节杆菌PJ3降解咔唑和联苯

菌株PJ3经16SrDNA鉴定为节杆菌(Arthrobacter sp.),同源树表明,该菌株与已报道咔唑降解菌株IC177同源关系最近,其次是联苯降解菌株K37和R04。为了明确PJ3菌株对咔唑和联苯的降解能力,在PJ3生长的最适pH值进行优化的基础上,利用分光光度法测定了该菌株在不同浓度咔唑和联苯的矿物培养基中的生长速率以及对咔唑和联苯的降解性能。结果表明,在pH为7、8、9时,PJ3菌株的生长速率一致,而且高于其他pH值的生长速率。在pH为7、咔唑浓度为0.1mg.ml-1的CNFMM培养基中,PJ3菌株生长速度较快,而且15d咔唑的降解率可达到73%。在pH为7、联苯浓度为0.5mg.ml-1的MSB培养基中PJ3菌株生长最好。在0.1和0.5mg.ml-1联苯浓度下,15d对联苯的降解率可达80%～85%。综合评价,PJ3菌株降解咔唑比较适宜的浓度范围应该为0.1～0.2mg.ml-1,降解联苯较适宜的浓度范围为0.1～0.5mg.ml-1。     

Biodegradation of 3-nitrotoluene by Rhodococcus sp. strain ZWL3NT

A pure bacterial culture was isolated by its ability to utilize 3-nitrotoluene (3NT) as the sole source of carbon, nitrogen, and energy for growth. Analysis of its 16S rRNA gene showed that the organism (strain ZWL3NT) belongs to the genus Rhodococcus. A rapid disappearance of 3NT with concomitant release of nitrite was observed when strain ZWL3NT was grown on 3NT. The isolate also grew on 2-nitrotoluene, 3-methylcatechol and catechol. Two metabolites, 3-methylcatechol and 2-methyl-cis,cis-muconate, in the reaction mixture were detected after incubation of cells of strain ZWL3NT with 3NT. Enzyme assays showed the presence of both catechol 1,2-dioxygenase and catechol 2,3-dioxygenase in strain ZWL3NT. In addition, a catechol degradation gene cluster (catRABC cluster) for catechol ortho-cleavage pathway was cloned from this strain and cell extracts of Escherichia coli expressing CatA and CatB exhibited catechol 1,2-dioxygenase activity and cis,cis-muconate cycloisomerase activity, respectively. These experimental evidences suggest a novel pathway for 3NT degradation with 3-methylcatechol as a key metabolite by Rhodococcus sp. strain ZWL3NT.     

Biodegradation of 2-nitrotoluene by Pseudomonas sp. strain JS42.

A strain of Pseudomonas sp. was isolated from nitrobenzene-contaminated soil and groundwater on 2-nitrotoluene as the sole source of carbon, energy, and nitrogen. Bacterial cells growing on 2-nitrotoluene released nitrite into the growth medium. The isolate also grew on 3-methylcatechol, 4-methylcatechol, and catechol. 2-Nitrotoluene, 3-methylcatechol, and catechol stimulated oxygen consumption by intact cells regardless of the growth substrate. Crude extracts from the isolate contained catechol 2,3-dioxygenase and 2-hydroxy-6-oxohepta-2,4-dienoate hydrolase activity. The results suggest that 2-nitrotoluene is subject to initial attack by a dioxygenase enzyme that forms 3-methylcatechol with concomitant release of nitrite. The 3-methylcatechol is subsequently degraded via the meta ring fission pathway.     

Complete genome sequence of Paenibacillus sp. strain JDR-2

Paenibacillus sp. strain JDR-2, an aggressively xylanolytic bacterium isolated from sweetgum (Liquidambar styraciflua) wood, is able to efficiently depolymerize, assimilate and metabolize 4-O-methylglucuronoxylan, the predominant structural component of hardwood hemicelluloses. A basis for this capability was first supported by the identification of genes and characterization of encoded enzymes and has been further defined by the sequencing and annotation of the complete genome, which we describe. In addition to genes implicated in the utilization of β-1,4-xylan, genes have also been identified for the utilization of other hemicellulosic polysaccharides. The genome of Paenibacillus sp. JDR-2 contains 7,184,930 bp in a single replicon with 6,288 protein-coding and 122 RNA genes. Uniquely prominent are 874 genes encoding proteins involved in carbohydrate transport and metabolism. The prevalence and organization of these genes support a metabolic potential for bioprocessing of hemicellulose fractions derived from lignocellulosic resources.     

Biodegradation of chlorpyrifos and its hydrolyzing metabolite 3,5,6-trichloro-2-pyridinol by Sphingobacterium sp. JAS3

Biodegradation of chlorpyrifos and its metabolite 3,5,6-trichloro-2-pyridinol (TCP) were studied in aqueous medium and in soil with a novel bacterial strain JAS3. The molecular characterization based on 16S rRNA sequence analysis revealed the strain JAS3 as Sphingobacterium sp. The strain JAS3 was able to grow in minimal salt medium (MSM) supplemented with 300 mg l^?1 of chlorpyrifos as sole carbon source. The degradation of chlorpyrifos and its primary metabolite TCP were examined by HPLC. After 5 d, Sphingobacterium sp. JAS3 degraded chlorpyrifos and its metabolite TCP to benzene, 1,3-bis(1,1-dimethylethyl) was analyzed by GCMS. Degradation of chlorpyrifos and TCP in soil with and without addition of nutrients was also studied. The ability to degrade chlorpyrifos makes this strain a useful candidate for remediation of pesticide contaminated sites.     

假单胞菌S-2降解甲胺磷性能的研究

从甲胺磷生产车间分离到一株假单胞菌编号为S-2。S-2可利用甲胺磷为唯一氮源,但不能利用甲胺磷为唯一磷源。该文对S-2体内具有的降解甲胺磷的酶类进行了研究,初步断定：S-2可代谢产生酸性磷酸酶,主要在胞外降解甲胺磷。S-2在甲胺磷诱导的情况下,这些降解酶类可大量聚积。用诱导过的菌液降解甲胺磷比未经诱导的快了2d左右。     

Biodegradation of 4-chlorophenol by entrappedAlcaligenes sp. A 7-2

Summary The degradation of 4-chlorophenol by free and by Ca-alginate-immobilized cells ofAlcaligenes sp. A 7-2 has been studied. Increasing concentrations of 4-chlorophenol (0.4–0.55 mM) were better tolerated and more quickly degraded by the immobilized organisms than by free cells. The capability for haloarene-degradation is inducible. In semicontinuous fermentation at pH 7 a minimal degradation time of 5 h for degrading 0.2 mM 4-chlorophenol was reached. Fermentation temperature was shown to be important for inducing the degradation capability, but to be less important for the degradation rate by induced organisms. High-frequency feeding of small amounts of 4-chlorophenol (0.05 mM) was more favourable than low-frequency feeding of larger amounts (0.15 mM).Continuous fermentation with unbuffered medium allowed a degradation rate of about 2 mmol·l^-1·d^-1; with buffered medium a higher degradation rate of nearly 4 mmol·l^-1·d^-1 was reached, but the Ca-alginate beads dissolved.     

Biodegradation of p-toluenesulphonamide by a Pseudomonas sp.

A bacterium capable of utilising p-toluenesulphonamide was isolated from activated sludge. The isolated strain designated PTSA was identified as a Pseudomonas sp. using chemotaxonomic and genetic studies. Pseudomonas PTSA grew on p-toluenesulphonamide in a chemostat with approximately 90% release of sulphate and 80% release of ammonium. The isolate was also able to grow on 4-carboxybenzenesulphonamide and 3,4-dihydroxybenzoate but did not grow on p-toluenesulphonate. The transient appearance of 4-hydroxymethylbenzenesulphonamide and 4-carboxybenzenesulphonamide during p-toluenesulphonamide degradation proves oxidation of the methyl group is the initial attack in the biodegradation pathway. Both metabolites of p-toluenesulphonamide degradation were identified by high-performance liquid chromatography-mass spectrometry. 4-Carboxybenzenesulphonamide is probably converted into 3,4-dihydroxybenzoate and amidosulphurous acid. The latter is a chemically unstable compound in aqueous solutions and immediately converted into sulphite and ammonium. Both sulphite and ammonium were formed during degradation of 4-carboxybenzenesulphonamide.     

Biodegradation of malachite green by Ochrobactrum sp.

This study presents the biodegradation of malachite green (MG), a triphenylmethane dye, using a novel microorganism isolated from textile effluent contaminated environment. The organism responsible for degradation was identified as Ochrobactrum sp JN214485 by 16S rRNA analysis. The effect of operating parameters such as temperature, pH, immobilized bead loading, and initial dye concentration on % degradation was studied, and their optimal values were found to be 30 °C, 6, 20 g/L and 100 mg/L, respectively. The analysis showed that the extracellular enzymes were responsible for the degradation. The biodegradation of MG was confirmed by UV–visible spectroscopic and FTIR analysis. The phytotoxicity test concluded that the degradation products were less toxic compared to MG. The kinetics of biodegradation was studied and the activation energy was found to be 10.65 kcal/mol.     

Biodegradation of nicotine by newly isolated Pseudomonas sp. CS3 and its metabolites

Aims: Isolation and characterization of nicotine‐degrading bacteria with advantages suitable for the treatment of nicotine‐contaminated water and soil and detection of their metabolites. Methods and Results: A novel nicotine‐degrading bacterial strain was isolated from tobacco field soil. Based on morphological and physiochemical properties and sequence of 16S rDNA, the isolate was identified as Pseudomonas sp., designated as CS3. The optimal culture conditions of strain CS3 for nicotine degradation were 30°C and pH 7·0. However, the strain showed broad pH adaptability with high nicotine‐degrading activity between pH 6·0 and 10·0. Strain CS3 could decompose nicotine nearly completely within 24 h in liquid culture (1000 mg L^?1 nicotine) or within 72 h in soil (1000–2500 mg kg^?1 nicotine) and could endure up to 4000 mg L^?1 nicotine in liquid media and 5000 mg kg^?1 nicotine in soil. Degradation tests in flask revealed that the strain had excellent stability and high degradation activity during the repetitive degradation processes. Additionally, three intermediates, 3‐(3,4‐dihydro‐2H‐pyrrol‐5‐yl) pyridine, 1‐methyl‐5‐(3‐pyridyl) pyrrolidine‐2‐ol and cotinine, were identified by GC/MS and NMR analyses. Conclusions: The isolate CS3 showed outstanding nicotine‐degrading characteristics such as high degradation efficiency, strong substrate endurance, broad pH adaptability, and stability and persistence in repetitive degradation processes and may serve as an excellent candidate for applications in the bioaugmentation process to treat nicotine‐contaminated water and soil. Also, detection of nicotine metabolites suggests that strain CS3 might decompose nicotine via a unique nicotine‐degradation pathway. Significance and Impact of the Study: The advantage of applying the isolated strain lies in broad pH adaptability and stability and persistence in repetitive use, the properties previously less focused in other nicotine‐degrading micro‐organisms. The strain might decompose nicotine via a nicotine‐degradation pathway different from those of other nicotine‐utilizing Pseudomonas bacteria reported earlier, another highlight in this study.     

Mucoromycotina sp. HS-3对苯胺蓝染料的降解

采用静置开敞式培养法研究了碳源、氮源、盐度、金属离子对Mucoromycotina sp.HS-3菌降解苯胺蓝的影响。结果表明,菌株脱色最适合条件为葡萄糖1 g/L,硫酸铵0.6 g/L,Fe3+0.15 mmol/L,盐度小于50 g/L,在上述各培养条件下,对浓度为100 mg/L不灭菌的苯胺蓝溶液静止培养5 d,脱色率达95%以上。此外,通过降解前后的苯胺蓝溶液对豇豆和枯草芽孢杆菌进行毒性测试发现,降解后的苯胺蓝溶液毒性明显降低。因此,该菌对处理以苯胺蓝为主要成分的印染废水具有较好的应用潜力。     

Biodegradation of diphenyl ether and its monohalogenated derivatives by Sphingomonas sp. strain SS3.

The bacterium Sphingomonas sp. strain SS3, which utilizes diphenyl ether and its 4-fluoro, 4-chloro, and (to a considerably lesser extent) 4-bromo derivatives as sole sources of carbon and energy, was enriched from soil samples of an industrial waste deposit. The bacterium showed cometabolic activities toward all other isomeric monohalogenated diphenyl ethers. During diphenyl ether degradation in batch culture experiments, phenol and catechol were produced as intermediates which were then channeled into the 3-oxoadipate pathway. The initial step in the degradation follows the recently discovered mechanism of 1,2-dioxygenation, which yields unstable phenolic hemiacetals from diphenyl ether structures. Oxidation of the structure-related dibenzo-p-dioxin yielded 2-(2-hydroxyphenoxy)-muconate upon ortho cleavage of the intermediate 2,2',3-trihydroxydiphenyl ether. Formation of phenol, catechol, halophenol, and halocatechol from the conversion of monohalogenated diphenyl ethers gives evidence for a nonspecific attack of the dioxygenating enzyme system.     

Biodegradation of diphenyl ether and its monohalogenated derivatives by Sphingomonas sp. strain SS3.

The bacterium Sphingomonas sp. strain SS3, which utilizes diphenyl ether and its 4-fluoro, 4-chloro, and (to a considerably lesser extent) 4-bromo derivatives as sole sources of carbon and energy, was enriched from soil samples of an industrial waste deposit. The bacterium showed cometabolic activities toward all other isomeric monohalogenated diphenyl ethers. During diphenyl ether degradation in batch culture experiments, phenol and catechol were produced as intermediates which were then channeled into the 3-oxoadipate pathway. The initial step in the degradation follows the recently discovered mechanism of 1,2-dioxygenation, which yields unstable phenolic hemiacetals from diphenyl ether structures. Oxidation of the structure-related dibenzo-p-dioxin yielded 2-(2-hydroxyphenoxy)-muconate upon ortho cleavage of the intermediate 2,2',3-trihydroxydiphenyl ether. Formation of phenol, catechol, halophenol, and halocatechol from the conversion of monohalogenated diphenyl ethers gives evidence for a nonspecific attack of the dioxygenating enzyme system.     

Biodegradation of exploded cotton stalk by Bacillus sp.

The exploded bast, branch and stem of cotton stalk were degraded by alkalophilic Bacillus NT-19, with weight losses of 24%, 20% and 14%, respectively, after 14 d. Compared with a white-rot fungus (Phanerochaete chrysosporium), Bacillus NT-19 preferentially degraded the non-cellulose components of cotton stem. The relative degree of crystallinity of bast fibers decreased by 8% and the middle lamella was partially removed from the fiber bundle by the Bacillus.     

Biodegradation of 2,4-dinitrotoluene by a Pseudomonas sp.

Previous studies of the biodegradation of nonpolar nitroaromatic compounds have suggested that microorganisms can reduce the nitro groups but cannot cleave the aromatic ring. We report here the initial steps in a pathway for complete biodegradation of 2,4-dinitrotoluene (DNT) by a Pseudomonas sp. isolated from a four-member consortium enriched with DNT. The Pseudomonas sp. degraded DNT as the sole source of carbon and energy under aerobic conditions with stoichiometric release of nitrite. During induction of the enzymes required for growth on DNT, 4-methyl-5-nitrocatechol (MNC) accumulated transiently in the culture fluid when cells grown on acetate were transferred to medium containing DNT as the sole carbon and energy source. Conversion of DNT to MNC in the presence of 18O2 revealed the simultaneous incorporation of two atoms of molecular oxygen, which demonstrated that the reaction was catalyzed by a dioxygenase. Fully induced cells degraded MNC rapidly with stoichiometric release of nitrite. The results indicate an initial dioxygenase attack at the 4,5 position of DNT with the concomitant release of nitrite. Subsequent reactions lead to complete biodegradation and removal of the second nitro group as nitrite.     

Biodegradation of 2,4-dinitrotoluene by a Pseudomonas sp.

Previous studies of the biodegradation of nonpolar nitroaromatic compounds have suggested that microorganisms can reduce the nitro groups but cannot cleave the aromatic ring. We report here the initial steps in a pathway for complete biodegradation of 2,4-dinitrotoluene (DNT) by a Pseudomonas sp. isolated from a four-member consortium enriched with DNT. The Pseudomonas sp. degraded DNT as the sole source of carbon and energy under aerobic conditions with stoichiometric release of nitrite. During induction of the enzymes required for growth on DNT, 4-methyl-5-nitrocatechol (MNC) accumulated transiently in the culture fluid when cells grown on acetate were transferred to medium containing DNT as the sole carbon and energy source. Conversion of DNT to MNC in the presence of 18O2 revealed the simultaneous incorporation of two atoms of molecular oxygen, which demonstrated that the reaction was catalyzed by a dioxygenase. Fully induced cells degraded MNC rapidly with stoichiometric release of nitrite. The results indicate an initial dioxygenase attack at the 4,5 position of DNT with the concomitant release of nitrite. Subsequent reactions lead to complete biodegradation and removal of the second nitro group as nitrite.     

Biodegradation of the sulfonylurea herbicide chlorimuron-ethyl by the strain Pseudomonas sp. LW3

Eleven carbazole (CAR)-degrading bacterial strains were isolated from seawater collected off the coast of Japan using two different media. Seven isolates were shown to be most closely related to the genera Erythrobacter, Hyphomonas, Sphingosinicella, Caulobacter , and Lysobacter . Meanwhile, strains OC3, OC6S, OC9, and OC11S showed low similarity to known bacteria, the closest relative being Kordiimonas gwangyangensis GW14-5 (90% similarity). Southern hybridization analysis revealed that only five isolates carried car genes similar to those reported in Pseudomonas resinovorans CA10 ( car _CA10) or Sphingomonas sp. strain KA1 ( car _KA1). The isolates were subjected to GC-MS and the results indicated that these strains degrade CAR to anthranilic acid.     

Biodegradation of tributyl phosphate using Klebsiella pneumoniae sp. S3

Tributyl phosphate (TBP) has enormous applications in the field of extraction, fuel reprocessing, as defoamers and/or plasticizers. Excessive usage of this organophosphorus compound, poses an environmental threat. The present study deals with microbial degradation of TBP using Klebsiella pneumoniae S3 isolated from the soil. Diauxic growth curve pattern explains a preferential utilization of TBP. The strain S3 was able to biotransform TBP (1,000 mg L^?1) to dibutyl phosphate within 48 h and showed higher tolerance towards TBP up to 17.0 g L^?1. Toxicity of the parent as well as degraded product was assessed using comet assay. Generation of reactive oxygen species elaborates the oxidative stress imposed upon the bacterial strain by TBP. The antioxidant defense mechanism was studied using various biomarkers namely catalase, glutathione-S-transferase, and superoxide dismutase. The present study describes a faster and eco-friendly alternative for disposal of TBP.