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In the present study the produced biosurfactant of Acinetobacter junii B6 (recently isolated from Iranian oil excavation site) were partially purified and identified by high performance thin layer chromatography (HPTLC), Fourier transform infrared spectroscopy (FTIR), and proton nuclear magnetic resonance ( 1 H NMR). Elemental analysis of the biosurfactant by energy dispersive X-ray spectroscopy (EDS) revealed that the biosurfactant was anionic in nature. The physiochemical properties of the lipopeptide biosurfactant were evaluated by determination of its critical micelle concentration (CMC) and hydrophile-lipophile balance (HLB). The produced biosurfactant decreased the surface tension of water to 36 mN m −1 with the CMC of approximately 300 mg/l. Furthermore, the solubility properties of the biosurfactant (dissolved in phosphate-buffer saline solution, pH 7.4) were investigated by turbidity examination, dynamic light scattering (DLS) measurements, and transmission electron microscopy (TEM) inspection. It could be concluded that the biosurfactant showed the spherical-shaped vesicles at a concentration higher than its CMC and the circular dichroism (CD) spectra showed that the secondary structure of the biosurfactant vesicles is dominated by the β sheet. [ABSTRACT FROM AUTHOR]

Rhizoremediation is considered as an environmentally friendly technique to deal with the contamination of petroleum hydrocarbons. The current study was aimed at checking the potential of indigenous micro-organisms isolated from rhizosphere soil being irrigated by the wastewater of petroleum refinery to degrade benzene efficiently. For this study, soil samples were taken from the discharge point of oil refinery located in Rawalpindi, Pakistan, by brushing off the soil from roots ofCannabis sativa. The soil was processed for isolation of indigenous microbial strains. Sixteen bacterial strains isolated from the soil were screened for their potential to grow using benzene as sole carbon sourcein vitro. These were exposed initially to 250 mg L−1followed by 500 and 750 mg L−1of benzene, where only seven strains were able to survive with optical density (OD600) of ≥1.1. Three better performing strains with OD600 > 1.6 were further subjected to degrade 1,000 mg L−1benzene (sole carbon source) using M9 media. The community diversity analysis for the best performing strains was carried out using 16S ribosomal RNA.Pseudomonas aeruginosa(SAR-1) was the best degrader with 85% benzene degradation in 72 hours followed byBacillus cereus(SAR-2) andAcinetobacter junii(SAR-3) with 83 and 70% efficiency, respectively. To the best of our knowledge,A. junii(SAR-3) is being reported as a benzene degrader for the first time. [ABSTRACT FROM PUBLISHER]

A marine, gram negative, rod shaped bacterium that degrades agar was isolated from the east coast of India and was identified to be Acinetobacter junii PS12B based on 16S rRNA gene sequencing. The effect of different culture conditions, namely pH of the medium, time and temperature of incubation and the agar concentration in the medium, on the agarase production by the strain, was evaluated. The agarase production was significantly ( p <0.05) affected by the culture conditions. The optimum conditions as determined by response surface methodology were found to be a temperature of 35 °C, pH of 7.0 and time of fermentation of 33 h and agar concentration of 0.5%. Under the optimum conditions, the isolate produced 0.17 units of agarase per ml of the medium. Ammonium nitrate and sodium nitrate were the best nitrogen source in the medium for agarase production by the isolate. Supplementing the agar containing minimal media with simple sugars like glucose and galactose was found to enhance agarase production significantly by two fold. The isolate was also able to degrade carrageenan, which indicates its role in utilization of marine polysaccharides for the production of bioactive oligosaccharides. [ABSTRACT FROM AUTHOR]

Abstract: The immobilization of desired bacteria onto material was usually performed in synthetic media. The aim of this study was to test the immobilization of phosphate (P)-accumulating bacteria Acinetobacter junii onto natural zeolitized tuff (NZ) in the raw or sterilized municipal wastewater containing the common bacteria Escherichia coli and Enterococcus faecalis and the performance of immobilized A. junii in the same type of wastewater. In the sterilized wastewater which contained the mixture of A. junii, E. coli and E. faecalis, the A. junii was selectively immobilized onto NZ in significantly higher numbers than E. coli and E. faecalis. The A. junii added in the form of bioparticles to the wastewater containing E. coli and E. faecalis, multiplied and removed P from wastewater. The P removal from wastewater was a function of biomass of P-accumulating bacteria and not the amount of NZ or bioparticles used. The performance of A. junii was significantly better in membrane filtered than in autoclaved wastewater. The experiments that were performed in raw non sterilized wastewater showed that A. junii can be successfully immobilized onto NZ in competition with natively present heterotrophic bacteria, retain its metabolic activity and successfully remove P from such water, which makes this technology feasible from biotechnological aspect. [Copyright &y& Elsevier]

Abstract: The genus Acinetobacter is an important causative pathogen of nosocomial infections in the healthcare setting. The objectives of this study were to determine the species of causative pathogens and the sources of Acinetobacter blood stream infections that occurred in 2 immunocompetent pregnant women admitted to an obstetrics ward within a 2-month period. Phenotypic identification of the two isolates from blood stream infections was inconsistent among the ID test, the MicroScan WalkAway and the Vitek2 systems. In addition to the growth profile and detailed biochemical analysis, genotypic identification and phylogenetic tree analysis based on the almost complete 16S rRNA sequence and the partial rpoB gene sequence confirmed the identification of these isolates as A. ursingii. Environmental investigation of the obstetrics ward revealed A. ursingii and different strains of Acinetobacter junii in specimens obtained from the ward shower bath, although the source and route of transmission for the A. ursingii infections were not clarified. Our findings show that A. ursingii can inhabit the hospital environment. [Copyright &y& Elsevier]

Abstract: Hemicellulose, accounting for up to 30% of lignocellulose, could play an important role in producing cellulosic bioenergy. Xylanase is the key enzyme capable of hydrolyzing hemicellulose to form fermentable five-carbon sugars for biofuel production. A cellulolytic bacterial strain isolated from soil in southern Taiwan is able to produce xylanase and cellulase extracellularly with a high efficiency. The xylanase produced by the isolated strain (identified as Acinetobacter junii F6-02) exhibits the highest activity at 60°C and pH 7.0. However, the best condition for producing xylanase by the F6-02 strain was 35°C and pH 7.0 using BHM medium supplemented with CMC (5g/L), xylan (5g/L), and peptone (1g/L). Fermentative production of xylanase was greatly influenced by oxygen supply, reaching the highest level at an aeration rate of 0.3vvm. The highest cumulative xylanase production and xylanase production rate was 317U/ml and 8.06U/ml/h, respectively. The lyophilized cellulolytic enzymes produced from A. junii F6-02 display better enzyme activity than the original crude enzyme extract and are able to perform long-term hydrolysis stably at a temperature of 50°C. [ABSTRACT FROM AUTHOR]

Abstract: Sepiolite in its original (OS) and purified form (PS) was tested as a carrier of the phosphate-accumulating bacteria Acinetobacter junii. The numbers of A. junii immobilized onto sepiolite were 5.57 and 8.12×109 CFUg−1 for OS and PS, respectively. The immobilized bacteria were metabolically active and removed phosphate from synthetic wastewater. Better phosphate removal in reactors with immobilized bacteria when compared to reactors with planktonic bacteria was mainly due to the increased bacterial biomass and at a lower extent due to the increased bacterial phosphate-uptake rates. The bioaugmentation of an activated sludge with A. junii immobilized on OS significantly improved the phosphate removal from synthetic wastewater when compared to a conventional activated sludge. [ABSTRACT FROM AUTHOR]

Abstract: Three different forms of perlite (non-expanded, semi-expanded and expanded) were tested as carriers of phosphate-accumulating bacterium Acinetobacter junii. The highest rate of immobilization of A. junii (12.65×109 CFUg−1) was obtained for expanded perlite, followed by semi-expanded (5.57×109 CFUg−1) and non-expanded (1.68×109 CFUg−1) perlite. The number of immobilized A. junii on expanded perlite was the highest among all carriers of Acinetobacter species reported in the literature so far. The immobilization of A. junii on perlite was dependent on the particle size, but not on the zeta potential of particles. The SSA of the perlite samples influenced immobilization of A. junii but was not recognized as the crucial factor. Immobilized bacteria were metabolically active and successfully removed phosphate from the wastewater when incubated in pure culture or in bioaugmented activated sludge. In the system with activated sludge the best carrier of A. junii was the semi-expanded perlite which was well incorporated in the sludge. The expanded perlite was floating on the surface of the wastewater while raw perlite sunk to the bottom of the reactor, diminishing the exposure and consequently phosphate removal of immobilized bacteria in the wastewater. [ABSTRACT FROM AUTHOR]

Abstract: Xylan and rice straw were used to produce H2 via a two-stage approach combining feedstock pretreatment/hydrolysis and dark H2 fermentation. Acinetobacter junii F6-02 was used to produce cellulolytic enzymes (mainly xylanase) to hydrolyze xylan and pretreated rice straw. The hydrolysates were converted to H2 by Clostridium butyricum CGS5 via dark fermentation. Investigation of kinetics of xylanase on xylan and NaOH-pretreated rice straw shows ν max values of 8.6 and 3.6g/L/h, and Km values of 10.6 and 26.9g/L, respectively. A maximum hydrogen production rate of 62.5 and 26.8ml/h/L was obtained from hydrolysate of xylan and pretreated rice straw, respectively, while the hydrogen yield was 0.70 and 0.76mol H2/mol xylose, respectively. Simultaneous saccharification and BioH2 fermentation from xylan was also conducted but giving a lower hydrogen production rate (35.3ml/h/L) than that of the two-stage process. [Copyright &y& Elsevier]

Abstract: The ability of non-flocculating Acinetobacter spp. isolates (A. johnsonii S35 and A. junii S33) to coaggregate with other sludge-constituting bacteria obtained from a sewage sludge sample was assessed by a spectrophotometric assay. A. johnsonii S35 showed significant coaggregation (aggregation index (AI)=70 to 99%) with 7 strains, Bacillus cereus, Blastomonas natatoria, Mycobacterium sp., Thermomonas brevis, and Enterobacteriaceae family, identified by sequencing of 16S rRNA genes. A. junii S33 coaggregated with 4 strains, which were also coaggregating partners of A. johnsonii S35, as indicated by AI values of 59–93%. The microbial adhesion to hydrocarbon (MATH) assay showed that both A. johnsonii S35 and A. junii S33 possess a hydrophobic character as indicated by their relative cell surface hydrophobicity (RCSH), 88 and 61%, respectively. A good correlation was observed between the degree of coaggregation of the Acinetobacter spp. isolates and the RCSH of their partner strains. The cells of an A. johnsonii S35 spontaneous mutant and A. johnsonii IAM1517, which had a hydrophilic cell surface, did not coaggregate with the other examined isolates. These results demonstrated that hydrophobic interaction plays an important role in the intergeneric coaggregation of Acinetobacter spp. isolates with other sludge-constituting bacteria. [Copyright &y& Elsevier]

Acinetobacter junii SY-01 producing a lipase enantioselectively hydrolyzing 1,3-dioxolane derivatives was isolated from water sludge sample and the effect of solvent, acyl donor, vinyl acetate concentration, substrate concentration, operating temperature and immobilization on activity and enantioselectivity was studied for the resolution of 1,3-dioxolane derivatives through transesterification reaction using a lipase from the isolated strain. Best selectivity was obtained at lower substrate concentration (3–5mM), higher vinyl acetate concentration (500–1000mM) and lower temperature (30–40°C) in the reaction mixture. Lipase immobilized onto Accurel MP-1000 (micro-porous polypropylene) gave the best results and the reactivity was about 29-fold higher than the free enzyme without the decrease of enantioselectivity. Resolution of 1,3-dioxolane derivatives was carried out in flask scale containing 100ml solvents using the lipase immobilized onto Accurel MP-1000. In this reaction, the yield and enantiomeric excess of the remaining (2R, 4S)-alcohol were 31.2% and 98.2%, respectively. This result suggests that it can be used as an alternative method, compared to the present synthetic method, for the production of optically pure (2R, 4S)-itraconazole. [Copyright &y& Elsevier]