Search results for "Biodegradation"
showing 10 items of 317 documents
Hydrogen peroxide as a biodegradation stimulator in remediation processes of soils heavily contaminated with petrochemicals
2015
Abstract The soil contaminated with petroleum products must be excluded from the crops and treated to reclamation processes. Natural processes of decomposition of hydrocarbon compounds go very slow, so it is necessary to use bioaugumentation or stimulation in order to accelerate the return of the soil to high culture. In this study the effect of hydrogen peroxide on the process of cleaning soil strongly contaminated with pertochemicals was investigated. For this purpose, a pot experiment lasting 60 days was carried. The dynamics of changes in the population of filamentous fungi, yeasts and bacteria were examined and also content of aliphatic hydrocarbons (n-alkanes), monoaromatic and polycy…
Characterisation and Anaerobic Batch Degradation of Materials Accumulating in Anaerobic Digesters Treating Poultry Slaughterhouse Waste
2001
We characterised materials accumulating in two failed mesophilic semi-continuous anaerobic digesters treating poultry slaughterhouse waste and, for reference, materials in the two well-performing digesters, to find the anaerobic degradability of these materials and the factors affecting their degradation. We also studied materials accumulating and stratifying in various layers in one of the two well-performing digesters. The material from the most severely failed digesters produced methane sluggishly and did not improve appreciably even with 33 percent dilution suggesting that the recovery of failed process is slow. The methane production was apparently affected by the accumulated long-chai…
Sulphate-Reducing Laboratory-Scale High-Rate Anaerobic Reactors for Treatment of Metal- and Sulphate-Containing Mine Wastewater
2002
Upflow anaerobic sludge blanket (UASB) reactors were used in this study to evaluate the feasibility of the sulphate-reducing, anaerobic high-rate process to treat metal- and sulphate-containing mining wastewater (MWW). Four simultaneous reactors, inoculated with different inocula (mesophilic granular sludge from two UASB reactors, one treating sugar refinery wastewater and the other board mill wastewater) and operated with different loadings, were for 95 days fed with synthetic feed consisting of glucose and sulphate. In all reactors, 23-72% of sulphate and 12-93% of COD were removed. Subsequently, two reactors were fed with diluted MWW (zinc as the main metal) for 77 days with hydraulic re…
Genome Sequence of Rhodococcus sp. Strain BCP1, a Biodegrader of Alkanes and Chlorinated Compounds
2013
Rhodococcus sp. strain BCP1 (DSM 44980) co-metabolizes chlorinated compounds and mineralizes a broad range of alkanes being highly tolerant to these toxic chemicals. Here, we present the high-quality draft genome sequence of strain BCP1 consisting of 6,231,823 bp, with a G+C content of 70.4%, 5,902 protein-coding genes, and 58 RNAs genes. Rhodococcus genus comprises Gram-positive, non-sporulating, aerobic bacteria that are widely distributed in the environment (1). Rhodococcus sp. strain BCP1 (formerly: Rhodococcus aetherovorans strain BCP1, DSM 44980) was selected from an aerobic butane-utilizing consortium as the prevailing isolate able to co-metabolize chloroform, vinyl chloride and tric…
Impact of distribution heterogeneity of microorganisms and 2,4-D on biodegradation processes in soil : experiment and modelling
2013
Impact of distribution heterogeneity of microorganisms and 2,4-D on biodegradation processes in soil : experiment and modelling. Conference on Pesticide Behaviour in Soils, Water and Air (York 2013)
Variability of pesticide mineralization in individual soil aggregates of millimeter size
2002
The aim of this study was to compare the 2,4-D mineralization in individual aggregates of millimeter size (3 size classes and 96 aggregates per size class). 14 CO 2 coming from the mineralization of 14 C ring-labeled 2,4-D and evolved by each aggregate incubated in microtiter plates was trapped with barium hydroxide on filters and measured using a Phosphorimager. We observed an important variability of mineralization in aggregates of each size class and in the different size classes of aggregates. The main factors responsible for these fluctuations could be a heterogeneous distribution of degrading microorganisms or of available carbon necessary for cometabolism.
Microbial aspects of atrazine biodegradation in relation to history of soil treatment
1999
Among 15 soils with different cropping practices, seven which had an history of repeated atrazine applications showed accelerated degradation of this herbicide. By contrast, grassland or agricultural soils with no recorded atrazine application, at least for the last three years, had a low degradation potential. No direct relation was found between the rate of atrazine mineralisation and the size of the microbial biomass. In adapted soils, the amounts of extractable residues were lowered and the very high percentages of radioactivity from [ring-14C]atrazine recovered as [14C]carbon dioxide demonstrated that N-dealkylation and deamidation were the only processes for micro-organisms to derive …
Monitoring of atrazine treatment on soil bacterial, fungal and atrazine-degrading communities by quantitative competitive PCR
2003
We report the development of quantitative competitive (QC) PCR assays for quantifying the 16S, 18S ribosomal and atzC genes in nucleic acids directly extracted from soil. QC-PCR assays were standardised, calibrated and evaluated with an experimental study aiming to evaluate the impact of atrazine application on soil microflora. Comparison of QC-PCR 16S and 18S results with those of soil microbial biomass showed that, following atrazine application, the microbial biomass was not affected and that the amount of 16S rDNA gene representing 'bacteria' increased transitorily, while the amount of 18S rDNA gene representing fungi decreased in soil. In addition, comparison of atzC QC-PCR results wit…
Degradation of 2,4‐D, 2,4‐Dichlorophenol, and 4‐Chlorophenol in Soil after Sorption on Humified and Nonhumified Organic Matter
1999
Soil organic matter (SOM) primarily governs sorption processes and therefore affects the availability of organic chemicals to degrading microorganisms. Transformations of 14 C-ring-labeled 2,4-dichlorophenoxyacetic acid (2,4-D); 2,4-dichlorophenol (2,4-DCP); and 4-chlorophenol (4-CP) sorbed on organic materials with increasing degrees of humification (wood, fresh straw, composted straw, ligain, and humic acid) and on a reference mineral sorbent (Al-oxide) were studied during soil incubation experiments. Chemicals previously sorbed on the different sorbents were applied to the soil. Mineralization kinetics, analysis of water and methanol extracts and measurements of the nonextractable radioa…
Isoproturon
2010
Frequent use of phenylurea herbicide isoproturon (IPU) in agricultural fields has resulted not only in the contamination of the natural resources including soil and water but also in the adaptation of the soil microflora to its rapid degradation. However, up to now, the mechanisms underlying this microbial adaptation are not well elucidated. The aim of this study was to explore the processes and factors implicated in IPU degradation from the agricultural field to the genes coding for catabolic genes. The study carried out at the experimental field of Epoisses cropped with a winter wheat / barley / rape seed crop rotation indicated that as a result of its periodically repeated use, the soil …