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molecular characterization of an n-alkane-degrading bacterial community and identification of a new species, acinetobacter venetianus.twenty-five bacterial strains isolated from the venice lagoon and implicated in the degradation of n-alkanes, n-alkanols, n-alkanals and n-alkanoates were characterized in molecular and physiological terms. the isolates were grouped by amplified ribosomal dna restriction analysis (ardra) into seven clusters, corresponding to seven species, six of which were identified on the basis of 16s rdna sequencing. genetic variability among strains was shown by random amplified polymorphic dna (rapd). only ...19979765804
oil-degrading acinetobacter strain rag-1 and strains described as 'acinetobacter venetianus sp. nov.' belong to the same genomic species.acinetobacter strain rag-1 (atcc 31012) is an industrially important strain which has been extensively characterized with respect to its growth an hydrocarbons and its production of a high molecular mass bioemulsifier, emulsan. although rag-1 has been investigated in detail for specific biochemical characteristics, its taxonomic status is uncertain and it is usually referred to as a. lwoffii or a. calcoaceticus sensu lato. however, results obtained by restriction analysis of the amplified rdna a ...199910096135
adhesion of acinetobacter venetianus to diesel fuel droplets studied with in situ electrochemical and molecular probesthe adhesion of a recently described species, acinetobacter venetianus ve-c3 (f. di cello, m. pepi, f. baldi, and r. fani, res. microbiol. 148:237-249, 1997), to diesel fuel (a mixture of c12 to c28 n-alkanes) and n-hexadecane was studied and compared to that of acinetobacter sp. strain rag-1, which is known to excrete the emulsifying lipopolysaccharide, emulsan. oxygen consumption rates, biomass, cell hydrophobicity, electrophoretic mobility, and zeta potential were measured for the two strains ...199910223998
an exocellular protein from the oil-degrading microbe acinetobacter venetianus rag-1 enhances the emulsifying activity of the polymeric bioemulsifier emulsan.the oil-degrading microorganism acinetobacter venetianus rag-1 produces an extracellular polyanionic, heteropolysaccharide bioemulsifier termed emulsan. emulsan forms and stabilizes oil-water emulsions with a variety of hydrophobic substrates. removal of the protein fraction yields a product, apoemulsan, which exhibits much lower emulsifying activity on hydrophobic substrates such as n-hexadecane. one of the key proteins associated with the emulsan complex is a cell surface esterase. the esteras ...200312732528
long-term analysis of diesel fuel consumption in a co-culture of acinetobacter venetianus, pseudomonas putida and alcaligenes faecalis.the dynamics of a microbial population isolated from superficial waters of venice lagoon and the ability to utilise diesel fuel (n-alkanes mixture c12-c28) as the sole carbon and energy source were studied in a long-term reconstruction experiment. the reconstructed microbial population consisted of three bacterial strains belonging to the species acinetobacter venetianus, pseudomonas putida, and alcaligenes faecalis, which were able to oxidise n-alkanes to alkanoates, n-alkanols to alkanoates, o ...200312755474
envelope glycosylation determined by lectins in microscopy sections of acinetobacter venetianus induced by diesel fuel.it was suggested in a previous study that cells of acinetobacter venetianus ve-c3 adhere to diesel fuel by synthesizing a capsular polysaccharide containing glucose and/or mannose. to study the fine structure of cells and localization of bacterial polysaccharide in the presence of diesel fuel, two lectins were used: cona, an agglutinin from canavalia ensiformis specific for mannose and/or glucose residues, and pna, an agglutinin from arachis hypogaea, for terminal galactose residues. the lectins ...200312892848
alcanivorax which prevails in oil-contaminated seawater exhibits broad substrate specificity for alkane degradation.alcanivorax is an alkane-degrading marine bacterium which propagates and becomes predominant in crude-oil-containing seawater when nitrogen and phosphorus nutrients are supplemented. in order to understand why alcanivorax overcomes other bacteria under such cultural conditions, competition experiments between alcanivorax indigenous to seawater and the exogenous alkane-degrading marine bacterium, acinetobacter venetianus strain t4, were conducted. when oil-containing seawater supplemented with ni ...200312919410
the concentrations of hexadecane and inorganic nutrients modulate the production of extracellular membrane-bound vesicles, soluble protein, and bioemulsifier by acinetobacter venetianus rag-1 and acinetobacter sp. strain ho1-n.in the present study, we addressed the possibility that the production of both bioemulsifiers and membrane-bound vesicles may be a common feature of the growth of acinetobacter spp. on alkanes, and we determined the extent to which the release of extracellular products by these organisms is regulated by the concentrations of the alkane substrate and inorganic nutrients. to accomplish this objective, we grew acinetobacter venetianus rag-1 and acinetobacter sp. strain ho1-n with different concentr ...200314608423
emulsan quantitation by nile red quenching fluorescence assay.a nile red fluorescent technique to quantify 20-200 microg ml(-1) of emulsan was developed. nile red dissolved in dmso showed an adsorption peak at 552 nm, and emission peak at 636 nm, with molar extinction coefficient of 19,600 cm(-1) m(-1). nile red fluorescence in dmso was proportionally quenched by emulsan and the quenching was time-dependent. the assay was used to follow the production of emulsan by cultures of acinetobacter venetianus rag-1.200415614556
novel polysaccharide-protein-based amphipathic formulations.previous results showed that the cell-surface esterase from acinetobacter venetianus rag-1 enhances the emulsification properties of the polymeric bioemulsifier emulsan and its deproteinated derivative apoemulsan (bach h, berdichevsky y, gutnick d (2003) an exocellular protein from the oil-degrading microbe acinetobacter venetianus rag-1 enhances the emulsifying activity of the polymeric bioemulsifier emulsan. appl environ microbiol 69:2608-2615). here we show that in the presence of the his-tag ...200616172888
a unique polypeptide from the c-terminus of the exocellular esterase of acinetobacter venetianus rag-1 modulates the emulsifying activity of the polymeric bioemulsifier apoemulsan.an exocellular esterase from the oil-degrading acinetobacter venetianus rag-1 was previously shown to enhance the emulsification and emulsion stabilization properties of the amphipathic, aminopolysaccharide bioemulsifier, emulsan [bach h, berdichevsky y, gutnick d (2003) an exocellular protein from the oil-degrading microbe acinetobacter venetianus rag-1 enhances the emulsifying activity of the polymeric bioemulsifier emulsan. appl environ microbiol 69:2608-15]. this enhancement was specific for ...200616237525
utilization of n-alkanes by a newly isolated strain of acinetobacter venetianus: the role of two alkb-type alkane hydroxylases.a bacterial strain capable of utilizing n-alkanes with chain lengths ranging from decane (c10h22) to tetracontane (c40h82) as a sole carbon source was isolated using a system for screening microorganisms able to grow on paraffin (mixed long-chain n-alkanes). the isolate, identified according to its 16s rrna sequence as acinetobacter venetianus, was designated a. venetianus 6a2. two dna fragments encoding parts of alkb-type alkane hydroxylase homologues, designated alkma and alkmb, were polymeras ...200616520925
biosynthesis of emulsan biopolymers from agro-based feedstocks.the need for biocompatible, biodegradable, and versatile biopolymers permeates many fields including environmental and food technology. the goal of the study presented here is to establish the utility of agricultural oils as an inexpensive carbon source to produce materials useful for biomedical materials and offer positive attributes in terms of green chemistry.200717241359
protein engineering of wzc to generate new emulsan analogs.acinetobacter venetianus rag1 produces an extracellular, polymeric lipoheteropolysaccharide termed apoemulsan. this polymer is putatively produced via a wzy-dependent pathway. according to this model, the length of the polymer is regulated by polysaccharide-copolymerase (pcp) protein. a highly conserved proline and glycine motif was identified in all members of the pcp family of proteins and is involved in regulation of polymer chain length. in order to control the structure of apoemulsan, defin ...200717449706
mechanical properties of hexadecane-water interfaces with adsorbed hydrophobic bacteria.this study focuses on how intact, hydrophobic bacteria in their stationary (i.e., non-dividing) phase could adsorb onto the hexadecane-water interface and alter its mechanical properties. the two strains of bacteria used in forming the interfacial films were acinetobacter venetianus rag-1 and rhodococcus erythropolis 20s-e1-c. using the dynamic pendant drop technique, the film interfacial tension was monitored as the surface area was made to undergo transient changes. under static conditions, bo ...200818093811
construction of a chimeric gene cluster for the biosynthesis of apoemulsan with altered molecular weight.acinetobacter venetianus rag-1 produces an extracellular protein/high-molecular-weight (hmw) polysaccharide complex termed emulsan. as an emulsion stabilizer, emulsan has potential industrial applications. to control the molecular weight of the polymer, a stable chromosomal mutant was generated where rag-1 wza, wzb, wzc genes were replaced by escherichia coli homologs. the heterologous wza, wzb, wzc proteins restored production of hmw polysaccharide. the polymer produced was of higher molecular ...200818239917
atomic force microscopy measurement of heterogeneity in bacterial surface hydrophobicity.the structure and physicochemical properties of microbial surfaces at the molecular level determine their adhesion to surfaces and interfaces. here, we report the use of atomic force microscopy (afm) to explore the morphology of soft, living cells in aqueous buffer, to map bacterial surface heterogeneities, and to directly correlate the results in the afm force-distance curves to the macroscopic properties of the microbial surfaces. the surfaces of two bacterial species, acinetobacter venetianus ...200818355095
discovery of the dual polysaccharide composition of emulsan and the isolation of the emulsion stabilizing component.emulsan has been reported as an emulsion stabilizing amphipathic lipoheteropolysaccharide secreted by the oil-degrading bacterium acinetobacter venetianus rag-1. previously, emulsan was regarded as a single polymer. as a result of developing a new purification process, we have discovered that emulsan is a complex of approximately 80% (w/w) lipopolysaccharide (lps) and 20% (w/w) high molecular weight exopolysaccharide (eps). the eps was purified to 98% (w/w) using tangential flow filtration, trit ...200818547107
transesterification activity of a novel lipase from acinetobacter venetianus rag-1.transesterification activity and the industrial potential of a novel lipase prepared from acinetobacter ventiatus rag-1 were evaluated. purified lipase samples were dialyzed against ph 9.0 buffer in a single optimization step prior to lyophilization. the enzyme and organic phase were pre-equilibrated (separately) to the same thermodynamic water activities (a (w)) ranging from a (w) 0.33 to 0.97. production of 1-octyl butyrate by lipase-catalyzed transesterification of vinyl butyrate with 1-octan ...200818720025
hydrophobic bacteria at the hexadecane-water interface: examination of micrometre-scale interfacial properties.hydrophobic bacteria, like colloidal solids, can spontaneously adsorb onto fluid-fluid interfaces and modify their mechanical properties. in this study, two strains of bacteria--acinetobacter venetianus rag-1 and rhodococcus erythropolis 20s-e1-c--were prepared in their stationary (i.e. non-dividing) phase in the absence of biosurfactants; the cells were then used as emulsifiers to stabilize n-hexadecane droplets in aqueous environments. using the micropipette technique, colloidal stability of t ...200818778923
modifications and applications of the acinetobacter venetianus rag-1 exopolysaccharide, the emulsan complex and its components.since its discovery in the late 1970s, emulsan has been the subject of significant interest for fundamental biosynthesis and structure-function relationships as well as for its potential industrial applications. these studies initially examined the emulsification properties of the compound, while more recent efforts have focused on potential biomedical applications. as a result of this change of focus, it became necessary to more completely characterize the structure of the emulsan molecule and ...200818795287
influence of deletions in the apoemulsan gene cluster on a. venetianus rag-1 polysaccharide biosynthesis.apoemulsan is a biopolymer with potent emulsification activity, produced by acinetobacter venetianus rag-1 (rag-1). the wee gene cluster is responsible for apoemulsan biosynthesis. the analysis of (i) a putative polysaccharide copolymerase mutant (wzc), (ii) a putative polymerase mutant (wzy), and (iii) an apoemulsan-deficient variant (2) indicated that the wee gene cluster controls the synthesis of two polysaccharides: high molecular weight (hmw) and low molecular weight (lmw). lmw polysacchari ...200819131689
optimizing emulsan production of a. venetianus rag-1 using response surface methodology.statistical experimental design was used to optimize medium constituents for emulsan production by acinetobacter venetianus rag-1 in batch cultivation. the factors affecting emulsan production were screened by a two-level factorial design, and the optimal concentration of medium constituents for emulsan production were determined by the method of steepest path ascent and central composite experimental design. experimental results showed that the optimal medium constituents were 9.16 g/l ethanol, ...200919326114
analysis of force interactions between afm tips and hydrophobic bacteria using dlvo theory.microbial adhesion to surfaces and interfaces is strongly influenced by their structure and physicochemical properties. we used atomic force microscopy (afm) to measure the forces between chemically functionalized afm tips and two bacterial species exhibiting different cell surface hydrophobicities, measured as the oil/water contact angle (theta): acinetobacter venetianus rag-1 (theta = 56.4 degrees ) and rhodococcus erythropolis 20s-e1-c (theta = 152.9 degrees ). the forces were measured as the ...200919334745
description of acinetobacter venetianus ex di cello et al. 1997 sp. nov.the name 'acinetobacter venetianus' has been used previously to designate three marine hydrocarbon-degrading acinetobacter strains, of which strain rag-1 (=atcc 31012) has industrial applications for the production of the bioemulsifier emulsan. however, to date, the name of this taxon has not been validly published. in this study, five strains were examined to corroborate the delineation of this taxon by means of phenotypic characterization, dna-dna hybridization, selective restriction fragment ...200919502319
bio-generated metal binding polysaccharides as catalysts for synthetic applications and organic pollutant transformations.iron and palladium binding an exopolysaccharide (eps) were obtained and purified from cultures of bacterial cells of klebsiella oxytoca bas-10. the strain bas-10 was able to grow under anaerobic conditions with fe(iii)-citrate as energy and carbon source, producing fe(iii)-eps that was extracted and used as catalyst in the oxidation reaction of phenol with h(2)o(2). the same bacterial strain was cultivated anaerobically with na-citrate and pd(2)(no)(3) was added during the exponential growth to ...201121616180
acinetobacter sp. hm746599 isolated from leatherback turtle blood.a newly described bacterial isolate, acinetobacter sp. hm746599, has been obtained from leatherback sea turtle hatchling blood. the implication is that the hatchling was infected during development in the egg, which is substantiated by other studies to be reported by us in the future. the 16s rrna gene sequence of the bacterium (genbank accession number: hm746599) showed the greatest similarity to the identified species, acinetobacter beijerinckii (97.6-99.78%) and acinetobacter venetianus (99.7 ...201121707734
molecular and phenotypic characterization of acinetobacter strains able to degrade diesel fuel.characterization of bacterial communities in oil-contaminated soils and evaluation of their degradation capacities may serve as a guide for improving remediation of such environments. using physiological and molecular methods, the aim of this work was to characterize 17 acinetobacter strains (13 species) able to use diesel fuel oil as sole carbon and energy source. the strains were first tested for their ability to grow on different alkanes on minimal medium containing high nacl concentrations. ...201122210401
Biodegradation of medium chain hydrocarbons by Acinetobacter venetianus 2AW immobilized to hair-based adsorbent mats.The natural attenuation of hydrocarbons can be hindered by their rapid dispersion in the environment and limited contact with bacteria capable of oxidizing hydrocarbons. A functionalized composite material is described herein, that combines in situ immobilized alkane-degrading bacteria with an adsorbent material that collects hydrocarbon substrates, and facilitates biodegradation by the immobilized bacterial population. Acinetobacter venetianus 2AW was isolated for its ability to utilize hydroph ...201121948333
draft genome sequence of the hydrocarbon-degrading and emulsan-producing strain acinetobacter venetianus rag-1t.we report the draft genome sequence of acinetobacter venetianus strain rag-1(t), which is able to degrade hydrocarbons and to synthesize a powerful biosurfactant (emulsan) that can be employed for oil removal and as an adjuvant for vaccine delivery. the genome sequence of a. venetianus rag-1(t) might be useful for bioremediation and/or clinical purposes.201222887671
gene cloning and characterization of a cold-adapted esterase from acinetobacter venetianus v28.acinetobacter venetians v28 was isolated from the intestine of righteye flounder, poecilopsetta plinthus caught in vietnam seawater, and the esterase gene was cloned using a shotgun method. the amino acid sequence deduced from the nucleotide sequence (1,017 bp) corresponded to a protein of 338 amino acid residues with a molecular weight of 37,186. the esterase had 87% and 72% identities with the lipases of a. junii sh205 and a. calcoaceticus ruh2202, respectively. the esterase contained a putati ...201222814499
immobilization of whole cells by chemical vapor deposition of silica.effective entrapment of whole bacterial cells onto solid-phase materials can significantly improve bioprocessing and other biotechnology applications. cell immobilization allows integration of biocatalysts in a manner that maintains long-term cell viability and typically enhances process output. a wide variety of functionalized materials have been explored for microbial cell immobilization, and specific advantages and limitations were identified. the method described here is a simple, versatile, ...201323934813
the genome sequence of the hydrocarbon-degrading acinetobacter venetianus ve-c3.here we report the genome sequence of acinetobacter venetianus ve-c3, a strain isolated from the venice lagoon and known to be able to degrade n-alkanes. post sequencing analyses revealed that this strain is relatively distantly related to the other acinetobacter strains completely sequenced so far as shown by phylogenetic analysis and pangenome analysis (1285 genes shared with all the other acinetobacter genomes sequenced so far). a. venetianus ve-c3 possesses a wide range of determinants whose ...201323528645
transcriptomic analysis of the highly efficient oil-degrading bacterium acinetobacter venetianus rag-1 reveals genes important in dodecane uptake and utilization.the hydrocarbonoclastic bacterium acinetobacter venetianus rag-1 has attracted substantial attention due to its powerful oil-degrading capabilities and its potential to play an important ecological role in the cleanup of alkanes. in this study, we compare the transcriptome of the strain rag-1 grown in dodecane, the corresponding alkanol (dodecanol), and sodium acetate for the characterization of genes involved in dodecane uptake and utilization. comparison of the transcriptional responses of rag ...201627664055
genomic and phenotypic characterization of the species acinetobacter venetianus.crude oil is a complex mixture of hydrocarbons and other organic compounds that can produce serious environmental problems and whose removal is highly demanding in terms of human and technological resources. the potential use of microbes as bioremediation agents is one of the most promising fields in this area. members of the species acinetobacter venetianus have been previously characterized for their capability to degrade n-alkanes and thus may represent interesting model systems to implement ...201626902269
draft genome sequence of alkane-degrading acinetobacter venetianus jksf02, isolated from contaminated sediment of the san jacinto river in houston, texas.acinetobacter venetianusjksf02 was isolated from contaminated sediment in eastern houston, texas along the san jacinto river. this microorganism specializes in n-alkane degradation and is well suited for bioremediation of the petroleum hydrocarbon deposited throughout the region by shipping and industrial activity from the houston ship channel.201627081144
remediation of water contaminated with diesel oil using a coupled process: biological degradation followed by heterogeneous fenton-like oxidation.the treatment of a synthetically prepared wastewater containing diesel oil has been investigated using combined treatment schemes based on the biological treatment followed by an advanced oxidation process. 78% of diesel oil was degraded by acinetobacter venetianus in 96 h, while the removal efficiency of chemical oxygen demand (cod) in the aqueous phase was only 56.8%, indicating that degraded metabolites existed in solution. to solve this problem, a fenton-like system consisting of nanoscale z ...201728551205
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