Bacterial metabolism of carbofuran.

Fifteen bacteria capable of degrading carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate) were isolated from soil samples with a history of pesticide application. All isolates were gram negative and were oxidase- and catalase-positive rods; they occurred singly or as short chains. All of the identified isolates belonged to one of two genera, Pseudomonas and Flavobacterium. They were separated into three groups based on their mode of utilization of carbofuran. Six isolates were placed in group I; these isolates utilized carbofuran as a sole source of nitrogen. Seven isolates were placed in group II; these isolates utilized the pesticide as a sole source of carbon. Isolates of both groups I and II hydrolyzed carbofuran to carbofuran phenol. Two isolates, designated group III, also utilized carbofuran as a sole source of carbon. They degraded the pesticide more rapidly, however, so up to 40% of [14C]carbofuran was lost as 14CO2 in 1 h. The results suggest that these isolates degrade carbofuran by utilizing an oxidative pathway.     

Bacterial metabolism of carbofuran

Fifteen bacteria capable of degrading carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate) were isolated from soil samples with a history of pesticide application. All isolates were gram negative and were oxidase- and catalase-positive rods; they occurred singly or as short chains. All of the identified isolates belonged to one of two genera, Pseudomonas and Flavobacterium. They were separated into three groups based on their mode of utilization of carbofuran. Six isolates were placed in group I; these isolates utilized carbofuran as a sole source of nitrogen. Seven isolates were placed in group II; these isolates utilized the pesticide as a sole source of carbon. Isolates of both groups I and II hydrolyzed carbofuran to carbofuran phenol. Two isolates, designated group III, also utilized carbofuran as a sole source of carbon. They degraded the pesticide more rapidly, however, so up to 40% of [14C]carbofuran was lost as 14CO2 in 1 h. The results suggest that these isolates degrade carbofuran by utilizing an oxidative pathway.     

Molecular diversity of tannic acid degrading bacteria isolated from tannery soil

AIMS: The aim of this study was to enrich and isolate bacteria from a tannery soil that were capable of utilizing tannic acid and gallic acid as sole source of carbon aerobically, and to characterize their diversity in order to identify efficient strains that can be used for tannin bioremediation. METHODS AND RESULTS: Bacterial strains were isolated after enrichment in minimal medium with tannic acid or gallic acid as sole carbon source. Polymerase chain reaction (PCR) restricted fragment length polymorphism of 16S rDNA [amplified ribosomal DNA restriction analysis (ARDRA)] and BOX-PCR was used to characterize their diversity. Two strains showing relatively high efficiency in degrading tannic acid and gallic acid were identified on the basis of carbon source utilization pattern (BIOLOG) and 16S rDNA sequence. CONCLUSIONS: Bacterial strains capable of degrading tannic acid and gallic acid could be grouped into six and seven clusters on the basis of ARDRA and BOX-PCR, respectively. On the basis of 16S rDNA sequence, the most efficient isolate degrading tannic acid belonged to Pseudomonas citronellolis, whereas the most efficient gallic acid degrader showed maximum phylogenetic relatedness to P. plecoglossicida. SIGNIFICANCE AND IMPACT OF THE STUDY: Aerobic tannic acid degraders such as the two strains isolated in this study can be used for tannin bioremediation, and in the study of genes involved in the production of tannase, an industrially important enzyme.     

Utilization of Iron Gallate and Other Organic Iron Complexes by Bacteria from Water Supplies

The degradation of four soluble organic iron compounds by bacteria isolated from surface waters and the precipitation of iron from these complexes by the isolates was studied. All eight isolates brought about the precipitation of iron when grown on ferric ammonium citrate agar. Three isolates were able to degrade ferric malonate, and three others degraded ferric malate with iron precipitation. Only three isolates, two strains of Pseudomonas and one of Moraxella, were able to degrade gallic acid when this was supplied as the sole carbon source. One strain of Pseudomonas was found to be active in degrading ferric gallate. Electron microscopy of cells of this bacterium after growth in ferric gallate as the sole carbon source yielded results indicating uniform deposition of the iron on or in the bacterial cells. Seven of the isolates could degrade the iron gallate complex if supplied with additional carbon in the form of yeast extract.     

长链烷烃降解菌的降解特性

对长链烷烃降解菌的降解能力和摄取模式进行了研究。评价14株烃降解菌利用中长链烃生长的能力,发现只有少数烃降解菌能够获得良好生长,其中Mycobacterium fortuitum514,Pseudomonas aeruginosa1785和Pseudomonas marginata766等3株菌能够高效降解C20到C33的长链烷烃。辛烷不能支持这些长链烷烃降解菌的生长,说明其烃氧化酶与Pseudomonas oleovorans的OCT质粒编码的单氧酶不同。此外,M.fortuitum不产胞外表面活性剂,而P.aeruginosa和P.marginata则是表面活性剂产生菌,然而三者在以烃为碳源生长时均显示出很高的细胞表面疏水性。根据生长现象分析3株菌采用了不同的烷烃摄取模式。     

Cloning and Expression of OX-DAPRO Degrading Genes from Soil Microbe

The strain BYK 1, capable ot utilizing DAP or OX-DAPRO as a sole source ot nitrogen and carbon was Identitied as Pseudomonas stutzeri by various microbial and biochemical tests. Transtormation experiments showed that the OX-DAPRO utilization property Is encoded by the plasmid. Restriction of the plasmid DNA toll owed by cloning ot fragments and screening on OX-DAPRO medium led to Isolation of a clone with DNA Insert of ～ 2.2 kb (designated as BSKS) which encoded OX-DAPRO degrading gel)e. The growth and OX-DAPRO utilization with this fragment was similar to wild type strain.     

Mesophilic aerobic Gram negative cellulose degrading bacteria from aquatic habitats and soils

New procedures have been developed for the isolation and purification of aerobic and facultatively anaerobic bacteria able to utilize cellulose as sole source of carbon and energy. Wood pulp medium was used for enrichment, and bacterial cellulose, obtained from cultures of Acetobacter aceti subsp. xylinus , was employed as carbon substrate during purification and for the rapid screening of colonies for cellulolytic activity. The methods have revealed several new groups of Gram negative cellulose-degrading bacteria, including organisms that form differentiated colonies superficially similar to myxobacterial sori. The organisms formed several phenetic clusters, three of which contained reference strains of Cellvibrio fulvus, Pseudomonas fluorescens var. cellulosa and Cytophaga hutchinsonii . No cellulose degrading cluster included non-cellulose degrading strains. Most of the cellulose degraders studied were flagellated and, of these, the majority had polar or lophotrichous flagella, although one cluster included peritrichously flagellated organisms. The cellulose degraders in this study included five organisms that grew on nitrate-free medium; these appeared in two different clusters. A few Gram positive isolates appeared to belong to the genera Streptomyces and Thermoactinomyces .     

Bacterial metabolism of 3-chloroacrylic acid.

Two bacterial strains were isolated with 3-chloroacrylic acid (CAA) as sole source of carbon and energy. Strain CAA1, a Pseudomonas cepacia sp., was capable of growth with only the cis-isomer of CAA. Strain CAA2, a coryneform bacterium, utilized both isomers of CAA as sole source of carbon and energy. Strain CAA1 contained cis-CAA hydratase and strain CAA2 contained two hydratases, one with cis-CAA hydratase activity and one with trans-CAA hydratase activity. The product of the hydratase activities with CAA was malonate semialdehyde. In both strains malonate semialdehyde was subsequently decarboxylated by a cofactor-independent decarboxylase yielding acetaldehyde and CO2.     

Simultaneous degradation of acetonitrile and biphenyl by Pseudomonas aeruginosa

A bacterium capable of utilizing either acetonitrile as the sole source of carbon and nitrogen or biphenyl as the sole source of carbon was isolated from soil and identified as Pseudomonas aeruginosa. The bacterium also utilized other nitriles, amides, and polychlorinated biphenyls (PCBs) as growth substrates. Acetonitrile- or biphenyl-grown cells oxidized these substrates without a lag. In studies with [14C]acetonitrile, nearly 74% of the carbon was recovered as 14CO2 and 8% was associated with the biomass. In studies with [14C]biphenyl, nearly 68% of the carbon was recovered as 14CO2 and nearly 6% was associated with the biomass. Although higher concentrations of acetonitrile as the sole sources of nitrogen inhibited the rates of [14C]biphenyl mineralization, lower concentrations (0.05%, w/v) gave a 77% stimulation in 14CO2 recovery. Pseudomonas aeruginosa metabolized acetonitrile to ammonia and acetic acid and biphenyl to benzoic acid. The bacterium also simultaneously utilized biphenyl as the sole carbon source and acetonitrile as the sole nitrogen source. However, biphenyl utilization increased only after the depletion of acetonitrile. Metabolites of the mixed substrate were ammonia and benzoic acid, which completely disappeared in the later stages of incubation. Nitrile hydratase and amidase were responsible for the transformation of acetonitrile to acetic acid and ammonia.     

Biodegradation of Nitriles in Shale Oil

Enrichment cultures were obtained, after prolonged incubation on a shale oil as the sole source of nitrogen, that selectively degraded nitriles. Capillary gas chromatographic analyses showed that the mixed microbial populations in the enrichments degraded the homologous series of aliphatic nitriles but not the aliphatic hydrocarbons, aromatic hydrocarbons, or heterocyclic-nitrogen compounds found in this oil. Time course studies showed that lighter nitriles were removed more rapidly than higher-molecular-weight nitriles. A Pseudomonas fluorescens strain isolated from an enrichment, which was able to completely utilize the individual nitriles undecyl cyanide and undecanenitrile as sole sources of carbon and nitrogen, was unable to attack stearonitrile when provided alone as the growth substrate. A P. aeruginosa strain, also isolated from one of the enrichments, used nitriles but not aliphatic or aromatic hydrocarbons when the oil was used as a sole nitrogen source. However, when the shale oil was used as the sole source of carbon, aliphatic hydrocarbons in addition to nitriles were degraded but aromatic hydrocarbons were still not attacked by this P. aeruginosa strain.     

Degradation of fluoranthene, pyrene, benz[a]anthracene and dibenz[a,h]anthracene by Burkholderia cepacia

Microbiological analysis of soils from a polycyclic aromatic hydrocarbon (PAH)-contaminated site resulted in the enrichment of five microbial communities capable of utilizing pyrene as a sole carbon and energy source. Communities 4 and 5 rapidly degraded a number of different PAH compounds. Three pure cultures were isolated from community 5 using a spray plate method with pyrene as the sole carbon source. The cultures were identified as strains of Burkholderia ( Pseudomonas ) cepacia on the basis of biochemical and growth tests. The pure cultures (VUN 10 001, VUN 10 002 and VUN 10 003) were capable of degrading fluorene, phenanthrene and pyrene (100 mg l⁻¹) to undetectable levels within 7–10 d in standard serum bottle cultures. Pyrene degradation was observed at concentrations up to 1000 mg l⁻¹. The three isolates were also able to degrade other PAHs including fluoranthene, benz[ a ]anthracene and dibenz[ a , h ]anthracene as sole carbon and energy sources. Stimulation of dibenz[ a , h ]anthracene and benzo[ a ]pyrene degradation was achieved by the addition of small quantities of phenanthrene to cultures containing these compounds. Substrate utilization tests revealed that these micro-organisms could also grow on n -alkanes, chlorinated- and nitro-aromatic compounds.     

Isolation and characterization of novel atrazine-degrading microorganisms from an agricultural soil

Six previously undescribed microorganisms capable of atrazine degradation were isolated from an agricultural soil that received repeated exposures of the commonly used herbicides atrazine and acetochlor. These isolates are all Gram-positive and group with microorganisms in the genera Nocardioides and Arthrobacter, both of which contain previously described atrazine degraders. All six isolates were capable of utilizing atrazine as a sole nitrogen source when provided with glucose as a separate carbon source. Under the culture conditions used, none of the isolates could utilize atrazine as the sole carbon and nitrogen source. We used several polymerase-chain-reaction-based assays to screen for the presence of a number of atrazine-degrading genes and verified their identity through sequencing. All six isolates contain trzN and atzC, two well-characterized genes involved in the conversion of atrazine to cyanuric acid. An additional atrazine-degrading gene, atzB, was detected in one of the isolates as well, yet none appeared to contain atzA, a commonly encountered gene in atrazine impacted soils and atrazine-degrading isolates. Interestingly, the deoxyribonucleic acid sequences of trzN and atzC were all identical, implying that their presence may be the result of horizontal gene transfer among these isolates.     

Isolation and characterization of a bacterium which utilizes polyester polyurethane as a sole carbon and nitrogen source

Abstract Various soil samples were screened for the presence of microorganisms which have the ability to degrade polyurethane compounds. Two strains with good polyurethane degrading activity were isolated. The more active strain was tentatively identified as Comamonas acidovorans . This strain could utilize polyester-type polyurethanes but not the polyether-type polyurethanes as sole carbon and nitrogen sources. Adipic acid and diethylene glycol were probably the main degradation products when polyurethane was supplied as a sole carbon and nitrogen source. When ammonium nitrate was used as nitrogen source, only diethylene glycol was detected after growth on polyurethane.     

Factors influencing the ability of Pseudomonas putida strains epI and II to degrade the organophosphate ethoprophos

Two strains of Pseudomonas putida (epI and epII), isolated previously from ethoprophos-treated soil, were able to degrade ethoprophos (10 mg 1(-1)) in a mineral salts medium plus nitrogen (MSMN) in less than 50 h with a concurrent population growth. Addition of glucose or succinate to MSMN did not influence the degrading ability of Ps. putida epI, but increased the lag phase before rapid degradation commenced with Ps. putida epII. The degrading ability of the two isolates was lost when the pesticide provided the sole source of phosphorus. Degradation of ethoprophos was most rapid when bacterial cultures were incubated at 25 and 37 degrees C. Pseudomonas putida epI was capable of completely degrading ethoprophos at a slow rate at 5 degrees C, compared with Ps. putida epII which could not completely degrade ethoprophos at the same time. Pseudomonas putida epI was capable of degrading ethoprophos when only 60 cells ml(-1) were used as initial inoculum. In contrast, Ps. putida epII was able to totally degrade ethoprophos when inoculum densities of 600 cells ml(-1) or higher were used. In general, longer lag phases accompanied the lower inoculum levels. Both isolates rapidly degraded ethoprophos in MSMN at pHs ranging from 5.5 to 7.6, but not at pH 5 or below.     

Isolation and characterization of monochloroacetic acid-degrading bacteria

Five Burkholderia strains (CL-1, CL-2, CL-3, CL-4, and CL-5) capable of degrading monochloroacetic acid (MCA) were isolated from activated sludge or soil samples gathered from several parts of Japan. All five isolates were able to grow on MCA as the sole source of carbon and energy, and argentometry and gas chromatography-mass spectroscopy analyses showed that these five strains consumed MCA completely and released chloride ions stoichiometrically within 25 h. The five isolates also grew on monobromoacetic acid, monoiodoacetic acid, and L-2-monochloropropionic acid as sole sources of carbon and energy. In addition, the five isolates could not grow with DCA but dehalogenate single chlorine from DCA. Because PCR analyses revealed that all five isolates have an identical group II dehalogenase gene fragment and no group I deh gene, only strain CL-1 was analyzed further. The partial amino acid sequence of the group II dehalogenase of strain CL-1, named DehCL1, showed 74.6% and 65.2% identities to corresponding regions of the two MCA dehalogenases, DehCI from Pseudomonas sp. strain CBS-3 and Hdl IVa from Burkholderia cepacia strain MBA4, respectively. The secondary-structure motifs of the haloacid dehalogenase (HAD) superfamily and the amino acid residues involved in substrate binding, catalysis, and hydrophobic pocket formation were conserved in the partial amino acid sequence of DehCL1.     

Isolation and Characterization of Novel Strains of <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> and <Emphasis Type="Italic">Serratia marcescens</Emphasis> Possessing High Efficiency to Degrade Gasoline,Kerosene, Diesel Oil,and Lubricating Oil

Bacteria possessing high capacity to degrade gasoline, kerosene, diesel oil, and lubricating oil were screened from several areas of Hokkaido, Japan. Among isolates, two strains, WatG and HokM, which were identified as new strains of Pseudomonas aeruginosa and Serratia marcescens species, respectively, showed relatively high capacity and wide spectrum to degrade the hydrocarbons in gasoline, kerosene, diesel, and lubricating oil. About 90-95% of excess amount of total diesel oil and kerosene added to mineral salts media as a sole carbon source could be degraded by WatG within 2 and 3 weeks, respectively. The same amount of lubricating oil was 60% degraded within 2 weeks. Strain HokM was more capable than WatG in degrading aromatic compounds in gasoline. This strain could also degrade kerosene, diesel, and lubricating oil with a capacity of 50-60%. Thus, these two isolates have potential to be useful for bioremediation of sites highly contaminated with petroleum hydrocarbons.     

Isolation and characterization of atrazine-degrading Arthrobacter sp. strains from Argentine agricultural soils

Three bacterial strains capable of degrading atrazine were isolated from Manfredi soils (Argentine) using enrichment culture techniques. These soils were used to grow corn and were treated with atrazine for weed control during 3 years. The strains were nonmotile Gram-positive bacilli which formed cleared zones on atrazine solid medium, and the 16S rDNA sequences indicated that they were Arthrobacter sp. strains. The atrazine-degrading activity of the isolates was characterized by the ability to grow with atrazine as the sole nitrogen source, the concomitant herbicide disappearance, and the chloride release. The atrazine-degrader strain Pseudomonas sp. ADP was used for comparative purposes. According to the results, all of the isolates used atrazine as sole source of nitrogen, and sucrose and sodium citrate as the carbon sources for growth. HPLC analyses confirmed herbicide clearance. PCR analysis revealed the presence of the atrazine catabolic genes trzN, atzB, and atzC. The results of this work lead to a better understanding of microbial degradation activity in order to consider the potential application of the isolated strains in bioremediation of atrazine-polluted agricultural soils in Argentina.     

Evidence for the presence of a CmuA methyltransferase pathway in novel marine methyl halide-oxidizing bacteria

Marine bacteria that oxidized methyl bromide and methyl chloride were enriched and isolated from seawater samples. Six methyl halide-oxidizing enrichments were established from which 13 isolates that grew on methyl bromide and methyl chloride as sole sources of carbon and energy were isolated and maintained. All isolates belonged to three different clades in the Roseobacter group of the alpha subdivision of the Proteobacteria and were distinct from Leisingera methylohalidivorans, the only other identified marine bacterium that grows on methyl bromide as sole source of carbon and energy. Genes encoding the methyltransferase/corrinoid-binding protein CmuA, which is responsible for the initial step of methyl chloride oxidation in terrestrial methyl halide-oxidizing bacteria, were detected in enrichments and some of the novel marine strains. Gene clusters containing cmuA and other genes implicated in the metabolism of methyl halides were cloned from two of the isolates. Expression of CmuA during growth on methyl halides was demonstrated by analysis of polypeptides expressed during growth on methyl halides by SDS-PAGE and mass spectrometry in two isolates representing two of the three clades. These findings indicate that certain marine methyl halide degrading bacteria from the Roseobacter group contain a methyltransferase pathway for oxidation of methyl bromide that may be similar to that responsible for methyl chloride oxidation in Methylobacterium chloromethanicum. This pathway therefore potentially contributes to cycling of methyl halides in both terrestrial and marine environments.     

Enrichment and identification of bacteria capable of reducing chemical oxygen demand of anaerobically treated molasses spent wash

AIMS: The aim of this study was to isolate and identify bacterial strains capable of using recalcitrant compounds of molasses spent wash as sole carbon source from the soils of abandoned sites of distillery effluent discharge and characterize their ability of reducing the chemical oxygen demand (COD) of the spent wash. METHODS AND RESULTS: The isolates were grouped into six haplotypes by amplified ribosomal DNA restriction analysis (ARDRA) and BOX-PCR. The phylogenetic position of the representatives of the six main haplotypes strains was determined by 16S rDNA sequencing. They showed maximum similarity to six genera viz. Pseudomonas, Enterobacter, Stenotrophomonas, Aeromonas, Acinetobacter and Klebsiella. The extent of COD (44%) reduced collectively by the six strains was equal to that reduced individually by Aeromonas, Acinetobacter, Pseudomonas and Enterobacter. With spent wash as sole carbon source, the COD reducing strains grew faster at 37 degrees C than 30 degrees C. CONCLUSIONS: Bacterial strains capable of degrading some of the recalcitrant compounds of anaerobically digested molasses spent wash can be isolated from the soils of abandoned sites of distillery effluent discharge. Biostimulation of these bacteria, which can degrade 44% of the carbon compounds of anaerobically digested molasses spent wash can be achieved by nitrogen fertilization and relatively higher temperature. SIGNIFICANCE AND IMPACT OF THE STUDY: Supplementation of nitrogen source and controlling the temperature can be used in evolving strategies for in situ bioremediation of anaerobically digested spent wash from distilleries.     

The microbial degradation of phenylalkanes. 2-Phenylbutane, 3-phenylpentane, 3-phenyldodecane and 4-phenylheptane

1. Two Pseudomonas strains capable of utilizing 2-phenylbutane, 3-phenylpentane and 4-phenylheptane as the sole carbon and energy source were isolated. 2. Two Nocardia strains capable of utilizing only 3-phenyldodecane as the sole carbon and energy source were isolated. 3. All the isolated strains were unable to grow on the corresponding phenylalkane-p-sulphonates. 4. From liquid cultures of Pseudomonas strains utilizing 2-phenylbutane, 2-(2,3-dihydro-2,3-dihydroxyphenyl)butane was isolated and identified. Evidence for a meta cleavage of the benzene ring was also obtained. 5. From liquid cultures of Pseudomonas strains utilizing 3-phenylpentane, 3-(2,3-dihydro-2,3-dihydroxyphenyl)pentane and 2-hydroxy-7-ethyl-6-oxonona-2,4-dienoic acid were isolated and identified. 6. Evidence for the formation of both a diol and a meta-cleavage compound was obtained from liquid cultures of both Pseudomonas strains utilizing 4-phenylheptane. 7. Liquid cultures of both Nocardia strains utilizing 3-phenyldodecane never formed a diol or a semialdehyde-related compound. 2-Phenylbutyric acid, 3-phenylvaleric acid and 4-phenylhexanoic acid were shown to be present in these cultures.