Abstract: The heterotrophic uptake technique was modified to provide a rapid and simple technique for estimating the rates of biodegradation of organic pollutants under environmental conditions. The methodology is based on an evaluation of uptake into cells and subsequent respiration of radiolabeled organic substrates in short-term experiments. The resulting data can be used to calculate either turnover times or, if multiple concentrations of substrate are used, kinetic parameters. The procedure was applied to assess the biodegradation rates of m-cresol, chlorobenzene, nitrilotriacetic acid, and 1,2,4-trichlorobenzene in fresh, brackish, and marine water samples from the coastal areas of North Carolina. Saturation kinetics for uptake were obtained with each of the compounds tested. Rates of metabolism were shown to be dependent on sample location and time of year.

Abstract: Soluble fragments of lignin origin obtained by thermochemical treatment of [14C]lignin-labeled lignocellulose served as substrate for anaerobic enrichment cultures. This study demonstrates that oli...

Abstract: The interaction of polymers with physiological environment on the cell level is discussed. A model polymer system with an easily variable structure has been suggested for a detailed study of these interactions, and of enzyme-controlled degradation in the first place. Water-soluble copolymers of N-(2-hydroxypropyl)methacrylamide containing oligopeptidic sequences both in side chains and in crosslinks connecting two synthetic polymer chains were synthesized. The relationship between the structure of such oligopeptidic sequences and their degradability by chymotrypsin, trypsin, papain, isolated intracellular enzymes, cell cultures and in vivo was examined. The possibility of using information thus obtained in a tailor-made preparation of polymeric carriers able to transfer the bound drug into specific cells is discussed.

Abstract: Biodegradation of 2,4-dichlorophenoxyacetate (2,4-D) and glucose were studied using a 2,4-D acclimated culture. Biodegradation of glucose by the 2,4-D preacclimated culture follows the typical Monod kinetics after a 20-h lag period in the presence or absence of 2,4-D. Biodegradation of 2,4-D by the same culture follows Andrew's "substrate inhibition" model. When both glucose and 2,4-D are available, mutual inhibition is observed. However, the effect on 2,4-D is masked by the fact that larger concentrations of active biomass are produced when glucose is available. This kind of concurrent utilization and interaction results in a substantial reduction of the mean cell residence time in a continuous flow system. It also extends the area of stability of the process into higher dilution rates as well as into higher influent concentrations.

Abstract: An estimated 65% of our biomass is produced on land. Of that biomass, lignin is the most abundant natural polymer next to cellulose and is an important renewable source of aromatic carbon on earth. Since lignin and cellulose, together with the hemicelluloses, are the structural components of the vascular tissues of higher land plants, biodegradation of the vascular tissues is the key process in the recycling of terrestrial biosynthetic carbon.

Abstract: The biodegradation of the surfactant sodium dodecyltriethoxy sulfate by Pseudomonas sp, strain DES1 (isolated from activated sludge plant effluent) has been studied Growth of the organism when the 35S-labeled surfactant was present as the sole source of carbon and energy led to the appearance in the culture fluid of five 35S-labeled organic metabolites These have been identified as mono-, di-, and triethylene glycol monosulfates (major metabolites) and acetic acid 2-(ethoxy sulfate) and acetic acid 2-(diethoxy sulfate), authentic samples of which have been prepared and characterized Evidence is presented that the major metabolites were produced by rupture of one or another of the three ether linkages present in the surfactant molecule, probably via the agency of a single etherase enzyme Acetic acid 2-(ethoxy sulfate) and acetic acid 2-(diethoxy sulfate) were formed by the oxidation of the free alcohol groups of di- and triethylene glycol monosulfates, respectively, and increased in amount during the stationary phase of growth Inorganic 35S-sulfate also appeared in significant quantities in culture fluids and arose from the parent surfactant (presumably via the action of an alkylsulfatase) and not from any of the five metabolites The appearance of sulfated organic metabolites during the exponential phase of growth and their quantitative relationship remained remarkably constant, even when additional carbon and energy sources (succinate or yeast extract) were also present in the growth media

Abstract: Natural mixed-microbial populations in lake water were found capable of oxidizing 2-chlorobiphenyl but not 2,4'-dichlorobiphenyl. No evidence was found to indicate that these populations were able to oxidize a PCB mixture 54% chlorine by weight. Oxidation of 2-chlorobiphenyl resulted in the accumulation of two biotransformation products, chlorobenzoic acid and chlorobenzoylformic acid (chlorophenylglyoxylic acid). The results indicate that biodegradation of PCB congeners may result in the accumulation of environmentally stable chlorinated biotransformation products in aquatic environments.

Abstract: Cellulose is the major carbon substrate entering treatment plants for municipal waste waters. In the present investigation an attempt was made to study its degradation in activated sludge. Cellulolytic micro-organisms were enumerated in different treatment plants and at one plant they were assessed after different steps over a period of about 1 year. The degradation of cellulose contained in Nylon bags suspended in the mixed liquor was also studied and the activities of cellulase components were assayed. Finally, the concentrations of cellulose and lignin in the suspended solids taken from different treatment steps were determined. The results showed that active cellulolysis occurred in activated sludge. The degradation was mainly bacterial, although no significant enrichment of such bacteria was found in the sludge floc. Cellulase activity, however, showed an increase. Experiments with the Nylon bag indicated that 60% of the weight of cotton wool was degraded in 4–5 weeks. It was concluded that about 60% (w/w) of the cellulose entering the system could be degraded by bacteria during aerobic treatment, while 50–60% of that present in the surplus activated sludge was degraded during anaerobic sludge digestion.

Abstract: The bench scale test demonstrates that substrate availability in the growth medium can significantly effect the biodegradation pattern of commercially formulated PCBs. Under limited substrate supply, all seven major components of Aroclor 1221 were degraded by P. sp. 7509. With excessive amounts of nutrient, however, some preferences for given components were observed. The position of chlorine substitution on the biphenyl molecule appears to be one of the major factors determining an isomer's biodegradability. The biodegradation rate of higher chlorinated PCB formulations was much slower under the continuous loading. However, significant degradation of such formulations did occur, when the fermentor was switched to batch operation.

Abstract: The biodegradability of sodium alkylpoly(oxyalkylene)sulfates was studied under aerobic conditions by oxygen consumption, total organic corbon (TOC) and methylene blue active substance (MBAS) measurements. MBAS of linear alkylpoly(oxyalkylene)sulfates with propylene oxide (APS) or ethylene oxide (AES) disappeared within 5 days, whereas AES with branched alkyl chains were degraded less than linear AES. APS with propylene oxide from 1 to 3 mol showed BOD/ThOD values of more than 40% after 6 days. Therefore, these surfactants are considered to be readily biodegradable. In comparison to the biodegradability of APS and AES, the existence of propylene oxide groups resulted in a slight decreasing in oxygen consumption and TOC removal. Linear APS with PO of 1~3 mol were degraded according to Swisher's distance principle up to a C16 alkyl chain length. That is, increasing distance principle up to a C16 alkyl chain length. That is, increasing distance between sulfate and chain end increased the rate of biodegradation of these surfactants. Furthermore, from the biodegradation test of35S-C12E3S, it is suggested that the initial step of biodegradation is attack on the terminal methyl group.

Abstract: Biodegradation of [14C]tri-p-cresyl phosphate was studied in a laboratory model sewage treatment system to develop information on the nature of its transformation products. In 24-h experiments, 70 to 80% of tri-p-cresyl phosphate added at the 1-μg/ml level was degraded. The remaining parent compound was associated with the sludge solids. The major metabolite extracted with ethyl ether from the aqueous phase was identified as p-hydroxybenzoic acid by gas chromatography-mass spectrometry. Two unstable ether-extractable metabolites were not identified. The half-life of [14C]tri-p-cresyl phosphate was estimated to be 7.5 h.

Abstract: : Amino surfactants at alkaline pHs precipitate 2,4,6-trinitrotoluene (TNT) as a water insoluble complex. Mutagenicity studies indicated these complexes were more potent mutagens than TNT. Soil leaching studies demonstrated that in situ immobilization of TNT in contaminated soils would not be advisable due to the large quantities of surfactant required, the leaching of excess surfactant and sodium hydroxide organic matter extracts into the groundwater, and the inability of the surfactant treatment to immobilize TNT microbial reduction products. Biodegradation studies in soil and water showed there are potential problems with the long term stability of these complexes. Water soluble materials were produced nonbiologically. These compounds were not TNT or any of seven TNT reduction products. Upon concentration, mutagenic activity was found with the filtrate after treatment and filtration of Composition B waste water with Duoquad T-50 at pH 11 in a pilot scale facility.

Abstract: Surfactant biodegradation research is surveyed briefly from its beginnings in the early 1950s when incidents of environmental foaming began to draw attention. Topics include development of test methods, correlations between surfactant structure and biodegradability, biodegradation metabolic pathways, development of commercially feasible biodegradable surfactants and the current environmental situation.

Abstract: The biodegradation of linear alkylbenzene sulfonate (LAS), α-olefine sulfonate (AOS), and alcohol sulfate (AS) were examined under the low dissolved oxygen (DO) condition. Also the accumulation of LAS in sediments was determined.It was showed that these surfactants were biodegraded enough under the condition of less 1 mg/l of DO concentration. Especially AOS and AS were biodegraded very easily. LAS is able to adsorb on sediments in rivers and lakes, but not accumulate so long time because of its biodegradability under the low DO condition.

Abstract: In the present study, the biodegradation of two models has been evaluated under controlled laboratory conditions. A methodology was developed for testing these substances because of their very low solubilities in water. (JMT)

Abstract: Microorganisms of lake sediment and sewage sludge anaerobically metabolized halobenzoates by a novel pathway. The primary degradative event was loss of the aryl halide without the alteration of the aromatic ring. Dehalogenation required strict anaerobic conditions and depended on the halogen and position, but not the number of halogen substituents. A stable methanogenic bacterial consortium was enriched from sludge and found capable of dehalogenating and often mineralizing a variety of halobenzoates to CH4 and CO2. The results suggest that reductive dehalogenation of aromatics could be important in removal of some chlorinated xenobiotics from the environment.