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1.
Ecotoxicol Environ Saf ; 208: 111621, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396141

RESUMO

The study explored the polycyclic aromatic hydrocarbon tolerance of indigenous biosurfactant producing microorganisms. Three bacterial species were isolated from crude oil contaminated sites of Haldia, West Bengal. The three species were screened for biosurfactant production and identified by 16S rRNA sequencing as Brevundimonas sp. IITISM 11, Pseudomonas sp. IITISM 19 and Pseudomonas sp. IITISM 24. The strains showed emulsification activities of 51%, 57% and 63%, respectively. The purified biosurfactants were characterised using FT-IR, GC-MS and NMR spectroscopy and found to have structural similarities to glycolipopeptides, cyclic lipopeptides and glycolipids. The biosurfactants produced were found to be stable under a wide range of temperature (0-100 °C), pH (4-12) and salinity (up to 20% NaCl). Moreover, the strains displayed tolerance to high concentrations (275 mg/L) of anthracene and fluorene and showed a good amount of cell surface hydrophobicity with different hydrocarbons. The study reports the production and characterisation of biosurfactant by Brevundimonas sp. for the first time. Additionally, the kinetic parameters of the bacterial strains grown on up to 300 mg/L concentration of anthracene and fluorene, ranged between 0.0131 and 0.0156 µmax (h-1), while the Ks(mg/L) ranged between 59.28 and 102.66 for Monod's Model. For Haldane-Andrew's model, µmax (h-1) varied between 0.0168 and 0.0198. The inhibition constant was highest for Pseudomonas sp. IITISM 19 on anthracene and Brevundimonas sp. IITISM 11 on fluorene. The findings of the study suggest that indigenous biosurfactant producing strains have tolerance to high PAH concentrations and can be exploited for bioremediation purposes.


Assuntos
Antracenos/metabolismo , Biodegradação Ambiental , Fluorenos/metabolismo , Tensoativos/metabolismo , Antracenos/química , Bactérias/metabolismo , Fluorenos/química , Glicolipídeos , Hidrocarbonetos/metabolismo , Cinética , Petróleo/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Pseudomonas/metabolismo , RNA Ribossômico 16S/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier , Tensoativos/química
2.
Ecotoxicol Environ Saf ; 208: 111673, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396005

RESUMO

In the present research, a bioremediation process was developed using solid complex bacterial agents (SCBA) through a combined two-step biodegradation process. Four isolated strains showed high efficiency for the degradation of total petroleum hydrocarbons (TPH) and the reduction of COD of the oily sludge, at 96.6% and 92.6%, respectively. The mixed strains together with bran prepared in form of SCBA exhibited improved performance compared to individual strains, all of which had an optimal temperature of around 35 °C. The use of SCBA provided advantages over commonly used liquid media for storage and transportation. The two-step process, consisting of firstly biosurfactant-assisted oil recovery and secondly biodegradation of the remaining TPH with SCBA, demonstrated the capability for treating oily sludge with high TPH content (>10 wt%) and short process period (60 days). The large-scale (5 tons oily sludge) field test, achieving a TPH removal efficiency of 93.8% and COD reduction of 91.5%, respectively, confirmed the feasibility and superiority of the technology for industrial applications.


Assuntos
Microbiota , Poluição por Petróleo/prevenção & controle , Petróleo/análise , Esgotos , Biodegradação Ambiental , Meios de Cultura , Hidrocarbonetos/análise , Hidrocarbonetos/metabolismo , Petróleo/metabolismo , Poluição por Petróleo/análise , Esgotos/química , Esgotos/microbiologia , Temperatura
3.
Ecotoxicol Environ Saf ; 207: 111514, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33254394

RESUMO

The present study investigated the stability and efficacy of a biosurfactant produced by Klebsiella sp. KOD36 under extreme conditions and its potential for enhancing the solubilization and degradation of phenanthrene in various environmental matrices. Klebsiella sp. KOD36 produced a mono-rhamnolipids biosurfactant with a low critical micelle concentration (CMC) value. The biosurfactant was stable under extreme conditions (60 °C, pH 10 and 10% salinity) and could lower surface tension by 30% and maintained an emulsification index of > 40%. The emulsion index was also higher (17-43%) in the presence of petroleum hydrocarbons compared to synthetic surfactant Triton X-100. Investigation on phenanthrene degradation in three different environmental matrices (aqueous, soil-slurry and soil) confirmed that the biosurfactant enhanced the solubilization and biodegradation of phenanthrene in all matrices. The high functional stability and performance of the biosurfactant under extreme conditions on phenanthrene degradation show the great potential of the biosurfactant for remediation applications under harsh environmental conditions.


Assuntos
Biodegradação Ambiental , Klebsiella/fisiologia , Fenantrenos/metabolismo , Tensoativos/metabolismo , Meios de Cultura , Emulsões , Glicolipídeos , Hidrocarbonetos/metabolismo , Klebsiella/metabolismo , Micelas , Petróleo/metabolismo , Solo , Poluentes do Solo/metabolismo
4.
Ecotoxicol Environ Saf ; 209: 111789, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33340957

RESUMO

Yeasts are the most predominant petroleum hydrocarbon-degrading fungi isolated from petroleum-contaminated soil. However, information of the transmembrane transport of petroleum hydrocarbon into yeast cells is limited. The present study was designed to explore the transmembrane transport mechanisms of the typical petroleum hydrocarbon n-hexadecane in Candida tropicalis cells with petroleum hydrocarbon biodegradation potential. Yeast cells were treated with n-hexadecane in different scenarios, and the percentage of intracellular n-hexadecane and transport dynamics were investigated accordingly. The intracellular concentration of n-hexadecane increased within 15 min, and transportation was inhibited by NaN3, an ATPase inhibitor. The uptake kinetics of n-hexadecane were well fitted by the Michaelis-Menten model, and Kt values ranged from 152.49 to 194.93 mg/L. All these findings indicated that n-hexadecane might cross the yeast cells in an energy-dependent manner and exhibit an affinity with the cell transport system. Moreover, the differentially expressed membrane proteins induced by n-hexadecane were identified and quantified by tandem mass tag labeling coupled with liquid chromatography tandem mass spectrometry analysis. The proteome analysis results demonstrated that energy production and conversion accounted for a large proportion of the functional classifications of the differentially expressed proteins, providing further evidence that sufficient energy supply is essential for transmembrane transport. Protein functional analysis also suggested that differentially expressed proteins associated with transmembrane transport processes are clearly enriched in endocytosis and phagosome pathways (p < 0.05), and the analysis supported the notion that the underlying transmembrane transport mechanism might be associated with endocytosis and phagosome pathways, revealing a new mechanism of n-hexadecane internalization by Candida tropicalis.


Assuntos
Alcanos/metabolismo , Biodegradação Ambiental , Candida tropicalis/metabolismo , Hidrocarbonetos/metabolismo , Cinética , Redes e Vias Metabólicas , Petróleo/análise , Proteoma/metabolismo , Proteômica , Leveduras/metabolismo
5.
Arch Microbiol ; 202(10): 2849-2853, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32683476

RESUMO

Achromobacter xylosoxidans DN002 is capable of utilizing numerous aromatic hydrocarbons as sole carbon and energy resource. In this study, the whole genome of strain DN002 was sequenced and analyzed, which consisted of one circular chromosome of 5,943,204 bp and a 278,917 bp plasmid with an average GC content of 65.46 mol%, 5694 protein-coding genes, 13 rRNA genes and 57 tRNA genes. Analysis of cluster of orthologous group (COG) demonstrated that strain DN002 had remarkable gene abundance foramino acid transport and metabolism, transcription, inorganic ion transport and metabolism, energy production and conversion, and carbohydrate transport and metabolism. Genes related to biodegradation of aromatic hydrocarbons, chemotaxis and flagella were identified from the genome, which will advance our fundamental understanding the molecular mechanism for degradation and metabolizing of aromatic hydrocarbons.


Assuntos
Achromobacter denitrificans/genética , Achromobacter denitrificans/metabolismo , Genoma Bacteriano/genética , Hidrocarbonetos Aromáticos/metabolismo , Composição de Bases/genética , Sequência de Bases/genética , Biodegradação Ambiental , Metabolismo Energético/genética , Metabolismo Energético/fisiologia , Hidrocarbonetos/metabolismo , Plasmídeos/genética
6.
Arch Microbiol ; 202(8): 2189-2196, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32524179

RESUMO

Three hydrocarbon degrading microorganisms were isolated from the soil samples collected from the storage sites of low viscosity spindle oil containers and identified on the basis of morphological and biochemical characteristics as Aeromonas hydrophila, Bacillus subtilis and Staphylococcus aureus. The study has revealed high ability of these microorganisms for oil biodegradation. The results have indicated that all isolates had the potential to breakdown the hydrocarbon. The most efficient bacteria among these examined was Aeromonas hydrophila which biodegraded almost all tested hydrocarbon giving a treatment percentage of 98% within 30 days which was considered as the perfect period for degradation. Also, a small scale was designed to treat the spindle oil with the using of oxidation process and all the tested organic materials were biodegraded in a treatment percentage of 100% within retention time of 20 days.


Assuntos
Bactérias/metabolismo , Biodegradação Ambiental , Petróleo/microbiologia , Microbiologia do Solo , Poluentes do Solo/metabolismo , Aeromonas hydrophila/metabolismo , Bacillus subtilis/metabolismo , Bactérias/isolamento & purificação , Hidrocarbonetos/metabolismo , Petróleo/metabolismo , Poluição por Petróleo , Staphylococcus aureus/metabolismo , Viscosidade
7.
Proc Biol Sci ; 287(1928): 20201029, 2020 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-32517627

RESUMO

In social insects, cuticular hydrocarbons function in nest-mate recognition and also provide a waxy barrier against desiccation, but basic evolutionary features, including the heritability of hydrocarbon profiles and how they are shaped by natural selection are largely unknown. We used a new pharaoh ant (Monomorium pharaonis) laboratory mapping population to estimate the heritability of individual cuticular hydrocarbons, genetic correlations between hydrocarbons, and fitness consequences of phenotypic variation in the hydrocarbons. Individual hydrocarbons had low to moderate estimated heritability, indicating that some compounds provide more information about genetic relatedness and can also better respond to natural selection. Strong genetic correlations between compounds are likely to constrain independent evolutionary trajectories, which is expected, given that many hydrocarbons share biosynthetic pathways. Variation in cuticular hydrocarbons was associated with variation in colony productivity, with some hydrocarbons experiencing strong directional selection. Altogether, this study builds on our knowledge of the genetic architecture of the social insect hydrocarbon profile and indicates that hydrocarbon variation is shaped by natural selection.


Assuntos
Formigas/fisiologia , Hidrocarbonetos/metabolismo , Seleção Genética , Animais , Formigas/genética , Característica Quantitativa Herdável
8.
Gene ; 755: 144909, 2020 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-32569720

RESUMO

In the microbial world, bacteria are the most effective agents in petroleum hydrocarbons (PHs) degradation, utilization/mineralization and they serve as essential degraders of crude oil contaminated environment. Some genes and traits are involved in the hydrocarbon utilization process for which transcriptome analyses are important to identify differentially expressed genes (DEGs) among different conditions, leading to a new understanding of genes or pathways associated with crude oil degradation. In this work, three crude oil utilizing Pseudomonas aeruginosa strains designated as N002, TP16 and J001 subjected to transcriptome analyses revealed a total of 81, 269 and 137 significant DEGs. Among them are 80 up-regulated genes and one downregulated gene of N002, 121 up- regulated and 148 down-regulated genes of TP16, 97 up-regulated and 40 down-regulated genes of J001 which are involved in various metabolic pathways. TP16 strain has shown more number of DEGs upon crude oil treatment in comparison to the other two strains. Through quantitative real time polymerase chain reaction (qRT-PCR), the selected DEGs of each strain from transcriptome data were substantiated. The results have shown that the up- regulated and down-regulated genes observed by qRT-PCR were consistent with transcriptome data. Taken together, our transcriptome results have revealed that TP16 is a potential P. aeruginosa strain for functional analysis of identified potential DEGs involved in crude oil degradation.


Assuntos
Biodegradação Ambiental , Petróleo/microbiologia , Pseudomonas aeruginosa/genética , Bactérias/genética , Regulação para Baixo , Poluentes Ambientais/efeitos adversos , Perfilação da Expressão Gênica/métodos , Regulação Bacteriana da Expressão Gênica/genética , Hidrocarbonetos/metabolismo , Transcriptoma/genética , Regulação para Cima
9.
Proc Natl Acad Sci U S A ; 117(20): 11029-11037, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32354993

RESUMO

Marine cold seeps transmit fluids between the subseafloor and seafloor biospheres through upward migration of hydrocarbons that originate in deep sediment layers. It remains unclear how geofluids influence the composition of the seabed microbiome and if they transport deep subsurface life up to the surface. Here we analyzed 172 marine surficial sediments from the deep-water Eastern Gulf of Mexico to assess whether hydrocarbon fluid migration is a mechanism for upward microbial dispersal. While 132 of these sediments contained migrated liquid hydrocarbons, evidence of continuous advective transport of thermogenic alkane gases was observed in 11 sediments. Gas seeps harbored distinct microbial communities featuring bacteria and archaea that are well-known inhabitants of deep biosphere sediments. Specifically, 25 distinct sequence variants within the uncultivated bacterial phyla Atribacteria and Aminicenantes and the archaeal order Thermoprofundales occurred in significantly greater relative sequence abundance along with well-known seep-colonizing members of the bacterial genus Sulfurovum, in the gas-positive sediments. Metabolic predictions guided by metagenome-assembled genomes suggested these organisms are anaerobic heterotrophs capable of nonrespiratory breakdown of organic matter, likely enabling them to inhabit energy-limited deep subseafloor ecosystems. These results point to petroleum geofluids as a vector for the advection-assisted upward dispersal of deep biosphere microbes from subsurface to surface environments, shaping the microbiome of cold seep sediments and providing a general mechanism for the maintenance of microbial diversity in the deep sea.


Assuntos
Sedimentos Geológicos/microbiologia , Hidrocarbonetos/metabolismo , Microbiota/fisiologia , Água do Mar/microbiologia , Alcanos/metabolismo , Archaea/classificação , Archaea/metabolismo , Bactérias/classificação , Bactérias/metabolismo , Biodiversidade , Sedimentos Geológicos/química , Golfo do México , Metagenoma , Metagenômica , Petróleo/metabolismo , Filogenia , RNA Ribossômico 16S/genética , Água do Mar/química
10.
Chemosphere ; 254: 126836, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32361541

RESUMO

For oil spilled at sea, the main weathering processes are evaporation, emulsification, photo-oxidation, dispersion and biodegradation. Of these, only biodegradation may completely remove hydrocarbons from the environment in the long term, as the other processes only serve to transform and dilute the oil components. As petroleum development is moving north, the probability of Arctic oil spills increases. Hence, it is imperative to develop methods for comprehensive risk assessment of oil spills in cold and ice-covered waters. Accurate biodegradation rates are an essential part of this, as they are required to predict the long-term effects of marine oil spills. In this paper, we present experimentally determined biodegradation rates for the component groups which are used to represent oil in the OSCAR oil spill model. The experiments have been carried out at seawater temperatures of -2∘C, 0∘C, 5∘C, and 13∘C. We show that for the lighter and more soluble oil components, the changes in degradation rates between 0∘C and 13∘C are well captured by a constant Q10 scaling law. At lower temperatures, and for heavier and less soluble components, the rates are not well described by a constant Q10, probably indicating that oil properties become important for the biodegradation rate.


Assuntos
Biodegradação Ambiental , Modelos Químicos , Petróleo , Poluentes Químicos da Água/química , Regiões Árticas , Temperatura Baixa , Hidrocarbonetos/metabolismo , Camada de Gelo , Poluição por Petróleo , Água do Mar , Temperatura , Poluentes Químicos da Água/análise
11.
Chemosphere ; 252: 126622, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32443279

RESUMO

This study aims at exploring the mechanism of fast-stimulating bioremediation of macro crude oil using matching Fenton pre-oxidation. The 80-day biodegradation experiment for soil S1 and S2, containing macro crude oil: C19-C29 and C17-C29 respectively, was conducted after Fenton pre-oxidation with three concentrations of H2O2 (225 mM, 450 mM, and 900 mM). Experimental results indicated that the bioremediation efficiency of macro crude oil was up to 57.1% (8853 mg/kg, S1) and 64.4% (11,719 mg/kg, S2) for 80-day fast-stimulating bioremediation using matching Fenton pre-oxidation (450 mM H2O2), which was 1.8-2.6 times that (S1: 22.2-37.1%; S2: 36.1-39.6%) for slow-stimulating bioremediation using un-matching Fenton pre-oxidation. Furthermore, the high-throughput analysis revealed that genera Sedimentibacter, Caenispirillum, and Brevundimonas became the dominant bacteria after matching Fenton pre-oxidation. Meanwhile, the highest logarithmic growth rate of indigenous hydrocarbon degraders (IHD) was obtained (S1: 64% and S2: 60%) for fast-stimulating bioremediation. And the consumption of NH4+-N was up to 90% and 94% in S1 and S2 within 60 days for fast-stimulating bioremediation, approximately 1.4 and 2.2 times that (S1: 65% and 62%; S2: 47% and 41%) for slow-stimulating remediation. The results showed that the macro crude oil became the main carbon source for IHD for the fast-stimulating bioremediation, resulting in the rapid growth of IHD. Thus, this study provides a fast and efficient remediation technology for bioremediation of macro crude oil-contaminated soils.


Assuntos
Biodegradação Ambiental , Poluentes do Solo/análise , Bactérias/metabolismo , Hidrocarbonetos/metabolismo , Peróxido de Hidrogênio/metabolismo , Oxirredução , Petróleo/análise , Solo , Microbiologia do Solo
12.
Sci Rep ; 10(1): 8519, 2020 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-32444666

RESUMO

A novel Bacillus licheniformis strain (DM-1) was isolated from a mature reservoir in Dagang oilfield of China. DM-1 showed unique properties to utilize petroleum hydrocarbons and agroindustrial by-product (molasses) for exopolysaccharide (EPS) production under oil recovery conditions. The DM-1 EPS was proven to be a proteoglycan with a molecular weight of 568 kDa. The EPS showed shear thinning properties and had high viscosities at dilute concentrations (<1%, w/v), high salinities, and elevated temperatures. Strain DM-1 could degrade long-chain n-alkanes up to C36. Viscosity reduction test have shown that the viscosity of the crude oil was reduced by 40% compared with that before DM-1 treatment. Sand pack flooding test results under simulated reservoir conditions have shown that the enhanced oil recovery efficiency was 19.2% after 7 days of in-situ bioaugmentation with B. licheniformis DM-1. The obtained results indicate that strain DM-1 is a promising candidate for in situ microbial enhanced oil recovery (MEOR).


Assuntos
Alcanos/metabolismo , Bacillus licheniformis/metabolismo , Biodegradação Ambiental , Hidrocarbonetos/metabolismo , Campos de Petróleo e Gás/microbiologia , Petróleo/metabolismo , Polissacarídeos Bacterianos/metabolismo , Bacillus licheniformis/isolamento & purificação
13.
Chemosphere ; 253: 126678, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32278192

RESUMO

Hypoxia and petrogenic hydrocarbon contamination are two anthropogenic stressors that coexist in coastal environments. Although studies have estimated the impact of each stressor separately, few investigations have assessed the effects of these stressors in interaction. We therefore investigated the impact of these combined stressors on sea bass, (Dicentrarchus labrax) physiology. After experimental contamination with physically dispersed oil, fish were exposed to hypoxia or normoxia, and active/standard metabolic rates (AMR and SMR, respectively), and metabolic scope (MS) were estimated. At the protocol's end, the uptake of polycyclic aromatic hydrocarbons (PAHs) was estimated by evaluating relative concentrations of bile metabolites. In terms of bile metabolites, our results validated the uptake of PAHs by contaminated fish in our experimental settings, and further suggest that the hypoxic period after contamination does not reduce or increase compound metabolization processes. Our data showed significant effects of hypoxia on all metabolic rates: a significant drastic AMR reduction and significant SMR diminution led to decreased MS. We also found that oil contamination significantly impacted AMR and MS, but not SMR. These results suggested that when evaluated separately, hypoxia or oil affect the metabolic rate of sea bass. On the other hand, when evaluated in combination, no cumulative effects were observed, since fish exposed to both stressors did not show a stronger impact on metabolism than fish exposed to hypoxia alone. This suggests that oil impacts fish metabolism when fish occupy normoxic waters, and that oil does not magnify hypoxia-induced effects on fish metabolism.


Assuntos
Bass/fisiologia , Poluição por Petróleo , Aerobiose/efeitos dos fármacos , Animais , Bass/metabolismo , Bile/metabolismo , Hidrocarbonetos/metabolismo , Hipóxia/metabolismo , Hipóxia/veterinária , Hidrocarbonetos Policíclicos Aromáticos/metabolismo
14.
Ecotoxicol Environ Saf ; 195: 110481, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32203775

RESUMO

Archaea remain important players in global biogeochemical cycles worldwide, including in the highly productive mangrove estuarine ecosystems. In the present study, we have explored the diversity, distribution, and function of the metabolically active fraction of the resident archaeal community of the Sundarban mangrove ecosystem, using both culture-independent and culture-dependent approaches. To evaluate the diversity and distribution pattern of the active archaeal communities, RNA based analysis of the 16S rRNA gene was performed on an Illumina platform. The active Crenarchaeal community was observed to remain constant while active Euryarchaeal community underwent considerable change across the sampling sites depending on varying anthropogenic factors. Haloarchaea were the predominant group in hydrocarbon polluted sediments, leading us to successfully isolate eleven p-hydroxybenzoic acid degrading haloarchaeal species. The isolates could also survive in benzoic acid, naphthalene, and o-phthalate. Quantitative estimation of p-hydroxybenzoic acid degradation was studied on select isolates, and their ability to reduce COD of polluted saline waters of Sundarban was also evaluated. To our knowledge, this is the first ever study combining culture-independent (Next Generation sequencing and metatranscriptome) and culture-dependent analyses for an assessment of archaeal function in the sediment of Sundarban.


Assuntos
Archaea/metabolismo , Sedimentos Geológicos/microbiologia , Hidrocarbonetos/metabolismo , Poluentes Químicos da Água/metabolismo , Archaea/genética , Archaea/isolamento & purificação , Biodegradação Ambiental , Crenarchaeota/isolamento & purificação , Euryarchaeota/isolamento & purificação , Parabenos/metabolismo , RNA Ribossômico 16S/genética , Áreas Alagadas
15.
J Biotechnol ; 313: 1-10, 2020 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-32151643

RESUMO

The endophyte Burkholderia sp. WYAT7 isolated from the medicinal plant Artemisia nilagirica (Clarke) Pamp. was analyzed for its ability to produce biosurfactant. The evaluation of biosurfactant production was conducted using different screening methods which confirmed the presence of biosurfactant in the culture supernatant. CTAB- methylene blue agar plate method was used for the screening of glycolipid biosurfactant production. The biosurfactant produced by the bacteria effectively metabolized hydrocarbons present in the bacterial culture media. Fourier transform infrared spectroscopic (FTIR) analysis of biosurfactant provided the details regarding OH stretching, stretching vibrations of acyl chain, CO stretching, stretching vibrations of ether and vibrations of glycosidic linkages in the biosurfactant. The stretching vibrations of glycosidic linkage in the fingerprint regions of FTIR spectrum (1200 cm-1 to 800 cm-1 regions) confirms that the biosurfactant produced was a glycolipid. The GC-MS analysis confirmed the methyl and ethyl esters of fatty acids. The biosurfactant from the bacteria exhibited antibacterial activity against bacterial pathogens such as Pseudomonas aeruginosa (MTCC 2453), Escherichia coli (MTCC 1610), Salmonella paratyphi and Bacillus subtilis. The glycolipid biosurfactant had antibiofilm activity as evidenced in Staphylococcus aureus (MTCC 1430). All these results indicated the beneficial effect of the biosurfactant in plant-endophyte interactions. The properties exhibited by the biosurfactant suggest that it can be exploited commercially for the production of novel antibiotics.


Assuntos
Antibacterianos/química , Artemisia/microbiologia , Biofilmes/efeitos dos fármacos , Burkholderia/química , Glicolipídeos/química , Tensoativos/química , Antibacterianos/farmacologia , Bacillus subtilis/efeitos dos fármacos , Endófitos , Escherichia coli/efeitos dos fármacos , Glicolipídeos/farmacologia , Hidrocarbonetos/metabolismo , Pseudomonas aeruginosa/efeitos dos fármacos , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Tensoativos/farmacologia
16.
Sci Rep ; 10(1): 4305, 2020 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-32152410

RESUMO

Competing time scales involved in rapid rising micro-droplets in comparison to substantially slower biodegradation processes at oil-water interfaces highlights a perplexing question: how do biotic processes occur and alter the fates of oil micro-droplets (<500 µm) in the 400 m thick Deepwater Horizon deep-sea plume? For instance, a 200 µm droplet traverses the plume in ~48 h, while known biodegradation processes require weeks to complete. Using a microfluidic platform allowing microcosm observations of a droplet passing through a bacterial suspension at ecologically relevant length and time scales, we discover that within minutes bacteria attach onto an oil droplet and extrude polymeric streamers that rapidly bundle into an elongated aggregate, drastically increasing drag that consequently slows droplet rising velocity. Results provide a key mechanism bridging competing scales and establish a potential pathway to biodegradation and sedimentations as well as substantially alter physical transport of droplets during a deep-sea oil spill with dispersant.


Assuntos
Bactérias/isolamento & purificação , Biodegradação Ambiental , Hidrocarbonetos/metabolismo , Poluição por Petróleo/análise , Água do Mar/microbiologia , Poluentes Químicos da Água/análise , Bactérias/metabolismo , Água do Mar/química
17.
Artigo em Inglês | MEDLINE | ID: mdl-32131529

RESUMO

Due to the increasing pollution by petroleum hydrocarbons (PHs), it is an important task to develop eco-friendly and highly efficient methods for remediating petroleum-contaminated soils. In this study, bioremediation technology was applied to remediate PHs contaminated soils, and the bacterial community structure and physicochemical characteristics of the soil treated using different bioremediation regimens were analyzed. Compared with the control condition (S0), the PHs removal efficiency of biostimulation (S2) and bioaugmentation (S3) was increased significantly. Combined biostimulation with bioaugmentation (S4) had the highest PHs removal efficiency, up to 60.14 ± 4.12%. Among all the selected remediation strategies (S1-S4, S1: soil moisture content: 25-30%), the bacterial alpha-diversity was higher than in S0. The genera Acinetobacter, Escherichia-Shigella, Bacteroides, Microbacterium, and Parabacteroides were found to greatly contribute to PHs' degradation. In the group S4, the PH-degraders and soil enzyme activity were higher than in the other remediation regimens, and these indices gradually decreased in the mid-to-later periods of all remediation tests. Additionally, the abundance of alkB and nah genes was increased by improving the environmental condition of the microorganism communities. Redundancy analysis (RDA) revealed that the total nitrogen (TN) and total phosphorus (TP) had a positive correlation with total PHs degradation. This study offers insights into the microbial community response to environmental factors during bioremediation, which shows a promoting effect in enhancing the efficiency of PHs remediation.


Assuntos
Biodegradação Ambiental , Recuperação e Remediação Ambiental , Petróleo , Microbiologia do Solo , Poluentes do Solo , Bactérias/metabolismo , Recuperação e Remediação Ambiental/métodos , Hidrocarbonetos/metabolismo , Petróleo/metabolismo , Solo/química
18.
Chemosphere ; 248: 126023, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32007777

RESUMO

Biodegradation by microorganisms is a useful tool that helps alleviating hydrocarbon pollution in nature. Microbes are more efficient in degradation under aerobic than anaerobic conditions, but the majority of sediment by volume is generally anoxic. Incubation experiments were conducted to study the biodegradation potential of naphthalene-a common polycyclic aromatic hydrocarbon (PAH)-and the diversity of microbial communities in presence/absence of activated carbon (AC) under aerobic/anaerobic conditions. Radio-respirometry experiments with endogenous microorganisms indicated that degradation of naphthalene was strongly stimulated (96%) by the AC addition under anaerobic conditions. In aerobic conditions, however, AC had no effects on naphthalene biodegradation. Bioaugmentation tests with cultured microbial populations grown on naphthalene showed that AC further stimulated (92%) naphthalene degradation in anoxia. Analysis of the 16S rRNA gene sequences implied that sediment amendment with AC increased microbial community diversity and changed community structure. Moreover, the relative abundance of Geobacter, Thiobacillus, Sulfuricurvum, and methanogenic archaea increased sharply after amendment with AC under anaerobic conditions. These results may be explained by the fact that AC particles promoted direct interspecies electron transfer (DIET) between microorganisms involved in PAH degradation pathways. We suggest that important ecosystem functions mediated by microbes-such as hydrocarbon degradation-can be induced and that AC enrichment strategies can be exploited for facilitating bioremediation of anoxic oil-contaminated sediments and soils.


Assuntos
Microbiota , Poluição por Petróleo , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Microbiologia da Água , Poluentes Químicos da Água/metabolismo , Anaerobiose , Archaea/metabolismo , Biodegradação Ambiental , Carvão Vegetal , Sedimentos Geológicos/química , Hidrocarbonetos/metabolismo , Naftalenos , RNA Ribossômico 16S/genética , Solo
19.
BMC Evol Biol ; 20(1): 21, 2020 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-32019492

RESUMO

BACKGROUND: The hybridizing field crickets, Gryllus firmus and Gryllus pennsylvanicus have several barriers that prevent gene flow between species. The behavioral pre-zygotic mating barrier, where males court conspecifics more intensely than heterospecifics, is important because by acting earlier in the life cycle it has the potential to prevent a larger fraction of hybridization. The mechanism behind such male mate preference is unknown. Here we investigate if the female cuticular hydrocarbon (CHC) profile could be the signal behind male courtship. RESULTS: While males of the two species display nearly identical CHC profiles, females have different, albeit overlapping profiles and some females (between 15 and 45%) of both species display a male-like profile distinct from profiles of typical females. We classified CHC females profile into three categories: G. firmus-like (F; including mainly G. firmus females), G. pennsylvanicus-like (P; including mainly G. pennsylvanicus females), and male-like (ML; including females of both species). Gryllus firmus males courted ML and F females more often and faster than they courted P females (p < 0.05). Gryllus pennsylvanicus males were slower to court than G. firmus males, but courted ML females more often (p < 0.05) than their own conspecific P females (no difference between P and F). Both males courted heterospecific ML females more often than other heterospecific females (p < 0.05, significant only for G. firmus males). CONCLUSIONS: Our results suggest that male mate preference is at least partially informed by female CHC profile and that ML females elicit high courtship behavior in both species. Since ML females exist in both species and are preferred over other heterospecific females, it is likely that this female type is responsible for most hybrid offspring production.


Assuntos
Escamas de Animais/química , Corte , Gryllidae/fisiologia , Hibridização Genética/fisiologia , Hidrocarbonetos/análise , Comportamento Sexual Animal/fisiologia , Escamas de Animais/metabolismo , Animais , Feminino , Gryllidae/genética , Hidrocarbonetos/metabolismo , Masculino , Reprodução/fisiologia
20.
Ecotoxicol Environ Saf ; 192: 110250, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32028154

RESUMO

A bacterial strain designated Lysinibacillus fusiformis 15-4 was isolated from oil-free soil on the Qinghai-Tibet Plateau, which can grow well utilizing petroleum hydrocarbons as a carbon source at a lower temperature. To deeply characterize the molecular adaptations and metabolic processes of this strain when grown in a petroleum-containing environment, transcriptome analysis was performed. A total of 4664 genes and the expression of 3969 genes were observed in strain 15-4. When the strain was grown in petroleum-containing medium, 2192 genes were significantly regulated, of which 1312 (60%) were upregulated and 880 (40%) were downregulated. This strain degraded and adapted to petroleum via modulation of diverse molecular processes, including improvements in transporter activity, oxidoreductase/dehydrogenase activity, two-component system/signal transduction, transcriptional regulation, fatty acid catabolism, amino acid metabolism, and environmental stress responses. Many strain-specific genes were involved in the oxidation of hydrocarbon compounds, such as several luciferase family alkane monooxygenase genes, flavin-utilizing monooxygenase family genes, and flavoprotein-like family alkanesulfonate monooxygenase genes. Several cold shock protein genes were also induced suggesting adaptation to cold environments and the potential for petroleum degradation at low temperatures. The results obtained in this study may broaden our understanding of molecular adaptation of bacteria to hydrocarbon-containing environments and may provide valuable data for further study of L. fusiformis.


Assuntos
Bacillaceae/genética , Bacillaceae/metabolismo , Petróleo/metabolismo , Transportadores de Cassetes de Ligação de ATP/metabolismo , Adaptação Fisiológica , Bacillaceae/isolamento & purificação , Biodegradação Ambiental , Proteínas e Peptídeos de Choque Frio/biossíntese , Proteínas e Peptídeos de Choque Frio/genética , Temperatura Baixa , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Hidrocarbonetos/metabolismo , Oxigenases de Função Mista/biossíntese , Oxigenases de Função Mista/genética , Microbiologia do Solo , Tibet
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