Enhanced Biodegradation of Alkane Hydrocarbons and Crude Oil by Mixed Strains and Bacterial Community Analysis

In this study, two strains, Acinetobacter sp. XM-02 and Pseudomonas sp. XM-01, were isolated from soil samples polluted by crude oil at Bohai offshore. The former one could degrade alkane hydrocarbons (crude oil and diesel, 1:4 (v/v)) and crude oil efficiently; the latter one failed to grow on alkane hydrocarbons but could produce rhamnolipid (a biosurfactant) with glycerol as sole carbon source. Compared with pure culture, mixed culture of the two strains showed higher capability in degrading alkane hydrocarbons and crude oil of which degradation rate were increased from 89.35 and 74.32?±?4.09 to 97.41 and 87.29?±?2.41 %, respectively. In the mixed culture, Acinetobacter sp. XM-02 grew fast with sufficient carbon source and produced intermediates which were subsequently utilized for the growth of Pseudomonas sp. XM-01 and then, rhamnolipid was produced by Pseudomonas sp. XM-01. Till the end of the process, Acinetobacter sp. XM-02 was inhibited by the rapid growth of Pseudomonas sp. XM-01. In addition, alkane hydrocarbon degradation rate of the mixed culture increased by 8.06 to 97.41 % compared with 87.29 % of the pure culture. The surface tension of medium dropping from 73.2?×?10^?3 to 28.6?×?10^?3 N/m. Based on newly found cooperation between the degrader and the coworking strain, rational investigations and optimal strategies to alkane hydrocarbons biodegradation were utilized for enhancing crude oil biodegradation.     

Rosigenin,an unusual metabolite from mycosphaerella rosigena1

A new metabolite, 3,6-dimethyl-4,10-dihydroxy-2-oxaspiro[4.5]dec-7-en-1,9-dione (1a), was isolated from a strain of Mycosphaerella rosigena grown on potato-agar medium. The structure was determined on the basis of chemical and spectroscopic evidence and confirmed by X-ray analysis.     

Synthesis and characterization of some carbazole-based imine polymers

Five imine polymers, all containing 3,6-disubstituted carbazole ring in the main polymer chain, were synthesized by solution polycondensation of 3,6-diformyl (N-hexyl) carbazole with hydrazine, 1,4-diaminobenzene, 4,4′-diaminobiphenyl, 1,5-diaminonaphthalene and 3,6-(N-hexyl) diaminocarbazole. The polymers were analyzed by spectroscopic methods and compared with two imine models.     

Copper(II) catalyzed aromatization of tetrahydrocarbazole: An unprecedented protocol and its utility towards the synthesis of carbazole alkaloids

An efficient protocol for the aromatization of tetrahydrocarbazole is described by using catalytic copper(II) chloride dihydrate in DMSO. This newly established methodology has utilized towards the synthesis of naturally occurring carbazole alkaloids, namely 3-methylcarbazole, 3-formyl carbazole, glycozoline, glycozolicine and clauszoline-K. In addition, the protocol is generalized for the aromatization of N-substituted tetrahydrocarbazole, 1,2,3,4-tetrahydroquinoline, 1,2,3,4-tetrahydroisoquinoline and 1,2,3,4-tetrahydro β-carboline to give the corresponding heteroaromatic compounds from very good to excellent yield. Moreover, this method has been proven to be tolerant to a broad range of functional groups with excellent yields.     

Biodegradation analyses of trichloroethylene (TCE) by bacteria and its use for biosensing of TCE

Trichloroethylene (TCE) is a toxic, recalcitrant groundwater pollutant. TCE-degrading microorganisms were isolated from various environments. The aerobic bacteria isolated from toluene- and tryptophan-containing media were Pseudomonas sp. strain ASA86 and Burkholderia sp. strain TAM17, respectively; these are necessary for inducing TCE biodegradation in a selective medium. The half-degradation time of TCE to a concentration of 1 mg/L was 18 h for strain ASA86 and 7 days for strain TAM17. While identifying toluene/TCE degradation genes, we found that in strain ASA86, the gene was the same as the todC1 gene product encoding toluene dioxygenase identified in Pseudomonas putida F1, and that in strain TAM17, the gene was similar to the tecA1 gene product encoding chlorobenzene dioxygenase identified in Burkholderia sp. PS12. A novel TCE biosensor was developed using strain ASA86 as the inducer of toluene under aerobic conditions. The TCE biosensor exhibited a linear relationship below 3 ppm TCE. Detection limit of the biosensor was 0.05 ppm TCE. The response time of the biosensor was less than 10 min. The biosensor response displayed a constant level during a 2 day period. The TCE biosensor displayed sufficient sensitivity for monitoring TCE in environmental systems.     

Parameters influencing the molecular weight of 3,6‐carbazole‐based D‐π‐A‐type copolymers

Condensation copolymerization reactions of carbazole 3,6‐diboronate with 4,7‐bis(5‐bromo‐2‐thienyl)‐2,1,3‐benzothiadiazole (DTBT) only produce low‐molecular‐weight donor (D)‐π‐acceptor (A) copolymers. High‐molecular‐weight copolymers for use in optoelectronic devices are necessary for achieving extended π‐conjugation and for controlling the copolymer processibility. To elucidate the cause of the persistently low molecular weight, we synthesized three 3,6‐carbazole‐based D‐A copolymers using copolymerizations of N‐9′‐heptadecanyl‐3,6‐carbazole with DTBT, N‐9′{2‐[2‐(2‐methoxy‐ethoxy)‐ethoxy]‐ethyl}‐3,‐6‐carbazole with DTBT, and N‐9′‐heptadecanyl‐3,6‐carbazole with alkyl‐substituted DTBT. We investigated several parameters for their influence on molecular copolymer weight, including the conformation of the chain during growth, the solubility of the monomers, and the dihedral angles between the donor and acceptor units. Size exclusion chromatography, UV–vis absorption spectroscopy, and computational studies revealed that the low molecular weights of 3,6‐carbazole‐based D‐A copolymers resulted from conjugation breaks and the resulting high coplanarity, which led to strong interactions between polymer chains. These interactions limited formation of high‐molecular‐weight‐copolymers during copolymerization. The strong intermolecular interactions of the 3,6‐carbazole moiety were exploited by incorporating 3,6‐carbazole units into poly[9′,9′‐dioctyl‐2,7‐flourene‐alt‐5,5‐(4′,7′‐di‐2‐thienyl‐2′,1′,3′‐benzothiadiazole)] prepared from 9′,9′‐dioctyl‐2,7‐flourene and DTBT. Interestingly, the number average molecular weight increased gradually with increasing 2,7‐fluorene monomer content but the number of conjugation breaks was a range of 6–7. The hole mobilities of the copolymers were studied for comparison purposes. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Intrinsic Characteristics of Cr6+-Resistant Bacteria Isolated from an Electroplating Industry Polluted Soils for Plant Growth-Promoting Activities

The Cr⁶⁺-resistant plant growth-promoting bacteria was isolated from soil samples that were collected from an electroplating industry at Coimbatore, India, that had tolerated chromium concentrations up to 500?mg Cr⁶⁺/L in Luria-Bertani medium. Based on morphology, physiology, and biochemical characteristics, the strain was identified as Bacillus sp. following the Bergey's manual of determinative bacteriology. Evaluation of plant growth-promoting parameters has revealed the intrinsic ability of the strain for the production of indole-3-acetic acid (IAA), siderophore, and solubilization of insoluble phosphate. Bacillus sp. have utilized tryptophan as a precursor for their growth and produced IAA (122???g/mL). Bacillus sp. also exhibited the production of siderophore that was tested qualitatively using Chrome Azurol S (CAS) assay solution and utilized the insoluble tricalcium phosphate as the sole source of phosphate exhibiting higher rate of phosphate solubilization after 72?h of incubation (1.45???g/mL). Extent of Cr⁶⁺ uptake and accumulation of Cr⁶⁺ in the cell wall of Bacillus sp. was investigated using atomic absorption spectrophotometer and scanning electron microscope-energy dispersive spectroscopy, respectively. The congenital capability of this Cr⁶⁺-resistant plant growth-promoting Bacillus sp. could be employed as bacterial inoculum for the improvement of phytoremediation in heavy metal contaminated soils.     

Synthesis of η6‐(4a‐Methyl‐1,2,3,4‐tetrahydro‐4aH‐carbazole)‐tricarbonylchromium complex and stereoelectronic behaviour with organolithium reagents: an apparent frontal attack to the (CO)3Cr group

The synthesis of η⁶‐(4a‐methyl‐1,2,3,4‐tetrahydro‐4aH‐carbazole)tricarbonylchromium ( 3 ) is described, and its reactivity with organolithium reagents have been analysed. The addition of RLi (R= H, Me, n‐Bu, tert‐Bu) to 3 affords the corresponding endo/exo tricarbonylchromium complexes of cis‐4a‐methyl‐9a‐substituted‐1,2,3,4‐tetrahydro‐4aH‐carbazole, which permit the consideration of the stereoelectronic behaviour of the tricarbonylchromium group on 4a‐methyl and the 9a substituent or on the methylenes of the cyclohexene moiety in the complexes.     

The preparation and some chemistry of 2,2-dimethyl-1,2-dihydroquinolines

The cyclisation of N-(1,1-dimethylpropargyl) anilines, using cuprous chloride in refluxing toluene, yields 6-substituted-2,2-dimethyl-1,2-dihydroquinolines. The reactivity of the double bond in the heterocyclic ring of these products is exemplified by chlorination, to yield 6-substituted-3,4-cis-dichloro-2,2-dimethyl-1,2,3,4-tetrahydroquinolines which can be selectively dechlorinated to provide 6-substituted-3-chloro-2,2-dimethyl-1,2,3,4-tetrahydroquinolines; epoxidation to yield an epoxide, which can be hydrogenolysed to the corresponding 3-hydroxy product and in turn oxidised to the 3-keto derivative; and oxymercuration to provide a 4-hydroxy product and hence a 4-keto derivative. Dehydrochlorination of a 3,4-dichloro product provides a 3-chloro-1,2-dihydroquinoline which can be hydrolysed to a 3-keto system. The formation of cis 3,4-dichloro products from the chlorination, as well as the formation of a cis chlorohydrin from the chlorination of N-acetyl-2,2,6-trimethyl-1,2-dihydroquinoline in partially aqueous solution, suggests that N-acetyl, or N-trifluoroacetyl groups, participate in the addition process.     

Conformational flexibility of 4,4-dimethyl-3,4-dihydro-2H-1,4-thiasiline and its monoheterocyclic analogs

Conformational behavior of the first cyclic organosilicon vinylsulfide, 4,4-dimethyl-3,4-dihydro-2H-1,4-thiasiline as well as its monoheterocyclic analogs, 3,4-dihydro-2H-pyran, 3,4-dihydro-2H-thiopyran, and 1,1-dimethyl-1,2,3,4-tetrahydrosiline is studied in comparison with the carbocyclic analog, cyclohexene, using the methods of low-temperature NMR spectroscopy and theoretical calculations at the DFT and MP2 levels of theory. The barrier to the ring inversion with respect to that in cycloxene is increased in 3,4-dihydro-2H-pyran and 1,1-dimethyl-1,2,3,4-tetrahydrosiline, but, in contrast to the suggestions made in the literature, is decreased in 3,4-dihydro-2H-thiopyran. In 4,4-dimethyl-3,4-dihydro-2H-1,4-thiasiline the barrier is intermediate between those in the corresponding monoheterocycles, 1,1-dimethyl-1,2,3,4-tetrahydrosiline and 3,4-dihydro-2H-thiopyran. The observed variations are rationalized from the viewpoint of the interaction of the π-electrons of the C=C double bond with the orbitals of heteroatoms in the ring. The structure of the transition state for the ring inversion is discussed.     

Degradation of Triclosan under Aerobic, Anoxic, and Anaerobic Conditions

Triclosan (2, 4, 4??-trichloro-2??-hydroxyl diphenyl ether) is a broad-spectrum antimicrobial agent present in a number of house hold consumables. Aerobic and anaerobic enrichment cultures tolerating triclosan were developed and 77 bacterial strains tolerating triclosan at different levels were isolated from different inoculum sources. Biodegradation of triclosan under aerobic, anoxic (denitrifying and sulphate reducing conditions), and anaerobic conditions was studied in batch cultures with isolated pure strains and enrichment consortium developed. Under aerobic conditions, the isolated strains tolerated triclosan up to 1?g/L and degraded the compound in inorganic-mineral-broth and agar media. At 10?mg/L level triclosan, 95?±?1.2% was degraded in 5?days, producing phenol, catechol and 2, 4-dichlorophenol as the degradation products. The strains were able to metabolize triclosan and its degradation products in the presence of monooxygenase inhibitor 1-pentyne. Under anoxic/anaerobic conditions highest degradation (87%) was observed in methanogenic system with acetate as co-substrate and phenol, catechol, and 2, 4-dichlorophenol were among the products. Three of the isolated strains tolerating 1?g/L triclosan were identified as Pseudomonas sp. (BDC 1, 2, and 3).     

Complete mineralization of methylparathion by Pseudomonas sp. A3

Organophosphorus insecticides are widely used in agriculture. Despite their biodegradable nature, some are highly toxic and their residues are found in the environment. Reports on the mineralization of a spectrum of these insecticides by a single potential strain are scarce. We have isolated a soil isolate, Pseudomonas sp. A3, through enrichment technique, able to degrade methylparathion (MP), malathion, monocrotophos, and Diazinon. The potential of this strain to mineralize MP as a carbon and/or phosphorus source has been evaluated. On hydrolysis of MP, the aromatic portion (p-nitrophenol) was used as a carbon and energy source whereas the alkyl moiety (dithiomethylphosphorothioate) was broken down for the phosphorus source. The results from the experiments involving [U-¹⁴C]p-nitrophenol provided the evidence for incorporation of carbon into the cellular constituents and release of CO₂ from this insecticide. During the breakdown of MP, nitrite was released as a catabolic by-product.     

Two-Stage Cultivation of Pseudomonas sp. F12 for the Production of Enzymes Converting dl-2-Amino-Δ2-thiazoline-4-carboxylic Acid to l-Cysteine

Pseudomonas sp. F12 isolated from soil could transform dl-2-amino-??²-thiazoline-4-carboxylic acid (DL-ATC) to l-cysteine. It could grow in minimal medium containing DL-ATC as the sole carbon and nitrogen source, and the apparent activity of l-cysteine synthesis (CS) achieved 122?U/mL in a 5-L bioreactor. Pseudomonas sp. F12 could utilize glucose as carbon source and ammonia as nitrogen source for growth, but no CS activity was formed. To reduce the cost of DL-ATC, the cultivation process was divided into a growth stage on glucose and ammonia and a production stage induced by DL-ATC. The excessive glucose led to the production of byproduct(s) which seriously inhibited cell growth and CS production. Ammonium was accumulated when DL-ATC was consumed, and ammonium did not inhibit CS activity formation until 60?mM. Based on the above features, fed-batch cultivation of the growth stage was developed by supplying glucose restrictively. The volumetric CS activity was enhanced more than two times that obtained under the initial conditions.     

Reactions of 2,3-dioxopyrrolo[2,1-<Emphasis Type="Italic">a</Emphasis>]isoquinolinecarboxylic acid esters and amides with nitrogen-centered nucleophiles

Reactions of ethyl 2,3-dioxopyrrolo[2,1-a]isoquinoline-1-carboxylates with active nitrogen-centered nucleophiles (phenylhydrazine, hydroxylamine, and benzylamine) involve opening of the pyrrole ring with formation of 2-(3,3-dimethyl-1,2,3,4-tetrahydroisoquinolin-1-ylidene)-N′¹,N′⁴-diphenyl-3-(2-phenylhydrazono) succinohydrazide, 5-(6,7-dimethoxy-3,3-dimethyl-1,2,3,4-tetrahydroisoquinolin-1-ylidene)-2,3,4,5-tetrahydro-1H-1,2-oxazine-3,4,6-trione, and ethyl 4-benzylamino-2-(3,3-dimethyl-1,2,3,4-tetrahydroisoquinolin-1-ylidene)-3,4-dioxobutanoate, respectively. Cyclic amides derived from 5,5-dimethyl-2,3-dioxo-2,3,5,6-tetrahydropyrrolo[2,1-a]isoquinoline-1-carboxylic acid react with benzylamine in a similar way. Reactions of the title compounds with weaker nucleophiles, such as semicarbazide and thiosemicarbazide, are not accompanied by opening of the pyrrole ring, and the products are the corresponding semicarbazones and thiosemicarbazones at the C²=O carbonyl group.     

Optical and electroluminescent properties of novel poly(aryl ether)s with isolated carbazole and p‐quaterphenyl fluorophores

We report the optical and electroluminescent properties of four novel poly(aryl ether)s ( P1 – P4 ) consisting of alternate isolated hole‐transporting [carbazole or 3,6‐bis(styryl)carbazole] and electron‐transporting [dicyano‐p‐quaterphenyl or bis(trifluoromethyl)‐p‐quaterphenyl] fluorophores. The photoluminescence (PL) spectra of the four polymeric films show maximum peaks around 407–413 nm for P1 , P2 and 442–447 nm for P3 , P4 . The PL spectra of P1 ～ P4 are dependent on the composition of the two isolated fluorophores. According to the observation of relative quantum yield in poor solvent (cyclohexane), P2 containing more bulky trifluoromethyl groups in p‐quaterphenyl segments prevented aggregate quenching processes more than P1 . Compared with P1 and P2 with carbazole segments, P3 and P4 with 3,6‐bis(styryl)carbazole segments exhibited less interchain interaction and a low threshold electric field in a single‐layer device. The p‐quaterphenyl and carbazole [or 3,6‐bis(styryl)carbazole] segments were regarded as electron‐transporting and hole‐transporting units, respectively, in the single‐layer light‐emitting diodes (Al/ P1 – P4 /ITO). In the double‐layer device (ITO/MEH‐PPV/ P2 /Al), the maximum luminance was doubled, and the threshold electric fields diminished because P2 functioned as an electron‐transporting and hole‐blocking layer. Furthermore, the voltage‐tunable multicolor emission from orange to green was observed. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 333–340, 2004     

Highly Effective Inactivation of Pseudomonas sp HB1 in Water By Atmospheric Pressure Microplasma Jet Array

By using an atmospheric pressure microplasma jet array device driven by a.c. voltage with repetition rate of several kilohertz, we were able to inactivate the resistant Pseudomonas sp HB1 cells in aqueous solution. Measurements showed that all Pseudomonas sp. cells in a suspension of 80?mL with the concentration of ~10⁸ CFU (Colony-Forming Units) were killed within a treatment time of 6?min. Rather than O radicals, OH radicals or charged species were supposed to play the most important role in the plasma inactivation process by this method. This design can provide an effective mode of killing the resistant microorganism in water.     

A photochemical synthesis of 11H-benzo[a]carbazole

11H-Benzo[a]carbazole was prepared from 5-acetamido-1,2,3,4-tetrahydronaphthalene in four steps. A Goldberg arylation followed by hydrolysis afforded N-phenyl-1,2,3,4-tetrahydro-5-naphthylarnine ( 3 ). Photolysis of 3 produced 1,2,3,4-tetrahydro-11H-benzo[a]carbazole ( 4 ) which was converted to 11H-benzo[a]-carbazole by dehydrogenation with chloranil.     

1,8-diamino-3,6-dichlorocarbazole: a promising building block for anion receptors

[reaction: see text] Advantages of the carbazole moiety as a new skeleton for the construction of anion receptors are illustrated by two model amide receptors derived from 1,8-diamino-3,6-dichlorocarbazole.     

Isolation, Screening, and Optimization of the Fermentation Conditions of Highly Cellulolytic Bacteria from the Hindgut of Holotrichia parallela Larvae (Coleoptera: Scarabaeidae)

From the hindgut contents of Holotrichia parallela, 93 cellulolytic bacterial isolates were isolated after enrichment in carboxymethyl cellulose medium. Among these isolates, a novel bacterium, designated HP207, with the highest endoglucanase productivity was selected for further study. This bacterium was identified as Pseudomonas sp. based on the results of the 16S ribosomal DNA analysis, morphological characteristics, and biochemical properties. The production of the endoglucanase was optimized by varying various physical culture conditions using a submerged fermentation method. Under the optimized fermentation conditions, the maximum endoglucanase activity of 1.432?U?mL^?1 in bacterial cultures was obtained, higher than those of the most widely studied bacteria and fungi, which are the attractive candidates for the commercial producer of cellulase. And the crude endoglucanase enzyme was also highly thermostable; approximately 55?% of the original activity was maintained after pretreatment at 70?°C for 1?h. Thus, from the present study, the bacterium can be added up to the database of cellulolytic bacteria.     

Biosynthetic access to the rare antiarose sugar via an unusual reductase-epimerase

Rubrolones, isatropolones, and rubterolones are recently isolated glycosylated tropolonids with notable biological activity. They share similar aglycone skeletons but differ in their sugar moieties, and rubterolones in particular have a rare deoxysugar antiarose of unknown biosynthetic provenance. During our previously reported biosynthetic elucidation of the tropolone ring and pyridine moiety, gene inactivation experiments revealed that RubS3 is involved in sugar moiety biosynthesis. Here we report the in vitro characterization of RubS3 as a bifunctional reductase/epimerase catalyzing the formation of TDP-d-antiarose by epimerization at C3 and reduction at C4 of the key intermediate TDP-4-keto-6-deoxy-d-glucose. These new findings not only explain the biosynthetic pathway of deoxysugars in rubrolone-like natural products, but also introduce RubS3 as a new family of reductase/epimerase enzymes with potential to supply the rare antiarose unit for expanding the chemical space of glycosylated natural products.

Rubrolones, isarubrolones, and rubterolones are recently isolated glycosylated tropolonids with notable biological activity.