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Frontiers in Microbiology 2016Biosurfactant producers are crucial for incremental oil production in microbial enhanced oil recovery (MEOR) processes. The isolation of biosurfactant-producing bacteria...
Biosurfactant producers are crucial for incremental oil production in microbial enhanced oil recovery (MEOR) processes. The isolation of biosurfactant-producing bacteria from oil reservoirs is important because they are considered suitable for the extreme conditions of the reservoir. In this work, a novel biosurfactant-producing strain BD was isolated from a reservoir to reduce surface tension and emulsify crude oil. The biosurfactants produced by the strain were purified and then identified via electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR-MS). The biosurfactants generated by the strain were concluded to be rhamnolipids, the dominant rhamnolipids were CHO, CHO, and CHO. The optimal carbon source and nitrogen source for biomass and biosurfactant production were NaNO and soybean oil. The results showed that the content of acid components increased with the progress of crude oil biodegradation. A glass micromodel test demonstrated that the strain significantly increased oil recovery through interfacial tension reduction, wettability alteration and the mobility of microorganisms. In summary, the findings of this study indicate that the newly developed BD strain and its metabolites have great potential in MEOR.
PubMed: 27872613
DOI: 10.3389/fmicb.2016.01710 -
Bioresource Technology Oct 2015Acinetobacter junii YB was found to exhibit efficient heterotrophic nitrification and aerobic denitrification ability, with the maximum ammonium, nitrite and nitrate...
Nitrogen removal characteristics of a heterotrophic nitrifier Acinetobacter junii YB and its potential application for the treatment of high-strength nitrogenous wastewater.
Acinetobacter junii YB was found to exhibit efficient heterotrophic nitrification and aerobic denitrification ability, with the maximum ammonium, nitrite and nitrate removal rate of 8.82, 8.45 and 7.98 mg/L/h, respectively. Meanwhile, ammonium was found to be removed preferentially in the process of simultaneous nitrification and denitrification in mixed N-sources. The successful PCR amplification of hao, napA and nirS genes further provided additional evidence of heterotrophic nitrification and aerobic denitrification by strain YB. In addition, orthogonal test showed that dissolved oxygen was the most important determinant of nitrite removal, and the optimal conditions were C/N 15, pH 7.0, 37 °C and 200 rpm. Furthermore, stable nitrogen and organics removal were achieved by one-time dosing of enriched bacteria in a sequencing batch reactor. The inoculation of strain YB significantly improved the denitrification efficiency with minimal accumulation of nitrified products, which demonstrated high potential of the isolate for future practical applications.
Topics: Acinetobacter; Aerobiosis; Ammonium Compounds; Denitrification; Heterotrophic Processes; Hydrogen-Ion Concentration; Nitrates; Nitrification; Nitrites; Nitrogen; Oxygen; Temperature; Wastewater
PubMed: 26141282
DOI: 10.1016/j.biortech.2015.05.075 -
Journal of Global Antimicrobial... Jun 2023Colistin-resistant Gram-negative pathogens have become a serious worldwide medical problem. This study was designed to reveal the effects of an intrinsic...
OBJECTIVES
Colistin-resistant Gram-negative pathogens have become a serious worldwide medical problem. This study was designed to reveal the effects of an intrinsic phosphoethanolamine transferase from Acinetobacter modestus on Enterobacterales.
METHODS
A strain of colistin-resistant A. modestus was isolated from a sample of nasal secretions taken in 2019 from a hospitalised pet cat in Japan. The whole genome was sequenced by next generation sequencing, and transformants of Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae harbouring the phosphoethanolamine transferase-encoding gene from A. modestus were constructed. Lipid A modification in E. coli transformants was analysed using electrospray ionization mass spectrometry.
RESULTS
Sequencing of the entire genome revealed that the isolate harboured a phosphoethanolamine transferase-encoding gene, eptA_AM, on its chromosome. Transformants of E. coli, K. pneumoniae, and E. cloacae harbouring both the promoter and eptA_AM gene from A. modestus had 32-fold, 8-fold, and 4-fold higher minimum inhibitory concentrations (MICs) for colistin, respectively, than transformants harbouring a control vector. The genetic environment surrounding eptA_AM in A. modestus was similar to that surrounding eptA_AM in Acinetobacter junii and Acinetobacter venetianus. Electrospray ionization mass spectrometry analysis revealed that EptA_AM modified lipid A in Enterobacterales.
CONCLUSION
This is the first report to describe the isolation of an A. modestus strain in Japan and show that its intrinsic phosphoethanolamine transferase, EptA_AM, contributes to colistin resistance in Enterobacterales and A. modestus.
Topics: Animals; Cats; Colistin; Escherichia coli; Lipid A; Ethanolaminephosphotransferase; Bacterial Proteins; Drug Resistance, Bacterial; Anti-Bacterial Agents; Klebsiella pneumoniae
PubMed: 36906175
DOI: 10.1016/j.jgar.2023.02.023 -
Journal of Medical Microbiology May 2018The aim of this study was to characterize the presence of carbapenemase-encoding genes in distinct species of Acinetobacter spp. isolated from Brazilian hospitals. Five...
The aim of this study was to characterize the presence of carbapenemase-encoding genes in distinct species of Acinetobacter spp. isolated from Brazilian hospitals. Five carbapenem-resistant Acinetobacter spp. isolates (two Acinetobacter pittii, two Acinetobacter bereziniae and one Acinetobacter junii) recovered from two distinct hospitals between 2000 and 2016 were included in this study. All of the isolates harboured blaIMP-1, which was inserted into In86, a class 1 integron. Pulsed field gel eletrophoresis analysis showed that both A. pittii were identical, while the two A. berezinae isolates were considered to be clonally related. In this study, we demonstrated that mobile elements carrying carbapenemase-encoding genes such as In86 may persist for a long period, allowing their mobilization from A. baumannii to other Acinetobacter spp. that are usually susceptible to multiple antimicrobials.
Topics: Acinetobacter; Acinetobacter Infections; Bacterial Proteins; Brazil; Carbapenems; Humans; Integrons; beta-Lactamases
PubMed: 29624159
DOI: 10.1099/jmm.0.000732 -
Quorum sensing in metal tolerance of Acinetobacter junii BB1A is associated with biofilm production.FEMS Microbiology Letters May 2008Acinetobacter junii strain BB1A, a novel metal-tolerant bacterium, produced biofilm in the presence of added ions such as Ni(2+), AsO(2)(-), Cd(2+) and Hg(2+) on...
Acinetobacter junii strain BB1A, a novel metal-tolerant bacterium, produced biofilm in the presence of added ions such as Ni(2+), AsO(2)(-), Cd(2+) and Hg(2+) on surfaces such as glass and polystyrene. Generation of a metal-sensitive and adhesion-deficient mutant by transposition of Tn5-mob in the A. junii genome has putatively confirmed the association of metal tolerance with the production of biofilm. The requirement of a critical cell density for biofilm formation and presence of acyl-homoserine lactone-like autoinducer molecules in the cell-free supernatant indicated the phenomenon of quorum sensing. Addition of a natural quorum-sensing inhibitor (garlic extract) or synthetic quorum-sensing inhibitor (4-nitro-pyridine oxide) significantly inhibited cell growth and biofilm formation in the presence of metal/metalloid ions.
Topics: 4-Butyrolactone; Acinetobacter; Biofilms; Drug Tolerance; Gene Expression Regulation, Bacterial; Metals; Quorum Sensing; Signal Transduction
PubMed: 18397291
DOI: 10.1111/j.1574-6968.2008.01080.x -
Journal of Applied Microbiology Apr 2019The aims of the study were to (i) isolate and characterize arsenic-tolerant bacterial strains, (ii) study the plant growth-promoting traits and (iii) explore their...
AIMS
The aims of the study were to (i) isolate and characterize arsenic-tolerant bacterial strains, (ii) study the plant growth-promoting traits and (iii) explore their bioremediation potential.
METHODS AND RESULTS
Indigenous arsenic hypertolerant bacterial isolates NM02 and NM03 were screened as they were capable of growing at 150 mmol l As (V) and 70 mmol l As (III). They were identified on the basis of morphological, physiological and biochemical parameter and 16sDNA sequence as Bacillus flexus and Acinetobacter junii respectively. Genomic DNA analysis for the investigation of ars operon revealed the presence of metalloregulatory arsC gene, suggesting their ability to detoxify arsenic. The analysis for siderophore, phosphate solubilization, indole acetic acid (IAA) and ACC deaminase highlighted the intrinsic plant growth-promoting rhizobacteria traits of both the bacterial strains. The energy dispersive spectroscopy analysis proved the potential of cellular arsenic sequestration within the strains. Moreover, Fourier-transform infrared spectra revealed the repositioning of the spectral bands in As presence, indicating the presence of those functional groups on the bacterial surface that is involved in As adsorption.
CONCLUSIONS
Our results indicate that bacterial strains NM02 and NM03 were identified as potent applicants for arsenic bioremediation and possess the ability to facilitate plant growth.
SIGNIFICANCE AND IMPACT OF THE STUDY
The bacterial strains are proficient in As detoxification and can be employed for arsenic bioremediation; a cost-effective and in situ remediation technique for the polluted soil.
Topics: Acinetobacter; Adaptation, Physiological; Arsenic; Bacillus; Bacterial Proteins; Biodegradation, Environmental; Plant Growth Regulators; RNA, Ribosomal, 16S; Soil Microbiology; Soil Pollutants
PubMed: 30556924
DOI: 10.1111/jam.14179 -
International Journal of Biological... Jun 2018In the present study the produced biosurfactant of Acinetobacter junii B6 (recently isolated from Iranian oil excavation site) were partially purified and identified by...
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 (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 36mNm with the CMC of approximately 300mg/l. Furthermore, the solubility properties of the biosurfactant (dissolved in phosphate-buffer saline solution, pH7.4) 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.
Topics: Acinetobacter; Chromatography, Thin Layer; Circular Dichroism; Erythrocytes; Hemolysis; Humans; Hydrophobic and Hydrophilic Interactions; Lipopeptides; Protein Aggregates; Proton Magnetic Resonance Spectroscopy; Rheology; Spectrometry, X-Ray Emission; Spectrophotometry, Ultraviolet; Spectroscopy, Fourier Transform Infrared; Surface Tension; Surface-Active Agents; Temperature; Thermogravimetry
PubMed: 29425877
DOI: 10.1016/j.ijbiomac.2018.01.209 -
Applied Biochemistry and Biotechnology Jan 2022Mastitis is a widespread disease in dairy cattle occurring throughout the world. The increased use of antibiotics brings about the development of antibiotic-resistant...
Mastitis is a widespread disease in dairy cattle occurring throughout the world. The increased use of antibiotics brings about the development of antibiotic-resistant microbes. The application of antibiotics in dairy farming led to increased antibiotic resistance and represents a major obstacle for the treatment of mastitis. Recent advancements in nanotechnology led to the development of nanocolloids to overcome disadvantages posed by conventional antimicrobial agents. Hence, a novel, environmentally friendly, cost-effective, biocompatible, and long-term antibacterial represents a promising solution for medicine and farming. Hence, polyherbal nanocolloids (PHNc) was formulated by using the extracts of Syzygium aromaticum, Cinnamomum verum, Emblica officinalis, Terminalia belerica, Terminalia chebula, and Cymbopogon citratus and physicochemically characterized. From mastitis milk samples, microorganisms were isolated including Acinetobacter junii, Klebsiella pneumoniae, Pseudomonas stutzeri, and Acinetobacter baumannii and screened for antibiotic susceptibility. All the isolated strains were tested with PHNc and compared with antibiotics. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and biofilm assays were performed at different concentrations, and antibacterial effects were quantified. In our results, PHNc showed potent bacteriostatic, bactericidal, and antibiofilm activity against all the strains. Our results indicated that PHNc can reduce the virulence factors responsible for infection by different bacterial strains. This study confirmed that PHNc had the potential to inhibit the growth of pathogenic Gram-negative and Gram-positive strains and could be utilized as an alternative to antibiotics to inhibit multidrug-resistant microbial pathogens in cattle.
Topics: Animals; Anti-Infective Agents; Bacteria; Cattle; Drug Resistance, Multiple, Bacterial; Female; Mastitis, Bovine; Plant Extracts
PubMed: 34762270
DOI: 10.1007/s12010-021-03748-w -
Environmental Technology Jun 2018The potential use of parboiled rice mill effluent as a cheap substrate for the production of homopolymer and copolymer of Polyhydroxyalkanoates (PHAs) by Acinetobacter...
The potential use of parboiled rice mill effluent as a cheap substrate for the production of homopolymer and copolymer of Polyhydroxyalkanoates (PHAs) by Acinetobacter junii BP 25 was investigated for the first time. Process optimization by one factor at a time led to homopolymer polyhydroxybutyrate (PHB) production of 2.64 ± 0.18 g/l with 94.28% PHB content using a two-stage batch cultivation mode. BP 25 furthermore produced polyhydroxybutyrate-co-hydroxyvalerate (P3 (HB-co-HV)), with the addition of valeric acid as an additive to the substrate, yielding (2.56 ± 0.12 g/l dry biomass, 2.20 ± 0.15 g/l PHA) a copolymer content of 85.93%. Thus, rice mill effluent can be an effective and relatively low-cost alternative for the production of PHA, replacing the pure substrates.
Topics: Acinetobacter; Biomass; Bioreactors; Oryza; Polyesters; Polyhydroxyalkanoates
PubMed: 28511586
DOI: 10.1080/09593330.2017.1330902 -
Environmental Science and Pollution... Apr 2017A lead-resistant bacterial strain was isolated from coal mine dump and identified as Acinetobacter junii Pb1 on basis of 16S rRNA (ribosomal ribonucleic acid) gene...
A new insight to adsorption and accumulation of high lead concentration by exopolymer and whole cells of lead-resistant bacterium Acinetobacter junii L. Pb1 isolated from coal mine dump.
A lead-resistant bacterial strain was isolated from coal mine dump and identified as Acinetobacter junii Pb1 on basis of 16S rRNA (ribosomal ribonucleic acid) gene sequencing. The minimum inhibitory concentration of lead for the strain was 16,000 mg l and it showed antibiotic and multi metal resistance. In aqueous culture, at an initial lead (Pb(II)) concentration of 100 and 500 mg l, lead adsorption and accumulation by the isolate was 100 and 60%, at pH 7 at 30 °C after 48 and 120 h, respectively. The two fractions of exopolysaccharide (EPS), loosely associated EPS (laEPS) and bound EPS (bEPS), and whole cells (devoid of EPS) showed high binding affinity towards Pb(II). The binding affinity of laEPS towards Pb(II) (1071 mg Pb g) was three times higher than that of bEPS (321.5 mg Pb g) and 6.5 times higher than that of whole cells (165 mg Pb g). The binding affinity of EPS and whole cells with Pb(II), reported in the current study, is considerably higher as compared to that reported in the literature, till date. SEM analysis, showed an increase in thickness of cells on exposure to Pb(II) and TEM analysis, revealed its accumulation (interior of cell) and its adsorption (with the external cell surface). The isolate was also found to be positive for indole acetic acid (IAA) and 1-aminocyclopropane-1-carboxylate (ACC) deaminase production which helps in promoting plant growth. Thus, this study provides a new understanding towards Pb(II) uptake by A. junii Pb1, highlighting its potential on the restoration of Pb(II) contaminated repositories.
Topics: Acinetobacter; Adsorption; Coal; Deoxyuracil Nucleotides; Lead; RNA, Ribosomal, 16S
PubMed: 28283975
DOI: 10.1007/s11356-017-8752-8