Showing papers on "Biodegradation published in 1983"
TL;DR: This article corrects the article on p. 1239 in vol.
Abstract: The transformation of mono- and dinitroaromatic compounds was measured in sewage effluent maintained under aerobic or anaerobic conditions. Most of the nitrobenzene, 3- and 4-nitrobenzoic acids, and 3- and 4-nitrotoluenes and much of the 1,2- and 1,3-dinitrobenzenes disappeared both in the presence and absence of oxygen. Under anaerobiosis, 2,6-dinitrotoluene and 3,5-dinitrobenzoic acid disappeared slowly, but no loss was evident in 28 days in aerated sewage. Aromatic amines did not accumulate during the aerobic decomposition of the mononitro compounds. They did appear in nonsterile, but not in sterile, sewage incubated aerobically with the dinitro compounds and anaerobically with all the chemicals. Analysis by gas chromatography and combined gas chromatography-mass spectrometry showed that aniline was formed from nitrobenzene, toluidine was formed from 3- and 4-nitrotoluenes, and aminobenzoic acid was formed from 3- and 4-nitrobenzoic acids under anaerobiosis, and that nitroaniline was formed from 1,2- and 1,3-dinitrobenzenes, aminonitrotoluene resulted from 2,6-dinitrotoluene, and aminonitrobenzoic acid was a product of 3,5-dinitrobenzoic acid under both conditions. The isomeric forms of the metabolites were not established. Aniline, 4-toluidine, and 4-aminobenzoic acid added to sewage disappeared from aerated nonsterile, but not from sterile, sewage or sewage in the absence of oxygen. 2-Nitroaniline, 2-amino-3-nitrotoluene, and 2-amino-5-nitrobenzoic acid added to sewage persisted for at least 60 days in aerobic or anaerobic conditions. Gas chromatographic and gas chromatographic-mass spectrometric analyses demonstrated that acetanilide and 2-methylquinoline were formed from aniline, 4-methylformanilide and 4-methylacetanilide were formed from 4-toluidine, 2-methylbenzimidazole was a product of 2-nitroaniline, and unidentified benzimidazoles were formed from 2-amino-3-nitrotoluene in the absence of oxygen, and that 2-nitroacetanilide and 2-methyl-6-nitroacetanilide were formed from 2-nitroaniline and 2-amino-3-nitrotoluene, respectively, in the presence or absence of oxygen. It is suggested that the transformations of widely used nitroaromatic compounds should be further studied because of the persistence and possible toxicity of products of their metabolism.
192 citations
TL;DR: In this article, a method for measuring the primary biodegradability of water soluble dyestuffs under anaerobic conditions was described. But this method was applied to only 22 dyes of commercial significance.
178 citations
TL;DR: Methanogenic enrichments capable of degrading polyethylene glycol and ethylene glycol were obtained from sewage sludge and were shown to best metabolize glycols close to the molecular weight of the substrate on which they were enriched.
Abstract: Methanogenic enrichments capable of degrading polyethylene glycol and ethylene glycol were obtained from sewage sludge. Ethanol, acetate, methane, and (in the case of polyethylene glycols) ethylene glycol were detected as products. The sequence of product formation suggested that the ethylene oxide unit [HO-(CH2-CH2-O-)xH] was dismutated to acetate and ethanol; ethanol was subsequently oxidized to acetate by a syntrophic association that produced methane. The rates of degradation for ethylene, diethylene, and polyethylene glycol with molecular weights of 400, 1,000, and 20,000, respectively, were inversely related to the number of ethylene oxide monomers per molecule and ranged from 0.84 to 0.13 mM ethylene oxide units degraded per h. The enrichments were shown to best metabolize glycols close to the molecular weight of the substrate on which they were enriched. The anaerobic degradation of polyethylene glycol (molecular weight, 20,000) may be important in the light of the general resistance of polyethylene glycols to aerobic degradation.
148 citations
144 citations
TL;DR: Evidence collected during the study indicated that more complete biodegradation probably was occurring, suggesting that PCP was subject to at least primary biodegrades.
143 citations
TL;DR: During adaptation to high loads of chlorophenols the initial meta- Cleavage activity was completely replaced by ortho-cleavage activity of type I and II and total degradation of the organic carbon was indicated by release of stoichiometric amounts of chloride and low content of dissolved organic carbon in the cell-free effluents.
Abstract: Synthetic sewage containing phenol, acetone, and alkanols plus 4-chlorophenol or a mixture of isomeric chlorophenols is completely degraded by a defined mixed culture with Pseudomonas sp. strain B13 as a chlorocatechol-dissimilating member of the community. Total degradation of the organic carbon was indicated by release of stoichiometric amounts of chloride and low content of dissolved organic carbon in the cell-free effluents. During adaptation to high loads of chlorophenols the initial meta-cleavage activity was completely replaced by ortho-cleavage activity of type I and II. In the fully acclimated culture, hybrid strains such as Alcaligenes sp. strain A7-2 were detected, which are more competitive than Pseudomonas sp. strain B13 with respect to chlorophenol degradation.
111 citations
TL;DR: In this paper, the authors used gas chromatography-mass spectrometry (GC-MS) to identify the stages of the degradation process of Australian crude oils and the approximate burial depths of the reservoirs at the times of biodegradation.
Abstract: Degradation of petroleum in reservoirs by microorganisms is a process which has affected the chemical composition of many Australian crude oils. Oils from the Carnarvon and Gippsland Basins are used as examples to illustrate how the various classes of hydrocarbons are depleted in sequential fashion during the biodegradation process. Depletion of normal and branched alkanes, which is evident from gas chromatography, indicates that a crude oil has been mildly biodegraded. More advanced levels of biodegradation can be assessed from biomarker data obtained using gas chromatography-mass spectrometry. As the biodegradation process progresses one observes a sequential loss of n-alkanes, branched alkanes, δC-16 bicyclic alkanes, steranes with biological configurations, and finally, hopanes are converted into 25-norhopanes. The chemical compositions of the Eaglehawk, Rankin, and Windalia crude oils from the Carnarvon Basin suggest that they all result from a complex series of episodes of accumulation and biodegradation in the reservoirs. By assessing the proportions of each of the classes of characteristic marker compounds, and using the established relationship between reservoir temperature (depth) and the stages of hydrocarbon alteration during biodegradation, the approximate burial depths of the reservoirs at the times of biodegradation have been inferred. Thus, where multiple accumulation and degradation episodes can be recognised, the accumulation history of the oil in a reservoir can be reconstructed.
101 citations
TL;DR: Questions have been raised about the reliability of biodegradability screening tests, and the ability of such tests to predict fate of compounds in the “real world” (Alexander 1981).
Abstract: Microbial degradation (biodegradation) of organic chemicals is generally recognized as an important removal mechanism in natural systems. For chemicals which reach the aquatic environment in significant quantities, estimates of biodegradability are key in assessing the overall hazard associated with the use of a particular chemical (Larson 1980). Estimates of biodegradability are often generated in the laboratory via biodegradability screening studies (Larson 1979). In screening studies, compounds are tested as sole carbon and energy sources at relatively high (mg/L) concentrations with a dilute synthetic salts solution as the test medium. Degradation is measured nonspecifically by following the amount of carbon dioxide produced or oxygen consumed during microbial metabolism, and soil or sewage are typically used as the source of degradative microorganisms. These experimental conditions do not accurately simulate natural aquatic environments, where chemical concentrations are low (μg/L) and a variety of nutrient conditions and microbial species exist. As a result, legitimate questions have been raised about the reliability of biodegradability screening tests, and the ability of such tests to predict fate of compounds in the “real world” (Alexander 1981).
66 citations
TL;DR: The ability to degrade the chlorine compounds could be transferred from one reactor to another by transferring the liquid but no degradation occurred before addition of solids in the reactor as mentioned in this paper, and the degradation of pentachlorophenol was most active when softwood bark was used as the solid material It was less active on unglazed pottery, and inactive on glass (beads or fibre), cellulosic fibre, clay and ion exchange resin.
60 citations
TL;DR: Egyptian soil samples were used to obtain the anaerobic enrichment cultures for this study and 14CO2 or [14C]lignin wood was used to investigate the release of labeled gaseous or soluble degradation products of lignin in microbial cultures.
Abstract: The existence of anaerobic biodegradation of lignin was examined in mixed microflora. Egyptian soil samples, in which rapid mineralization of organic matter takes place in the presence of an important anaerobic microflora, were used to obtain the anaerobic enrichment cultures for this study. Specifically, 14CO2 or [14C]lignin wood was used to investigate the release of labeled gaseous or soluble degradation products of lignin in microbial cultures. No conversion of 14C-labeled lignin to 14CO2 or 14CH4 was observed after 6 months of incubation at 30 degrees C in anaerobic conditions with or without NO3-. A small increase in soluble radioactivity was observed in certain cultures, but it could not be related to the release of catabolic products during the anaerobic biodegradation of lignin.
1 Jan 1983
TL;DR: Frequent, repeated applications of phenoxyalkanoate, halogenated aliphatic, phenylcarbamate, and other pesticides are known to result in enhanced rates of biodegradation of these pesticides in soils, and some pesticides which may or may not inhibit microorganisms or enzymes responsible for degrading other pesticides, may actually act as inducers of microorganisms and/or enzymes which degrade other pesticides.
Abstract: Biodegradation is a critical factor affecting the persistence of most pesticides applied to soil. In addition to being affected by soil chemical and physical characteristics, the biodegradation processes associated with a given pesticide can also be influenced by the rate and frequency of its application, the rhizosphere effect, and the presence of other pesticides applied either simultaneously or sequentially. These interactions may result in either enhanced or reduced rates of pesticide biodegradation which may or may not be accompanied by concomitant changes in the soil microbial populations. Frequent, repeated applications of phenoxyalkanoate, halogenated aliphatic, phenylcarbamate, and other pesticides are known to result in enhanced rates of biodegradation of these pesticides in soils. Biodegradation of these chemicals is generally accompanied by an increase in numbers of specific pesticide degrading microorganisms. Certain methylcarbamate and organophosphate insecticides inhibit the enzymatic hydrolysis of numerous thio- and phenylcarbamates, acylanilides, and acetamide type herbicides by soil microorganisms, thus increasing their persistence in soil. The deliberate combination of such materials for purposes of controlled degradation and persistence of biodegradable pesticides has been investigated, and is now used in pesticide formulation technology. Recent investigations have also clearly demonstrated that some pesticides which may or may not inhibit microorganisms or enzymes responsible for degrading other pesticides, may actually act as inducers of microorganisms and/or enzymes which degrade other pesticides, even though they themselves are not necessarily substrates for the microbe or enzyme induced. The possible importance of this phenomenon in cropping systems treated with a variety of chemically analogous pesticides is currently under intensive investigation.
TL;DR: In this paper, the biodegradation of DTDMAC (ditallowdimethylammonium chloride, a fabric softening agent) was established in semi-batch activated sludge reactors.
TL;DR: A continuous flow soil respirometer was used to evaluate the effect of nutrient addition, application rate, and application frequency on biodegradation of 2 complex oily sludges in soil, indicating that repeated applications of smaller amounts of sludge result in a more rapid rate of decomposition.
Abstract: A continuous flow soil respirometer was used to evaluate the effect of nutrient addition, application rate, and application frequency on biodegradation of 2 complex oily sludges in soil. The most rapid biodegradation of the refinery sludge occurred when nitrogen was added to reduce the carbon to nitrogen (C∶N) ratio to 9∶1. The petrochemical sludge was degraded most rapidly when nitrogen, phosphorus, and potassium were added at a rate of 124∶1, C∶NPK; CO2evolution from both wastes increased with increasing application rates, but the fraction of applied sludge which degraded decreased with increasing application rates. Small frequent applications resulted in a slight increase in respiration rate per unit applied over a single equivalent application, indicating that repeated applications of smaller amounts of sludge result in a more rapid rate of decomposition. The population of total soil bacteria was greatest when 1% of either sludge was added to the soil, whereas 5 and 10% sludge additions resulted in slightly lower microbial populations.
Journal Article•
1 Feb 1983
TL;DR: In this paper, a new approach has been devised to try to render this enhancement process operational, and a nutrient including nitrogen, phosphorus and carbon has been developed and formulated as an oleophilic micro-emulsion.
Abstract: Biodegradation of oil is a natural and universal process. Unfortunately, it is a slow one, and most attempts to enhance it have failed. A new approach has been devised to try to render this enhancement process operational. A nutrient including nitrogen, phosphorus and carbon has been developed and formulated as an oleophilic micro-emulsion. It is, therefore, not dispersed in seawater. The nutrient has been tested in laboratory and field situations in temperate and cold climates. Biodegradation rates have ranged from 60 percent to 85 percent depending on conditions. Combined with natural evaporation, enhanced oil biodegradation can lead to a reduction in oil content of at least 65 percent in less than one week.
1 Sep 1983
TL;DR: In this paper, the authors describe the aerobic biodegradation of some non-ionic dispersants of the Span, Tween, and Corexit series in sea-water, where they are now more frequently found as a result of their application to the removal of oil spills.
Abstract: In this paper, we describe the aerobic biodegradation of some non-ionic dispersants of the Span, Tween, and Corexit series in sea-water, where they are now more frequently found as a result of their application to the removal of oil spills. First, the extent to which dispersants are biodegraded, as an indication of their suitability for use on a large scale, is discussed. Biodegradation may be carried out by means of monocultures or mixed cultures of marine bacteria of the genera Aeromonas, Pseudomonas, and Flavobacterium. Analytical techniques based on absorbance measurements were used to follow the process. On the other hand, by determining the kinetics of the biodegradation process a more complete analysis is obtained. The kinetic coefficients controlling the process are deduced and it is shown that for some dispersants the experimental results are in close agreement with the proposed scheme. Where observed values are explained on the basis of ethylene oxides content of the dispersants, estimations of the amount of dispersant present in the sea at a given time can be made, if the amount of the dispersant first used is known.
TL;DR: The synthesis confirms the feasibility of isotope labelling for biodegradation studies on mixtures of oligomers of 1-oetene and related compounds which have been proposed as dielectric fluids for the replacement of PCB's.
Abstract: The hydrocarbons 7-methylpentadecane (1, n = 0) and 7-methyl-9-n-hexyl heptadecane (1, n = 1) have been synthesized. These compounds arc suitable as model compounds for biodegradation studies on mi...
TL;DR: In this paper, a kinetic model was developed for stimulating DO and BOD concentration changes after a waste water discharge at temperatures ranging between 15 and 30°C, using cell ATP as biomass indicator, and the latter phase correspond to a cell division step.
TL;DR: In this paper, the oxygen dynamics and heterotrophic activities of a waste treatment system, consisting of a storage pond, a high rate algal pond (HRAP) and a fish pond, which handles the effluent from a cattle feedlot are presented.
1 Jan 1983
TL;DR: In this article, the most important factors controlling the biodegradability of synthetic polymers are the presence of hydrolyzable functional groups and accessibility of enzymes to the polymer chains.
Abstract: Natural macromolecules such as proteins, cellulose, and starch are generally degraded in biological systems by hydrolysis followed by oxidation. Our studies on the biodegradation of synthetic polymers suggested that the most important factors controlling the biodegradability of synthetic polymers are the presence of hydrolyzable functional groups and accessibility of enzymes to the polymer chains.1–4 Polymers with carbon backbones without any hydrolyzable linkage are thus less likely to be biodegradable. Indeed very few carbon chain polymers have been reported to be biodegradable. Among these is poly(vinyl alcohol), PVA. Casey and Manly used activated sludge to treat PVA textile waste water and Suzuki suggested that oxidation of PVA was the first stage of the microbial degradation of PVA.6 We reasoned that chemical oxidation of PVA should improve its biodegradability. Controlled chemical oxidation of the β-dihydroxy units in PVA should result in the generation of β-diketone ← → enol-ketone units, Fig. 1. Since β-diketones (enol-ketohes) are well known to form chelates with metal ions the poly(enol-ketone), PEK, derived from the controlled oxidation of PVA can be expected to coordinate strongly with metal ions. Application of PEK as a degradable metal ion removal agent can be anticipated.
1 Nov 1983
TL;DR: In this paper, a model fuel mixture of fifteen hydrocarbons representative of those in distillate jet fuels was used to determine whether degradation by natural microbial communities could affect the persistence of such fuels released into aquatic environments.
Abstract: : A model fuel mixture of fifteen hydrocarbons representative of those in distillate jet fuels was used to determine whether degradation by natural microbial communities could affect the persistence of such fuels released into aquatic environments. The mixture included hexane, cyclohexane, n-heptane, methylcyclohexane, toluene, n-octane, ethylcyclohexane, p-xylene, cumene, 1,3,5-trimethylbenzene, indan, naphthalene, 2-methylnaphthalene, n-tetradecane, and 2,3-dimethylnaphthalene. The water-soluble fraction of the model fuel was incubated in shake flasks with water or water and sediment suspensions collected at estuarine and freshwater sites, Surface films of the model mixture were studied under quiescent incubation. The disappearance of hydrocarbons was measured by capillary gas chromatography. Control flasks were sterilized with HgC1 to estimate losses due to abiotic processes. Fate tests were repeated with petroleum-derived JP-4. The soluble components of JP-4 were volatilized too rapidly for biodegradation to occur. Sedimentation dramatically affected the fate of fuel components when mixing of the hydrocarbon and sediment layers was studied. Sediment-associated components were more resistant to volatilization and microbial attack.
11 Apr 1983
Journal Article•
TL;DR: Investigation of a mixed culture of Scenedesmus obliquus, Chlorella vulgaris and Oscillatoria sp.
Abstract: The objective of this study was to investigate the influence of various octane concentrations on a mixed culture of Scenedesmus obliquus, Chlorella vulgaris and Oscillatoria sp. and the ability of these algae to utilize octane as the sole source of organic carbon in the medium. The same investigations were carried out for a mixed culture consisting of algae and the strain Acinetobacter calcoaceticus, and for A. calcoaceticus alone. The results obtained show that all of the strains under study, both algal and bacterial, can grow even at high octane concentrations and that they are able to utilize octane.
TL;DR: This article investigated the conditions necessary to preserve samples of biotreater clarifier effluent and mixed liquor suspended solids (MLSS), and concluded that refrigeration alone was not adequate to prevent primary degradation of the surfactant.