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Increasing textile industries in the last few decade has resulted in the discharge of very large quantities of complex chemical dye to the water system. This has affected the ecological and biological balance causing immense destruction to the nature. In this work, azo dye (Orange G 16) degradation studies by Pseudoalteramonas sp. were investigated. From the experiments, Pseudoalteromonas species degraded the Orange G 16 azo dye at a short time span within 3 h. The assay time for azoreductase activity was standardized, and maximum activity was observed at 24th. The protein concentration was estimated at three different stages of dye degradation. First stage is before addition of dye, second stage is 3 h after addition of the dye during which the dye had completely decolourized, and the third stage is 18 h after the addition of dye. From the study, it was observed that protein concentration was higher in the 24-h sample which has been induced with Orange G 16 azo dye having a concentration of 0.92 mg/ml. While comparing the total activity and specific activity of the enzyme for three samples, it was observed that the activity was higher at the 24th s and then subsided gradually. Thus, Pseudoalteromonas sp. is found to be efficient in degrading azo dyes because of its potential to degrade the dyes rapidly which also has a higher azoreductase activity. [ABSTRACT FROM AUTHOR]

Recently, we showed that Sphingobium fuliginis OMI utilizes 4-tert-butylphenol as a sole carbon and energy source via phenolic ring hydroxylation followed by a meta-cleavage pathway, and that this strain can degrade various alkylphenols. Here, we showed that strain OMI effectively degrades bisphenol A (BPA) via the pathway in which one or two of the phenolic rings of SPA is initially hydroxylated without any modification of the alkyl group that binds the two phenolic rings, and then the aromatic ring is cleaved via a meta- cleavage pathway. Strain OMI also degraded other bisphenols, including bis(4-hydroxyphenyl)methane, bis(4- hydroxyphenyl)sulfone (BPS), 2,2-bis(4-hydroxyphenyl)- butane, bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 4,4'-thiodiphenol (TDP), and 4,4'-dihydroxybenzophenone via phenolic ring hydroxylation and meta-cleavage pathway. To our knowledge, this is the first report to describe the aerobic biodegradation of BPS and TDP. The bisphenols degradation pathway of strain OMI is completely different from the known degradation pathways of BPA or bisphenols, and unique in that it does not appear to be influenced by the chemical structure that binds the two phenolic rings. This newly found pathway may play a certain part in the environmental fate of bisphenols and biotreatment/bioremediation of various bisphenols. [ABSTRACT FROM AUTHOR]

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1. The chemical composition of plant litter is commonly considered to indicate its quality as a resource for decomposer organisms. Litter quality, defined in this way, has been shown to be a major determinant of litter decomposition rates both within and across terrestrial ecosystems. Notably, the structure of the microbial community that is directly responsible for primary decomposition is rarely considered as an empirical predictor of litter decay rates. 2. Microbial communities are generally assumed to perceive litters of the same chemical composition to be of equivalent resource quality but evidence from field studies suggests that these same communities may adapt to the prevalent litter types at a given site. Here, we tested this assumption by assessing how microbial communities sourced from different forest- and herbaceous-dominated ecosystems perceive the quality of novel, foliar litters derived from a tree ( Rhododendron maximum) and from a grass ( Panicum virgatum) species. Based on chemical composition, we would expect R. maximum litter to be of lower quality than P. virgatum litter. 3. We used an experimental litter–soil system which employs a ‘common garden’ approach and measured rates of CO2 production across 50 days; higher rates of production were assumed to indicate higher quality (i.e. more easily degradable) litter. 4. We found that communities sourced from habitats under differing plant cover perceived litter quality differently. Those communities sourced from herbaceous habitats perceived the grass litter to be of higher quality than the tree litter, whereas communities from forest habitats decomposed both litter types similarly. Within a litter type, differences in both community composition and nutrient availability of the source habitat were related to decomposition rates. 5. Our results suggest that litter quality cannot necessarily be predicted solely from chemical characteristics; instead the perceived quality is dependent on the quality of past resource inputs a community has experienced and the structure of those microbial communities responsible for the initial stages of litter decomposition. [ABSTRACT FROM AUTHOR]

Bacterial strains were isolated from endosulfan treated soil to study the microbial degradation of this pesticide in broth medium and soil microcosm. The isolates were grown in minimal medium and screened for endosulfan degradation. The strain, which utilized endosulfan and showed maximum growth, was selected for detail studies. Maximum degrading capability in shake flask culture was shown by Bordetella sp. B9 which degraded 80% of a endosulfan and 86% of β endosulfan in 18 days. Soil microcosm study was also carried out using this strain in six different treatments. Endosulfan ether and endosulfan lactone were the main metabolites in broth culture, while in soil microcosm endosulfan sulfate was also found along with endosulfan ether and endosulfan lactone. This bacterial strain has a potential to be used for bioremediation of the contaminated sites. [ABSTRACT FROM AUTHOR]

Stable isotope fractionation analysis (SIFA) of contaminants is an emerging technique to characterize in situ microbial activity. The kinetic isotope effect in microbial degradation reactions, or enzyme catalysis, is caused by the preferential cleavage of bonds containing light rather than heavy isotopes. This leads to a relative enrichment of the heavier isotopes in the residual substrate pool. However, a number of nonisotopically sensitive steps preceding the isotopically sensitive bond cleavage may affect the reaction kinetics of a degradation process, thus reducing the observed (i.e., the macroscopically detectable) isotope fractionation. Low bioavailability of contaminants poses kinetic limitations on the biodegradation process and can significantly reduce the observed kinetic isotope fractionation. Here we present experimental evidence for the influence of bioavailability-limited pollutant biodegradation on observed stable isotope fractionation. Batch laboratory experiments were performed to quantify the toluene hydrogen isotope fractionation of Pseudomonas putida mt-2(pWWO) subjected to different small concentrations of toluene with and without deuterium label, which corresponded to realistic environmental mass transfer scenarios. Detected isotope fractionations depended significantly on the toluene concentration, hence confirming the influence of substrate mass transfer limitation on observed isotope fractionation, hypothesized by Thullner et al. (Environ. Sci. Technol. 2008, 42, 6544-6551). Our results indicate that the bioavailability of a substrate should be considered during quantitative analysis of microbial degradation based on SIFA. [ABSTRACT FROM AUTHOR]

Five stations were established in the Fenglin mangrove area of Xiamen, China to determine the concentrations of polycyclic aromatic hydrocarbons (PAHs) and the numbers of PAH-degrading bacteria in surface sediments. Assessing the biodegradation potential of indigenous microorganisms and isolating the high molecule weight (HMW)–PAH degrading bacteria was also one of the aims of this work. The results showed that the total PAH concentration of sediments was 222.59ngg−1 dry weight, whereas the HMW–PAH benzo(a)pyrene (BaP) had the highest concentration among 16 individual PAH compounds. The variation in the numbers of PAH-degrading bacteria was 2.62×102–5.67×104 CFUg−1 dry weight. The addition of PAHs showed a great influence in increasing the microbial activity in mangrove sediments. A bacterial consortium, which could utilize BaP as the sole source of carbon and energy, and which was isolated from mangrove sediments and enriched in liquid medium for nearly one year degraded 32.8% of BaP after 63 days incubation. [Copyright &y& Elsevier]

Abstract: Batch experiments were conducted to characterize the degradation of benzo[a]pyrene, a representative high molecular weight (HMW) polycyclic aromatic hydrocarbon (PAH), by Sphingomonas yanoikuyae JAR02. Concentrations up to the solubility limit (1.2μg l−1) of benzo[a]pyrene were completely removed from solution within 20h when the bacterium was grown on salicylate. Additional experiments with [14C]7-benzo[a]pyrene demonstrated 3.8% mineralization over 7days when salicylate was present is solution, and one major radio-labeled metabolite was observed that accounted for ∼10% of the initial radio-label. Further characterization of the radio-labeled metabolite using HPLC/MS and HPLC/MS/MS identified radio-labeled pyrene-8-hydroxy-7-carboxylic acid and unlabeled pyrene-7-hydroxy-8-carboxylic acid as novel ring-cleavage metabolites, and a benzo[a]pyrene degradation pathway was proposed. Results indicate that biostimulation of HMW PAH degradation by salicylate, a water-soluble, non-toxic substrate, has significant potential for in situ bioremediation. [Copyright &y& Elsevier]

For thousands of years wooden foundation piles have been widely used along coastal areas and river sites to stabilise urban settlements. Recent investigations, however, indicate that colonising bacteria can destroy the wood even below the groundwater level under low-oxygen conditions and cause severe strength loss over unexpectedly short periods. Existing knowledge of the species involved and the conditions required for growth of the bacteria is insufficient. The aim of this study was to characterise physicochemical site conditions by taking oxygen, redox potential, and chemical measurements at wooden foundation sites in Amsterdam, The Netherlands, that showed different decay intensities but had comparable sediment profiles. Oxygen (optode principle), redox potential (platinum electrodes), and groundwater table measurements were conducted biweekly over a year. Sediment solution was sampled every three months and analysed for pH, conductivity, total and dissolved carbon and nitrogen, NH4 +, NO3 −, SO4 2−, PO4 3−, Cl−, and major cations. Oxygen and redox measurements indicated oxygen-free conditions at both sites examined, but the water surrounding piles exhibited significantly higher total nitrogen concentrations at the site showing light decay. As other simultaneous investigations revealed a positive correlation between the nitrogen content in wooden pile samples and the decay intensities, we conclude that nitrogen might be a key factor in the decay process. We hypothesise that concentration gradients between sediment and wood matrix may control the decay intensity. [Copyright &y& Elsevier]

We investigated the relationship between wood degradation caused by erosion bacteria and the physicochemical properties of foundations with wooden piles from sites in the Netherlands, Germany, and Italy. Wooden foundation piles have been widely used to stabilise urban settlements along coastal areas and river sites for several millennia. Recently a number of these buildings have suffered from structural instability because their foundations have suddenly lost supporting strength. This loss of strength has been associated with the activity of erosion bacteria that can colonise and destroy wood under low-oxygen conditions, such as those that exist below the groundwater level. Knowledge of bacterial species involved in this process and their growth requirements is sparse, but it has been documented that the damage to wooden foundation piles caused by these bacteria can occur relatively rapidly. Redox potential (platinum electrodes) measurements, sediment, and sedimental water samples were obtained from nine European sites. Sediments were characterised and analysed for total contents of carbon, nitrogen, sulphur, phosphate, and major cations, whereas sedimental water was analysed for pH, conductivity, total and dissolved carbon and nitrogen, , , , , , and major cations. The chemical sediment composition was governed mainly by sediment type (sand, clay), whereas sediment water composition reflected the exposure to sea or freshwater and the redox status of the sampling location. Bacterial wood decay was detected at all sites but with different magnitude orders reflecting the different environments. When the physicochemical properties of sedimental water from foundations in sandy sediments were compared with wood degradation levels, it was observed that decreasing total nitrogen concentration, but not that of phosphate, accompanied increasing bacterial wood decay. [Copyright &y& Elsevier]

The identity of bacteria in waterlogged archaeological wood responsible for degradation was investigated using novel isolation techniques and molecular DNA technology. Wood in cultural heritage and archaeological sites is vulnerable to bacterial attack, with bacterially driven wood-decay predominating when wood is buried in sediments. In the research presented, DNA was extracted directly from wood samples and the diversity of bacterial species was determined. Using cultures isolated by project partners from archaeological wood of the same origin at 19 different European sites, a comparison of the DNA of nine culturable isolates and DNA from species commonly appearing in 56 independent molecular fingerprints was made. Results show that sequences representing bacteria from the Cytophaga-Flavobacterium-Bacteroides (CFB) complex and the Pseudomonas group were commonly recovered, with relatives of the Cellvibrio and Brevundimonas groups also present. These observations are the first to provide a molecular link between environmental samples where degradation had occurred and cultured organisms, although the precise role and capability of the bacterial strains remains obscure. [Copyright &y& Elsevier]

In situ bioremediation is a safe and cost-effective technology for the cleanup of organic-contaminated soil, but its remediation rate is usually very slow, which results primarily from limited mass transfer of pollutants to the degrading bacteria in soil media. This study investigated the feasibility of adopting 2D non-uniform electric field to enhance in situ bioremediation process by promoting the mass transfer of organics to degrading bacteria under in situ conditions. For this purpose, a 2D non-uniform electrokinetic system was designed and tested at bench-scale with a sandy loam as the model soil and 2,4-dichlorophenol (2,4-DCP) as the model organic pollutant at two common operation modes (bidirectional and rotational). Periodically, the electric field reverses its direction at bidirectional mode and revolves a given angle at rotational mode. The results demonstrated that the non-uniform electric field could effectively stimulate the desorption and the movement of 2,4-DCP in the soil. The 2,4-DCP was mobilized through soil media towards the anode at a rate of about 1.0cmd−1 V−1. The results also showed that in situ biodegradation of 2,4-DCP in the soil was greatly enhanced by the applied 2D electric field upon operational mode. At the bidirectional mode, an average 2,4-DCP removal of 73.4% was achieved in 15 days, and the in situ biodegradation of 2,4-DCP was increased by about three times as compared with that uncoupled with electric field, whereas, 34.8% of 2,4-DCP was removed on average in the same time period at the rotational mode. In terms of maintaining remediation uniformity in soil, the rotational operation remarkably excelled the bidirectional operation. In the hexagonal treatment area, the 2,4-DCP removal efficiency adversely increase with the distance to the central electrode at the bidirectional mode, while the rotational mode generated almost uniform removal in soil bed. [Copyright &y& Elsevier]

Seven strains that can degrade nitrobenzene at low temperature were isolated from the sediments of a nitrobenzene-polluted river. One of the strains, NB-1, can mineralize 20 mg/L nitrobenzene completely from 2.5 to 35°C with an optimum temperature of 25°C. NB-1 was identified as Pseudomonas putida according to its morphology, biochemical properties, and 16S rDNA sequence analysis. The strain could tolerate and degrade 120 mg/L nitrobenzene within 175 h at 5°C. It can be used for the bioremediation of nitrobenzene-contaminated environment. [ABSTRACT FROM AUTHOR]

The main objective of this work was to study catabolic potential of marine sediment bacteria in aerobic degradation of polychlorinated biphenyls (PCBs). Marine sediment samples were collected at urban areas of the Croatian Adriatic coast, and microcosm enrichment experiments were performed in seawater mineral salts (SMS) medium with the addition of biphenyl as the only carbon source. After two to four subcultures, all enriched mixed cultures demonstrated the capability to use biphenyl, indicating that biphenyl-utilizing bacteria are widespread in coastal marine sediments. PCB-degrading activity of the enrichment cultures as well as that of their biphenyl-utilizing members were further studied in SMS medium with the addition of PCB mixtures containing di-to heptachlorinated congeners. GC–MS analyses of the extracted cultures suggested that, although they differed in PCB-degrading capabilities, all of the enrichment cultures expressed activity toward at least some of the lower chlorinated congeners (di-to tetrachlorobiphenyls). Biphenyl-utilizing bacteria isolated from the most active PCB-degrading mixed cultures showed little taxonomic diversity (six out of seven isolates belonged to the genus Rhodococcus and one to the genus Sphingomonas). All isolated Rhodococcus strains (R. erythropolis and R. ruber) showed substantial PCB-degrading activity, suggesting that these bacteria might play an important role in aerobic PCB degradation in polluted marine sediment. [Copyright &y& Elsevier]

In order to gain insight into the community structure and the biodegradative potential of bacteria residing in a BTEX-contaminated field site, with benzene as main pollutant, an investigation strategy with a variety of cultivation-independent and -dependent approaches was undertaken. Based on 16S ribosomal DNA sequence analysis, sampling stations in the center of the pollution plume were found to be dominated by a bacterial consortium affiliated with various members of the class of Proteobacteria and Firmicutes, including different sporulating and non-sporulating sulfate-reducing bacteria and members of the genus Geobacter. Non-polluted samples retrieved from outside the plume revealed several phylotypes which were also observed in the centre of the plume. Bacterial sequences retrieved from the fringe of the plume were dominated by several genera of beta Proteobacteria subclass which were not associated with other phylotypes obtained in this study. All sampling stations were tested positive for catechol 2,3-dioxygenase genes, indicating the presence of microorganisms with the genetic potential degrading aromatic compounds via the meta-cleavage pathway. The groundwater system at the down-gradient edge of the plume was characterized, in contrast to all other sampling stations in the center and outside the plume, by high numbers of cultivable bacteria and cultivable aerobic benzene and toluene degraders. These findings are also in accordance with the investigations based on fluorescent in situ hybridization (FISH) with rRNA-targeted oligonucleotide probes, suggesting the presence of an actively benzene degrading bacterial community of beta Proteobacteria at the fringe of the pollution plume. [ABSTRACT FROM AUTHOR]

A study was conducted to determine the efficiency and effectiveness of two commercial microbial based bioremediation products compared to indigenous tropical microorganisms in a small-scale trial. The oil and grease content of the samples was monitored as an indication of the levels of petroleum hydrocarbon during the experiment. The indigenous enriched culture generally biodegraded the petroleum hydrocarbon to a greater extent than the commercial products and media controls early in the bioremediation process (0–5 days). However, as time progressed the extents of biodegradation were not significantly different between treatments until late in the bioremediation process (after 18 days). Of the two commercial products, one was more effective, reducing the level of oil and grease by 52.5% over the 3 week study. However, neither commercial product was able to meet the manufacturer’s stated level of 95% removal within three weeks. Commercial microbial-based bioremediation products may be used with some success in tropical environments, however location-specific trials may be required to ensure that the best commercial product is selected. As an alternative, the selective enrichment of indigenous microorganisms may result in similar performance at a reduced cost. [ABSTRACT FROM AUTHOR]

A novel bacterium designated strain B-16 was isolated from the compost leachate of the municipal solid waste (MSW) in a laboratory reactor. This strain was identified as a gram-negative bacterium, Achromobacter xylosoxidans that could grow on bisphenol A (BPA, a representative endocrine disruptor) as a sole carbon source under aerobic condition. BPA-degrading characteristics of strain B-16 were investigated in liquid cultures. The results show that BPA degradation was influenced by several factors (e.g. inoculum size, substrate concentration, temperature and pH, etc). The half-lives, optimum temperature and pH were found to be 0. 58–3. 1d, 35°C and 7. 0, respectively. BPA-degrading activity and cell growth were inhibited at high substrate concentration. Metabolic intermediates detected during the degradation process were identified as p-hydroxybenzaldehyde, p-hydroxybenzoic acid and p-hydroquinone, respectively. Metabolic pathway of BPA degradation was proposed in this study. [Copyright &y& Elsevier]

Burkholderia sp. C3 was isolated from a polycyclic aromatic hydrocarbon (PAH)-contaminated site in Hilo, Hawaii, USA, and studied for its degradation of phenanthrene as a sole carbon source. The initial 3,4-C dioxygenation was faster than 1,2-C dioxygenation in the first 3-day culture. However, 1-hydroxy-2-naphthoic acid derived from 3,4-C dioxygenation degraded much slower than 2-hydroxy-1-naphthoic acid derived from 1,2-C dioxygenation. Slow degradation of 1-hydroxy-2-naphthoic acid relative to 2-hydroxy-1-naphthoic acid may trigger 1,2-C dioxygenation faster after 3 days of culture. High concentrations of 5,6-and 7,8-benzocoumarins indicated that meta-cleavage was the major degradation mechanism of phenanthrene-1,2-and-3,4-diols. Separate cultures with 2-hydroxy-1-naphthoic acid and 1-hydroxy-2-naphthoic acid showed that the degradation rate of the former to naphthalene-1,2-diol was much faster than that of the latter. The two upper metabolic pathways of phenanthrene are converged into naphthalene-1,2-diol that is further metabolized to 2-carboxycinnamic acid and 2-hydroxybenzalpyruvic acid by ortho-and meta-cleavages, respectively. Transformation of naphthalene-1,2-diol to 2-carboxycinnamic acid by this strain represents the first observation of ortho-cleavage of two rings-PAH-diols by a Gram-negative species. [ABSTRACT FROM AUTHOR]

Contamination of groundwater with the gasoline additive methyl tert-butyl ether (MTBE) is often accompanied by many aromatic components such as benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene (BTEX). In this study, a laboratory-scale biotrickling filter for groundwater treatment inoculated with a microbial consortium degrading MTBE was studied. Individual or mixtures of BTEX compounds were transiently loaded in combination with MTBE. The results indicated that single BTEX compound or BTEX mixtures inhibited MTBE degradation to varying degrees, but none of them completely repressed the metabolic degradation in the biotrickling filter. Tert-butyl alcohol (TBA), a frequent co-contaminant of MTBE had no inhibitory effect on MTBE degradation. The bacterial consortium was stable and showed promising capabilities to remove TBA, ethylbenzene and toluene, and partially degraded benzene and xylenes without significant lag time. The study suggests that it is feasible to deploy a mixed bacterial consortia to degrade MTBE, BTEX and TBA at the same time. [ABSTRACT FROM AUTHOR]

Fenitrothion, a toxic organophosphorus pesticide, can build up the concentration of nitrophenolic compound in soils and hence needs to be removed. Burkholderia sp. FDS-1, a fenitrothion-degrading strain, was used in this work to study factors affecting its growth, and then evaluated for its capacity to degrade fenitrothion in soil microcosms. Minimal salt medium containing 1% (w/v) glucose was found to be a suitable carbon source for inoculum preparation. Various factors, including soil pH, temperature, initial fenitrothion concentration, and inoculum size influenced the degradation of fenitrothion. Microcosm studies performed with varying concentrations (1–200mgkg−1) of fenitrothion-spiked soils showed that strain FDS-1 could effectively degrade fenitrothion in the range of 1–50mgkg−1 soil. The addition of Burkholderia sp. FDS-1 at 2×106 colony forming unitsg−1 soil was found to be suitable for fenitrothion degradation over a temperature range of 20–40°C and at a slight alkaline pH (7. 5). The results indicate that strain FDS-1 has potential for use in bioremediation of fenitrothion and its metabolite-contaminated sites. This is a model study that could be used for decontamination of sites contaminated with other compounds. [Copyright &y& Elsevier]

Two strains of bacteria were isolated from deep-ocean sediments of the South China Sea using enrichment culturing technique and they were identified as Sphingomonas yanoikuyae DOS01 (AY878409) and Variovorax paradoxus T4 (AY878410) based on 16S rRNA gene sequences. S. yanoikuyae DOS01 was only capable of transforming dimethyl terephthalate (DMTP) to monomethyl terephthalate (MMTP) without further degradation while V. paradoxus T4 exhibited ability in mineralizing DMTP as the sole source of carbon and energy. The biochemical pathway of DMTP degradation was through MMTP and terephthalic acid (TA) as major detectable degradation intermediates in the culture media by both microorganisms. V. paradoxus T4 utilized DMTP and MMTP via hydrolysis of diester and monoester in the initial steps in degradation as confirmed by total organic carbon analysis of the culture medium and esterase activity assay of the lysed cells and fraction. The specific hydrolysis activity of esterase induced by DMTP or MMTP showed that greater hydrolysis of p-nitrophenyl acetate by esterase induced by DMTP-grown cells than that induced by MMTP. Results of this research suggest that the cleavage of the two identical carboxylic ester groups of phthalate diester are carried out by highly specific esterases of the same bacteria in the environment. [ABSTRACT FROM AUTHOR]

Experiments on the biodegradation of unusable medicines containing a phenolic hydroxy group by actinobacteria of the genus Rhodococcus were performed. Six species and sixty-four strains were tested. It was found that rhodococci could degrade paracetamol, and some R. ruber strains showed high levels of its degradation. An efficient method for the identification and quantification of paracetamol and the products of its conversion ( p-aminophenol, pyrocatechol, and hydroquinone) immediately in the culture liquid was developed. Conditions for the complete biodegradation of paracetamol dosage forms (pills) were optimized. The experimental results can be applied to the development of biotechnological methods for degrading medicines: faked, rejected, or those that are expired. [ABSTRACT FROM AUTHOR]

Degradation of dimethyl isophthalate (DMI) and dimethyl phthalate ester (DMPE) was investigated using microorganisms isolated from mangrove sediment of Hong Kong Mai Po Nature Reserve. One enrichment culture was capable of utilizing DMI as the sole source of carbon and energy, but none of the bacteria in the enrichment culture was capable of degrading DMI alone. In co-culture of two bacteria, degradation was observed proceeding through monomethyl isophthalate (MMI) ester and isophthalic acid (IPA) before the aromatic ring opening. Using DMI as the sole carbon and energy source, Klebsiella oxytoca Sc and Methylobacterium mesophilicum Sr degraded DMI through the biochemical cooperation. The initial hydrolytic reaction of the ester bond was by K. oxytoca Sc and the next step of transformation was by M. mesophilicum Sr, and IPA was degraded by both of them. In another investigation, a novel bacterium, strain MPsc, was isolated for degradation of dimethyl phthalate ester (DMPE) also from the mangrove sediment. On the basis of phenotypic, biochemical and 16S rDNA gene sequence analyses, the strain MPsc should be considered as a new bacterium at the genus level (8% differences). This strain, together with a Rhodococcus zopfii isolated from the same mangrove sediment, was able to degrade DMPE aerobically. The consortium consisting of the two species degraded 450 mg/l DMPE within 3 days as the sole source of carbon and energy, but none of the individual species alone was able to transform DMPE. Furthermore, the biochemical degradation pathway proceeded through monomethyl phthalate (MMP), phthalic acid (PA) and then protocatechuate before aromatic ring cleavage. Our results suggest that degradation of complex organic compounds including DMI and DMPE may be carried out by several members of microorganisms working together in the natural environments. [ABSTRACT FROM AUTHOR]