemical Composition ◽  
Mass Loss ◽  
Scots Pine ◽  
Field Experiments ◽  
Average Rate ◽  
Chemical Components ◽  
Organic Chemical ◽  
Labile Fraction ◽  
Lignin Fraction ◽  
Scots Pine Forest

Scots pine needles were collected and field incubations were begun in the autumn of 6 consecutive years. The incubated needles were sampled three times a year and analysed for mass loss and chemical composition. The longest incubation time obtained was 1825 days. Four series of needles from a nutrition experiment (three levels of nutrient application and one control) sampled at one occasion were followed in the same way for 1448 days. The logarithm of remaining mass versus time of the pooled samples fits a linear regression well (average rate constant = 0.286 year−1, r2 = 0.963, n = 75). A higher resolution shows, however, that the decay rate decreases with time as the chemical composition changes. To better understand the decomposition process we have formulated a mathematical model for the course of mass loss as a system consisting of two fractions, a readily decomposable (labile) one and a refractory one. The mass loss from the two fractions can be direct or mass can be transferred from the refractory to the labile fraction. The model allows us to calculate the variation of the refractory fraction with time (generally there will always be some labile material in the system) and the decrease of the decomposition rate as a function of time or as a function of the concentration of the refractory fraction. We have found it possible to identify the refractory fraction both as the lignin fraction and as the nonsoluble fraction of the needles. The first identification yields a long transient response, whereas the second gives a system rapidly reaching a steady state. In both cases, the decay of the refractory material results in transfer of material to the labile fraction.

scholarly journals Leaf Litter Decomposition and Nutrient Dynamics Associated with Common Horticultural Cropland Agroforest Tree Species of Bangladesh

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Md. Hasanuzzaman ◽  
Mahmood Hossain
Keyword(s):  
Mass Loss ◽  
Leaf Litter ◽  
Litter Decomposition ◽  
Tree Species ◽  
Decay Constant ◽  
Nutrient Dynamics ◽  
Mangifera Indica ◽  
Decomposition Process ◽  
Leaf Litter Decomposition ◽  
Zizyphus Jujuba

Mangifera indica,Zizyphus jujuba,Litchi chinensis, andArtocarpus heterophyllusare the most common cropland agroforest horticultural tree species of Bangladesh. This study focused on leaf litter decomposition and nutrient (N, P, and K) dynamics during the decomposition process. This experiment was conducted for 180 days by using litter bag technique during dry and wet seasons. Mass loss was the highest (49% and 57%) forA. heterophyllusand the lowest (25%) was found forL. chinensis. The highest initial rates (0.75% and 2.35%/day) of decomposition were observed forZ. jujubaand the lowest (0.50% and 0.79%/day) forL. chinensis. The highest decay constant was observed forA. heterophyllus(2.14 and 2.34) and the lowest (0.88 and 0.94) forL. chinensis. Leaf litter of all the studied species showed a similar pattern (K > N > P) of nutrient release during the decomposition process.Zizyphus jujubashowed comparatively higher return of N, P, and K than others. However, a significant (P<0.05) higher amount of mass loss, rate of decomposition, decay constant, and amount of nutrient return from leaf litter were observed during the wet season.

Tree species mediated effects on leaf litter dynamics in pure and mixed stands of oak and beech

2008 ◽  
Vol 38 (3) ◽  
pp. 528-538 ◽  
Author(s):  
Mathieu Jonard ◽  
Frederic Andre ◽  
Quentin Ponette
Keyword(s):  
Mass Loss ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Leaf Litter ◽  
Tree Species ◽  
Litter Quality ◽  
Leaf Decomposition ◽  
Mixed Stands ◽  
Stand Type

This study aimed to evaluate the relative importance of the factors whereby tree species composition can influence leaf litter dynamics. Leaf litter production and chemical composition were measured in pure and mixed stands of oak ( Quercus petraea Liebl.) and beech ( Fagus sylvatica L.). Pure and mixed leaf litter of both species were incubated in each stand type to assess separately the environmental, litter quality, and litter mixture effects on decomposition. To better understand the environmental effects, ground climate was measured in the different stands and the effects of soil water content on decomposition were evaluated using roofs to simulate drought conditions. Although total leaf litter amounts were not affected by stand composition, leaf decomposition varied with litter quality and with the environmental conditions. In the same environment, oak leaf litter disappeared on average 1.7 times faster than beech leaf litter. Decomposition of oak leaves increased significantly in the mixed-species litterbags. In contrast, the overall mass loss of the mixed litter tallied with the mass loss estimated by examining the decomposition of the component litter separately (additive-effect hypothesis). The effects of stand type appeared in the third year of incubation: leaf mass loss of both species was greater in the beech stand. In addition, soil water content affected leaf decomposition: the oak and beach leaf mass losses dropped by 24% and 17%, respectively, in the dry modality.

scholarly journals Bleaching of leaf litter accelerates the decomposition of recalcitrant components and mobilization of nitrogen in a subtropical forest

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Takashi Osono ◽  
Syuntaro Hiradate ◽  
Satoru Hobara
Keyword(s):  
Mass Loss ◽  
Leaf Litter ◽  
Dominant Role ◽  
Subtropical Forest ◽  
Decomposition Processes ◽  
Recalcitrant Compounds ◽  
Leaf Tissues ◽  
Field Incubation ◽  
Bleached Area ◽  
Rapid Mass

AbstractSelective removal of lignin and other recalcitrant compounds, collectively registered as acid-unhyrolyzable residue (AUR), results in bleaching of leaf litter, but the importance of bleaching in decomposition processes on forest soil has not been fully evaluated. The aims of this study were to elucidate the occurrence of bleached area in decomposing leaf litter and to compare chemical composition between bleached and nonbleached portions in a subtropical forest in Japan. Field incubation of leaf litter was performed over an 18-month period with the litterbag method. The decomposition processes during the first 9 month were characterized by the relatively rapid mass loss and increase of bleached area, whereas the mass loss was slowed down and the bleached area decreased thereafter. Mass loss of leaf tissues was faster and AUR content was lower in bleached than in nonbleached portions, indicating the acceleration of mass loss in bleached leaf tissues by the selective decomposition of recalcitrant compounds. The decrease in carbonyl-C in the bleached portions was associated with the increase of extractable nitrogen. The results suggest that the bleaching plays a dominant role in the transformation and turnover of organic compounds and nitrogen in decomposing leaf litter.

Ants accelerate litter decomposition in a Costa Rican lowland tropical rain forest

2012 ◽  
Vol 28 (5) ◽  
pp. 437-443 ◽  
Author(s):  
Terrence P. McGlynn ◽  
Evan K. Poirson
Keyword(s):  
Mass Loss ◽  
Leaf Litter ◽  
Litter Decomposition ◽  
Rain Forest ◽  
Costa Rican ◽  
Tropical Rain Forests ◽  
Rain Forests ◽  
Food Web Structure ◽  
Litter Bags ◽  
Lowland Rain Forest

Abstract:The decomposition of leaf litter is governed, in part, by litter invertebrates. In tropical rain forests, ants are dominant predators in the leaf litter and may alter litter decomposition through the action of a top-down control of food web structure. The role of ants in litter decomposition was investigated in a Costa Rican lowland rain forest with two experiments. In a mesocosm experiment, we manipulated ant presence in 50 ambient leaf-litter mesocosms. In a litterbag gradient experiment, Cecropia obtusifolia litter was used to measure decomposition rate constants across gradients in nutrients, ant density and richness, with 27 separate litterbag treatments for total arthropod exclusion or partial arthropod exclusion. After 2 mo, mass loss in mesocosms containing ants was 30.9%, significantly greater than the 23.5% mass loss in mesocosms without ants. In the litter bags with all arthropods excluded, decomposition was best accounted by the carbon: phosphorus content of soil (r2 = 0.41). In litter bags permitting smaller arthropods but excluding ants, decomposition was best explained by the local biomass of ants in the vicinity of the litter bags (r2 = 0.50). Once the microarthropod prey of ants are permitted to enter litterbags, the biomass of ants near the litterbags overtakes soil chemistry as the regulator of decomposition. In concert, these results support a working hypothesis that litter-dwelling ants are responsible for accelerating litter decomposition in lowland tropical rain forests.

Organic chemical devulcanization of rubber vulcanizates in supercritical carbon dioxide and associated less eco-unfriendly approaches: A review

2021 ◽  
pp. 0734242X2110085
Author(s):  
Jabulani I Gumede ◽  
Buyiswa G Hlangothi ◽  
Chris D Woolard ◽  
Shanganyane P Hlangothi
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Negative Impact ◽  
Raw Materials ◽  
Chemical Components ◽  
Organic Chemical ◽  
Attractive Alternative ◽  
Special Focus ◽  
Waste Tyres ◽  
Supercritical Carbon

There is a growing need to recover raw materials from waste due to increasing environmental concerns and the widely adopted transition to circular economy. For waste tyres, it is necessary to continuously develop methods and processes that can devulcanize rubber vulcanizates into rubber products with qualities and properties that can closely match those of the virgin rubber. Currently, the most common, due to its efficiency and perceived eco-friendliness in recovering raw rubber from waste rubbers, such as tyres, is devulcanization in supercritical carbon dioxide (scCO2) using commercial and typical devulcanizing agents. The scCO2 has been generally accepted as an attractive alternative to the traditional liquid-based devulcanization media because of the resultant devulcanized rubber has relatively better quality than other processes. For instance, when scCO2 is employed to recover rubber from waste tyres (e.g. truck tyres) and the recovered rubber is blended with virgin natural rubber (NR) in various compositions, the curing and mechanical properties of the blends closely match those of virgin NR. The atmospheric toxicity and cost of the commonly used devulcanization materials like chemical agents, oils and solvents have enabled a shift towards utilization of greener (mainly organic) and readily available devulcanization chemical components. This literature review paper discusses the approaches, which have less negative impact on the environment, in chemical devulcanization of rubber vulcanizates. A special focus has been on thermo-chemical devulcanization of waste tyres in scCO2 using common organic devulcanizing agents.

scholarly journals In vitro biological activity of Hydroclathrus clathratus and its use as an extracellular bioreductant for silver nanoparticle formation

2020 ◽  
Vol 9 (1) ◽  
pp. 416-428 ◽  
Author(s):  
Raghad R. Alzahrani ◽  
Manal M. Alkhulaifi ◽  
Nouf M. Al-Enazi
Keyword(s):  
Biological Activity ◽  
Unsaturated Fatty Acids ◽  
Multidrug Resistant ◽  
Chemical Components ◽  
Resistant Bacteria ◽  
Transmission Electron ◽  
Hydroclathrus Clathratus ◽  
Adaptive Nature ◽  
First Time

AbstractThe adaptive nature of algae results in producing unique chemical components that are gaining attention due to their efficiency in many fields and abundance. In this study, we screened the phytochemicals from the brown alga Hydroclathrus clathratus and tested its ability to produce silver nanoparticles (AgNPs) extracellularly for the first time. Lastly, we investigated its biological activity against a variety of bacteria. The biosynthesized nanoparticles were characterized by UV-visible spectroscopy, Fourier-transform infrared spectroscopy, dynamic light scattering, transmission electron microscopy, and energy-dispersive spectroscopy. The biological efficacy of AgNPs was tested against eighteen different bacteria, including seven multidrug-resistant bacteria. Phytochemical screening of the alga revealed the presence of saturated and unsaturated fatty acids, sugars, carboxylic acid derivatives, triterpenoids, steroids, and other components. Formed AgNPs were stable and ranged in size between 7 and 83 nm and presented a variety of shapes. Acinetobacter baumannii, Staphylococcus aureus, Methicillin-resistant S. aureus (MRSA), and MDR A. baumannii were the most affected among the bacteria. The biofilm formation and development assay presented a noteworthy activity against MRSA, with an inhibition percentage of 99%. Acknowledging the future of nano-antibiotics encourages scientists to explore and enhance their potency, notably if they were obtained using green, rapid, and efficient methods.

scholarly journals Noble Metals for Modern Implant Materials: MOCVD of Film Structures and Cytotoxical, Antibacterial, and Histological Studies

Biomedicines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 851
Author(s):  
Svetlana I. Dorovskikh ◽  
Evgeniia S. Vikulova ◽  
Elena V. Chepeleva ◽  
Maria B. Vasilieva ◽  
Dmitriy A. Nasimov ◽  
...  
Keyword(s):  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Noble Metals ◽  
Mononuclear Cells ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Ti Alloy ◽  
Peripheral Blood Mononuclear ◽  
Histological Studies

This work is aimed at developing the modification of the surface of medical implants with film materials based on noble metals in order to improve their biological characteristics. Gas-phase transportation methods were proposed to obtain such materials. To determine the effect of the material of the bottom layer of heterometallic structures, Ir, Pt, and PtIr coatings with a thickness of 1.4–1.5 μm were deposited by metal–organic chemical vapor deposition (MOCVD) on Ti6Al4V alloy discs. Two types of antibacterial components, namely, gold nanoparticles (AuNPs) and discontinuous Ag coatings, were deposited on the surface of these coatings. AuNPs (11–14 nm) were deposited by a pulsed MOCVD method, while Ag films (35–40 nm in thickness) were obtained by physical vapor deposition (PVD). The cytotoxic (24 h and 48 h, toward peripheral blood mononuclear cells (PBMCs)) and antibacterial (24 h) properties of monophase (Ag, Ir, Pt, and PtIr) and heterophase (Ag/Pt, Ag/Ir, Ag/PtIr, Au/Pt, Au/Ir, and Au/PtIr) film materials deposited on Ti-alloy samples were studied in vitro and compared with those of uncoated Ti-alloy samples. Studies of the cytokine production by PBMCs in response to incubation of the samples for 24 and 48 h and histological studies at 1 and 3 months after subcutaneous implantation in rats were also performed. Despite the comparable thickness of the fibrous capsule after 3 months, a faster completion of the active phase of encapsulation was observed for the coated implants compared to the Ti alloy analogs. For the Ag-containing samples, growth inhibition of S. epidermidis, S. aureus, Str. pyogenes, P. aeruginosa, and Ent. faecium was observed.

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