Search results for "Biodegradation"
showing 10 items of 317 documents
Biostimulation of in situ microbial degradation processes in organically-enriched sediments mitigates the impact of aquaculture
2019
Fish farm deposition, resulting in organic matter accumulation on bottom sediments, has been identified as among the main phenomena causing negative environmental impacts in aquaculture. An in situ bioremediation treatment was carried out in order to reduce the organic matter accumulation in the fish farm sediments by promoting the natural microbial biodegradation processes. To assess the effect of the treatment, the concentration of organic matter in the sediment and its microbial degradation, as well as the response of the benthic prokaryotic community, were investigated. The results showed a significant effect of the treatment in stimulating microbial degradation rates, and the consequen…
Occurrence of coal and coal-derived particle-bound polycyclic aromatic hydrocarbons (PAHs) in a river floodplain soil.
2006
A PAH contaminated river floodplain soil was separated according to grain size and density. Coal and coal-derived particles from coal mining, coal industry and coal transportation activities were identified by organic petrographic analysis in our samples. Distinct concentrations of PAHs were found in different grain size and density fractions, however, similar distribution patterns of PAHs indicated similar sources. In addition, although light fractions had the mass fraction by weight of less than 5%, they contributed almost 75% of the total PAHs in the soil. PAH concentrations of all sub fractions showed positive correlation with their TOC contents. Altogether, coal and coal-derived partic…
Bioaccumulation and subchronic physiological effects of waterborne iron overload on whitefish exposed in humic and nonhumic water.
1999
One-year-old whitefish, Coregonus lavaretus, were exposed to three types of iron-rich water, two dilutions for each, in a subchronic (30-day) experiment. In natural iron-rich humic water, both the bioaccumulation and physiological effects of iron exposure were negligible. In humic-free water with high amount of additional inorganic iron (nominally 8 mg Fe/L), Fe accumulated in gills, liver, and gut. This accumulation was accompanied by decreased glycogen phosphorylase activities and microsomal EROD activity in the liver as well as decreased plasma sodium and potassium concentrations. The third group of whitefish were exposed by adding inorganic iron (nominally 2 and 8 mg Fe/L) to natural ir…
Transmission to Eels, Portals of Entry, and Putative Reservoirs of Vibrio vulnificus Serovar E (Biotype 2)
2001
ABSTRACT Vibrio vulnificus serovar E (formerly biotype 2) is the etiologic agent that is responsible for the main infectious disease affecting farmed eels. Although the pathogen can theoretically use water as a vehicle for disease transmission, it has not been isolated from tank water during epizootics to date. In this work, the mode of transmission of the disease to healthy eels, the portals of entry of the pathogen into fish, and their putative reservoirs have been investigated by means of laboratory and field experiments. Results of the experiments of direct and indirect host-to-host transmission, patch contact challenges, and oral-anal intubations suggest that water is the prime vehicle…
New biodegradable hydrogels based on a photocrosslinkable modified polyaspartamide: synthesis and characterization
1999
Abstract α,β-Poly( N -2-hydroxyethyl)- dl -aspartamide (PHEA), a synthetic water-soluble biocompatible polymer, was derivatized with glycidyl methacrylate (GMA), in order to introduce in its structure chemical residues having double bonds and ester groups. The obtained copolymer (PHG) contained 29 mol% of GMA residues. PHG aqueous solutions at various concentrations ranging from 30 to 70 mg/ml were exposed to a source of UV rays at λ 254 nm in the presence or in the absence of N , N ′-methylenebisacrylamide (BIS); the formation of compact gel phases was observed beginning from 50 mg/ml. The obtained networks were characterized by FT-IR spectrophotometry and swelling measurements which evide…
New biodegradable hydrogels based on an acryloylated polyaspartamide cross-linked by gamma irradiation
1999
Alpha, beta-poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA), a synthetic biocompatible macromolecule, was functionalized with glycidyl methacrylate (GMA) in order to introduce in its side chains residues having double bonds and ester groups. The copolymer (PHG), obtained from PHEA and GMA, had a degree of derivatization of 29 mol%. PHG aqueous solutions are cross-linked by gamma radiation at 0 degrees C either in the presence or absence of N,N'-methylenebisacrylamide (BIS) giving rise to new hydrogel systems. In both cases gelation occurs at quite low doses (0.26 and 0.4 kGy, respectively). The obtained networks were characterized by FT-IR spectrophotometry which confirmed that the cross-linki…
Exploring long chain n-alkane metabolism in Gordonia sp. strain SoCg
2009
Many microorganisms are able to degrade aliphatic hydrocarbons and a relationship between n-alkane utilization and storage compound synthesis has been described in bacteria. The Gram positive GC-rich n-alkane degrader Gordonia sp. strain SoCg, isolated from a long-term accidentally contaminated beach in Sicily, is able to grow on long n-alkanes up to. It carries a single copy of the alkane hydroxylase gene alkB on its chromosome and its alk cluster revealed a genomic organization similar to other alk clusters of alkane-degrading Gram positive bacteria. The alk gene expression, analysed by Real-time RT-PCR, is induced by n-hexadecane and n-triacontane and coupled to alkane consumption. Inter…
Biotransformation and toxicity effect of monoanthraquinone dyes during Bjerkandera adusta CCBAS 930 cultures.
2020
Abstract The aim of this study was to evaluate of possibility of biotransformation and toxicity effect of monoanthraquinone dyes in cultures of Bjerkandera adusta CCBAS 930. Phenolic compounds, free radicals, phytotoxicity (Lepidium sativum L.), ecotoxicity (Vibrio fischeri) and cytotoxicity effect were evaluated to determine the toxicity of anthraquinone dyes before and after the treatment with B. adusta CCBAS 930. More than 80% of ABBB and AB129 was removed by biodegradation (decolorization) and biosorption, but biodegradation using oxidoreductases was the main dye removing mechanism. Secondary products toxic to plants and bacteria were formed in B. adusta strain CCBAS 930 cultures, despi…
Factors influencing structural heat-induced structural relaxation of dissolved organic matter
2018
Abstract Physical and chemical structure affect properties of dissolved organic matter (DOM). Recent observations revealed that heating and cooling cycles at higher temperature amplitude lead to a change in DOM physical conformation assumingly followed by a slow structural relaxation. In this study, changes at lower temperature amplitudes and their relation to DOM composition were investigated using simultaneous measurements of density and ultrasonic velocity in order to evaluate the adiabatic compressibility, which is sensitive indicator of DOM structural microelasticity. Six fulvic acids (FAs) having various origins were analyzed at concentrations of 0.12, 0.6 and 1.2 g L−1 and at differe…
The effects of woodchip- and straw-derived biochars on the persistence of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) in soils
2014
Sorption and degradation are the primary processes controlling the efficacy and runoff contamination risk of agrochemicals. This study assessed the influence of two biochars, made from woodchips and straw at a pyrolysis temperature of 725°C and applied to a loamy sand and a sandy soil in the concentration of 5.3 g 100 g(-1) sandy soil and 4.1 g 100 g(-1) loamy sand soil, or 53 t ha(-1) for both soil types, on degradation of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA). Soils were spiked with 50 mg MCPA kg(-1) soil. In the sandy soil, significantly more MCPA remained after 100 days if amended with straw-derived biochar in comparison to wood-derived biochar. Both biochars types si…