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1.
Mar Genomics ; 60: 100875, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34627547

RESUMO

Alcanivorax belongs to the hydrocarbonoclastic group of bacteria that are known for their preferential growth on alkanes and other related compounds. Here we report the genomic features of Alcanivorax marinus strain NMRL4 (=MCC 4632) isolated from oil polluted seawater of the Arabian Sea. Its 4,062,055 bp genome with 66.1% GC content encodes for 3935 coding sequences. The genome annotations of strain NMRL4 revealed the presence of multiple hydrocarbon degradation genes suggestive of its wider hydrocarbon substrate range. The strain encodes for three alkane monooxygenases, two cytochrome P450 and two flavin binding monooxygenases for degradation of short and long-chain alkanes. The genome shows capabilities for scavenging of nutrients, biofilm formation at oil-water interfaces, chemotaxis, motility and habitat specific adaptation. The genomic insights showed that the strain NMRL4 is an ideal candidate for bioremediation of pollutant petroleum hydrocarbons from the marine environment.


Assuntos
Alcanivoraceae , Petróleo , Alcanivoraceae/genética , Bactérias , Biodegradação Ambiental , Hidrocarbonetos , Água do Mar
2.
Microb Pathog ; 160: 105167, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34478859

RESUMO

Poly-hydroxybutyrate-co-hydroxyhexanoate (PHBH) is a biodegradable, water-insoluble polymer produced by specific bacteria. The monomers of PHBH are the hydroxyalkanoic acids 3-hydroxybutyrate (3HB) and 3-hydroxyhexanoate (3HH). Previously, we reported that 3HB and 3HH showed marked antibacterial activities against the shrimp pathogenic bacterium Vibrio penaeicida, and that addition of 5% (w/w) PHBH to the standard aquaculture diet significantly increased survival rate in kuruma shrimp (Marsupenaeus japonicus) after challenge by V. penaeicida, which we attributed to the degradation of PHBH to its monomers in the shrimp gut. In the present study, we isolated four strains of bacteria with high PHBH-degrading activity and evaluated their inhibitory effects on V. penaeicida with PHBH: one strain from shrimp gut contents (E1; Pseudoalteromonas shioyasakiensis/P. mariniglutinosa), two strains from coastal surface seawater (F1; P. shioyasakiensis/P. mariniglutinosa, and F5; Alcanivorax dieselolei/A. xenomutans), and one strain that was a contaminant in commercial PHBH powder (Y1; Bacillus pseudofirmus). Strains E1, F1, and Y1 showed strong PHBH-degrading activity within 24 h of inoculation to PHBH-containing agar plates. Although none of the isolates alone had any effect on the growth of V. penaeicida, when cultured with E1 or F1 and PHBH, the growth of V. penaeicida was markedly suppressed. Incubation with E1 and PHBH resulted in a gradual reduction in the concentration of V. penaeicida from 2 days after the start of incubation until the concentration was 1.2% of that in the control (V. penaeicida alone). Incubation with F1 and PHBH resulted in a rapid reduction in the concentration of V. penaeicida from 2 days after the start of incubation until the concentration was only 0.32% of that of the control. Compared with strains E1 and F1, Y1 showed similar PHBH-degrading activity but did not show any suppressive effect on the growth of V. penaeicida until 5 days after the start of incubation. In addition, this suppressive effect was relatively weak compared with that of the other two strains, suggesting that Y1 can quickly degrade PHBH but that it takes several days to produce monomers. Together, these results suggest that addition to the aquaculture diet of PHBH and PHBH-degrading bacteria that rapidly degrade PHBH to its monomers may speed up degradation of PHBH to its monomers in the shrimp gut, and that it would increase resistance to infection mortality by V. penaeicida in kuruma shrimp.


Assuntos
Penaeidae , Vibrio , Alcanivoraceae , Animais , Bacillus , Hidroxibutiratos , Pseudoalteromonas
3.
Environ Pollut ; 290: 117986, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34523511

RESUMO

Though many studies pertaining to soil bioremediation have been performed to study the microbial kinetics in shake flasks, the process efficiency in column tests is seldom. In the present study, soil columns tests were carried out to study the biodegradation of soil contaminated with a high concentration of diesel (≈19.5 g/kg) petroleum hydrocarbons expressed as C10-C50. Experiments were done with crude enzymatic cocktail produced by the hydrocarbonoclastic bacterium, Alcanivorax borkumensis. A. borkumensis was grown on a media with 3% (v/v) motor oil as the sole carbon and energy source. The effects of the enzyme concentration, treatment time and oxidant on the bioremediation efficiency of C10-C50 were investigated. A batch test was also carried out in parallel to investigate the stability of the enzymes and the effect of the biosurfactants on the desorption and the bioconversion of C10-C50. Batch tests indicated that the biosurfactants significantly affected the desorption and alkane hydroxylase and lipase enzymes, maintained their catalytic activity during the 20-day test, with a half-life of 7.44 days and 8.84 days, respectively. The crude enzyme cocktail, with 40 U/mL of lipase and 10 U/mL of alkane hydroxylase, showed the highest conversion of 57.36% after 12 weeks of treatment with a degradation rate of 0.0218 day-1. The results show that the soil column tests can be used to optimize operating conditions for hydrocarbon degradation and to assess the performance of the overall bioremediation process.


Assuntos
Alcanivoraceae , Petróleo , Poluentes do Solo , Biodegradação Ambiental , Hidrocarbonetos , Solo , Microbiologia do Solo , Poluentes do Solo/análise
4.
J Hazard Mater ; 414: 125586, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-34030422

RESUMO

In Antarctic regions, the composition and metabolic activity of microbial assemblages associated with plastic debris ("plastisphere") are almost unknown. A macroplastic item from land (MaL, 30 cm) and a mesoplastic from the sea (MeS, 4 mm) were collected in Maxwell Bay (King George Island, South Shetland) and analyzed by Fourier transform infrared spectroscopy in attenuated total reflectance geometry (FTIR-ATR), which confirmed a polystyrene foam and a composite high-density polyethylene composition for MaL and MeS, respectively. The structure and function of the two plastic-associated prokaryotic communities were studied by complementary 16S ribosomal RNA gene clone libraries, total bacterioplankton and culturable heterotrophic bacterial counts, enzymatic activities of the whole community and enzymatic profiles of bacterial isolates. Results showed that Gamma- and Betaproteobacteria (31% and 28%, respectively) dominated in MeS, while Beta- and Alphaproteobacteria (21% and 13%, respectively) in MaL. Sequences related to oil degrading bacteria (Alcanivorax,Marinobacter) confirmed the known anthropogenic pressure in King George Island. This investigation on plastic-associated prokaryotic structure and function represents the first attempt to characterize the ecological role of plastisphere in this Antarctic region and provides the necessary background for future research on the significance of polymer type, surface characteristics and environmental conditions in shaping the plastisphere.


Assuntos
Alcanivoraceae , Plásticos , Regiões Antárticas , Bactérias/genética , Poliestirenos
5.
Curr Microbiol ; 78(3): 1053-1060, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33599831

RESUMO

Two novel Alcanivorax-related strains, designated ST75FaO-1T and 521-1, were isolated from the seawater of the South China Sea and the deep-sea sediment of the West Pacific Ocean, respectively. Both strains are Gram-stain-negative, rod-shaped, and non-motile, and grow at 10-40 °C, pH 5.0-10.0, in the presence of 1.0-15.0% (w/v) NaCl. Their 16S rRNA gene sequences showed 99.9% similarity. Phylogenetic analysis based on the 16S rRNA gene sequences indicated that both strains belong to the genus Alcanivorax, and share 92.9-98.1% sequence similarity with all valid type strains of this genus, with the highest similarity being to type strain Alcanivorax venustensis DSM 13974T (98.0-98.1%). Digital DNA-DNA hybridization (dDDH) and average nucleotide identity values between strains ST75FaO-1T and 521-1 were 75.7% and 97.1%, respectively, while the corresponding values with A. venustensis DSM 13974T were only 25.4-25.6% and 82.4-82.7%, respectively. The two strains contained similar major cellular fatty acids including C16:0, C18:1 ω7c/ω6c, C19:0 cyclo ω8c, C16:1 ω7c/ω6c, C12:0 3-OH, and C12:0. The genomic G + C content of strains ST75FaO-1T and 521-1 were 66.3% and 66.1%, respectively. Phosphatidylglycerol, phosphatidylethanolamine, two unidentified phospholipids, and one unidentified polar lipid were present in both strains. On the basis of phenotypic and genotypic characteristics, the two strains represent a novel species within the genus Alcanivorax, for which the name Alcanivorax profundimaris sp. nov. is proposed. The type strain is ST75FaO-1T (= MCCC 1A17714T = KCTC 82142T).


Assuntos
Alcanivoraceae , Alcanivoraceae/genética , Técnicas de Tipagem Bacteriana , China , DNA Bacteriano/genética , Ácidos Graxos , Oceano Pacífico , Fosfolipídeos , Filogenia , RNA Ribossômico 16S/genética , Água do Mar , Análise de Sequência de DNA
6.
J Hazard Mater ; 403: 123569, 2021 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-32798793

RESUMO

Identification of microorganisms that contribute to the whole microbial community is important. In this study, dynamic changes in bioaugmentation process in diesel-polluted seawater collected from two different sites were assessed via simulation experiments. Ultraviolet spectrophotometry and analysis using the molecular operating environment software revealed that the degradation rate of diesel due to bioaugmentation was higher than 70 % after 45 days because of the formation of hydrogen bonds among biosurfactants and diesel components. Community structure and functional genes were analysed via high-throughput sequencing. Results showed that community diversity recovered during bioaugmentation. Principal coordinate analysis showed that the difference in microbial community between the two sites was considerably smaller than that when diesel was added and bioaugmentation was conducted. After bioaugmentation, the main families playing key roles in degradation that became dominant were Alcanivoracaceae, Rhodobiaceae, and Rhodospirillaceae. Moreover, the abundance of functional genes remarkably increased at two different sites.


Assuntos
Alcanivoraceae , Microbiota , Biodegradação Ambiental , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Água do Mar
7.
Sci Total Environ ; 761: 143209, 2021 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-33160671

RESUMO

The environmental hazards of oil spills cannot be underestimated. Bioremediation holds promise among various approaches to tackle oil spills in soils and sediments. In particular, using oil-degrading bacteria is an efficient and self-regulating way to remove oil spills. Using animals for oil spills remediation is in its infancy, mostly due to the lack of efficient oil-degrading capabilities in eukaryotes. Here we show that Caenorhabditis elegans nematodes survive for extended periods (up to 22 days) on pure crude oil diet. Moreover, we report for the first time the use of Alcanivorax borkumensis hydrocarbonoclastic bacteria for colonisation of C. elegans intestines, which allows for effective digestion of crude oil by the nematodes. The worms fed and colonised by A. borkumensis demonstrated the similar or even better longevity, resistance against oxidative and thermal stress and reproductivity as those animals fed with Escherichia coli bacteria (normal food). Importantly, A. borkumensis-carrying nematodes were able to accumulate oil droplet from oil-contaminated soils. Artificial colonisation of soil invertebrates with oil-degrading bacteria will be an efficient way to distribute microorganisms in polluted soil, thus opening new avenues for oil spills zooremediation.


Assuntos
Alcanivoraceae , Poluição por Petróleo , Petróleo , Animais , Biodegradação Ambiental , Caenorhabditis elegans , Intestinos
8.
Arch Microbiol ; 204(1): 106, 2021 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-34972960

RESUMO

An alkaliphilic and aerobic bacterium, designated as strain JB21T, was isolated from a soda alkali-saline soil sample in Heilongjiang, Northeast China. Strain JB21T is a Gram-stain-negative, rod-shaped, non-motile and amylase-positive bacterium. Growth occurred at 15-45 °C (optimum, 35-37 °C), in the presence of 0-15.0% (w/v) NaCl (optimum, 1.0%) and at pH 6.5-10.5 (optimum, pH 8.5-9.5). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JB21T was most closely related to type strains of the genus Alcanivorax, with the highest sequence similarity to Alcanivorax indicus SW127T (96.3%), and shared 95.4-93.1% sequence identity with other valid type strains of this genus. The major cellular fatty acids identified were C16:0 and summed feature 8 (C18:1ω6c and/or C18:1ω7c). The polar lipids comprised phosphatidylethanolamine, phosphatidylglycerol and one unidentified phospholipid. The genomic G + C content of strain JB21T was 61.3 mol%. The digital DNA-DNA hybridization (dDDH) estimation and average nucleotide identity (ANI) between strain JB21T and type strains of the genus Alcanivorax were 18.3-23.2% and 69.2-79.0%, respectively. On the basis of its phenotypic and phylogenetic characteristics, we suggest the creation of a new species within the Alcanivorax genus, named Alcanivorax limicola sp. nov., type strain JB21T (= CGMCC 1.16632T = JCM 33717T).


Assuntos
Alcanivoraceae , Alcanivoraceae/genética , Álcalis , Técnicas de Tipagem Bacteriana , DNA Bacteriano/genética , Ácidos Graxos/análise , Fosfolipídeos/análise , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Solo , Microbiologia do Solo
9.
Int J Syst Evol Microbiol ; 70(9): 4960-4965, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32762800

RESUMO

A Gram-stain-negative, motile, aerobic and heterotrophic bacterium, designated as GYS_M3HT, was isolated from marine coastal sediment sampled at Xiamen Island. Cells were rod-shaped with one polar flagellum and weakly positive for oxidase and catalase. Growth of the strain occurred at pH 6-9 (optimum, pH 7-8), at 15-37 °C (optimum, 28 °C) and with NaCl concentrations of 1.0-6.0 % (optimum, 2.0 %). It had highest 16S rRNA similarity (97.7 %) to Ketobacter alkanivorans GI5T, followed by the members of the genus Alcanivorax (lower than 91.2 %). The results of phylogenetic analysis indicated that it belonged to the genus Ketobacter within the family Alcanivoracaceae. In addition, the average nucleotide identity and digital DNA-DNA hybridization values between strain GYS_M3HT and K. alkanivorans GI5T were 71.4 and 19.7 %, respectively, indicating that strain GYS_M3HT belonged to a novel species. Its genome consisted of 5 318 758 bp, with a genomic DNA G+C content of 50.0 mol%. The respiratory quinone was Q-8 and the dominant fatty acids were identified as iso-C15 : 0 (25.4 %), C16 : 1 ω6c/C16 : 1 ω7c (14.4 %) and iso-C13 : 0 (7.2 %). The main polar lipids were phosphatidylethanolamine and phosphatidylglycerol. Therefore, based on phenotypic, chemotaxonomic and phylogenetic results, strain GYS_M3HT represents a novel species within the genus Ketobacter, for which the name Ketobacter nezhaii sp. nov. is proposed, with the type strain GYS_M3HT (=MCCC 1A13808T=KCTC 72247T).


Assuntos
Alcanivoraceae/classificação , Sedimentos Geológicos/microbiologia , Filogenia , Alcanivoraceae/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Ilhas , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/química
10.
Int J Syst Evol Microbiol ; 70(7): 4280-4284, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32618558

RESUMO

A taxonomic study was carried out on strain PA15-N-34T, which was isolated from deep-sea sediment of Pacific Ocean. The bacterium was Gram-stain-positive, oxidase- and catalase-positive and rod-shaped. Growth was observed at salinity of 0-15.0% NaCl and at temperatures of 10-45 °C. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain PA15-N-34T belonged to the genus Alcanivorax, with the highest sequence similarity to Alcanivorax profundi MTEO17T (97.7 %), followed by Alcanivorax nanhaiticus 19 m-6T (97.3 %) and 12 other species of the genus Alcanivorax (93.4 %-97.0 %). The average nucleotide identity and DNA-DNA hybridization values between strain PA15-N-34T and type strains of the genus Alcanivorax were 71.46-81.78% and 18.7-25.2 %, respectively. The principal fatty acids (>10 %) were summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c; 31.2 %), C16 : 0 (25.0 %) and summed feature 3 (14.6 %). The DNA G+C content was 57.15 mol%. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, four unidentified aminolipids and three unidentified lipids. The novel strain can be differentiated from its closest type strain by a negative test for urease and the presence of diphosphatidylglycerol and aminolipid. The combined genotypic and phenotypic data show that strain PA15-N-34T represents a novel species within the genus Alcanivorax, for which the name Alcanivorax sediminis sp. nov. is proposed, with the type strain PA15-N-34T (=MCCC 1A14738T=KCTC 72163T).


Assuntos
Alcanivoraceae/classificação , Sedimentos Geológicos/microbiologia , Filogenia , Água do Mar/microbiologia , Alcanivoraceae/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Oceano Pacífico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Salinidade , Análise de Sequência de DNA , Temperatura
11.
Genomics ; 112(5): 3268-3273, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32553480

RESUMO

A new Alcanivorax sp. VBW004 was isolated from a shallow hydrothermal vent in Azores Island, Portugal. In this study, we determined VBW004 was resistant to copper. This strain showed maximum tolerance of copper concentrations up to 600 µg/mL. Based on 16S rRNA gene sequencing and phylogeny revealed that this strain was more closely related to Alcanivorax borkumensis SK2. We sequenced the genome of this strain that consist of 3.8 Mb size with a G + C content of 58.4 %. In addition, digital DNA-DNA hybridizations (dDDH) and the average nucleotide identities (ANI) analysis between Alcanivorax borkumensis SK2 and Alcanivorax jadensis T9 revealed that Alcanivorax sp. VBW004 belongs to new species. Functional annotation revealed that the genome acquired multiple copper resistance encoding genes that could assist VBW004 to respond to high Cu toxicity. Our results from biosorption analysis presumed that the VBW004 is an ecologically important bacterium that could be useful for copper bioremediation.


Assuntos
Alcanivoraceae/metabolismo , Cobre/metabolismo , Fontes Hidrotermais/microbiologia , Alcanivoraceae/classificação , Alcanivoraceae/genética , Alcanivoraceae/isolamento & purificação , Açores , Genoma Bacteriano , Genômica , Anotação de Sequência Molecular , Filogenia
12.
Int J Syst Evol Microbiol ; 70(5): 3528-3533, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32392121

RESUMO

A Gram-stain-negative, rod-shaped, facultative anaerobic bacterium, designated strain 3539T, was isolated from coastal sediment of Weihai, PR China. Optimal growth occurred at 28 °C, pH 7.5-8.0 and in the presence of 3.0 % (w/v) NaCl. Results of phylogenetic analysis based on 16S rRNA gene sequences revealed that strain 3539T formed a robust clade with members of the genus Marinicella and was closely related to Marinicella litoralis JCM 16154T, Marinicella sediminis F2T and Marinicella pacifica sw153T with 97.7, 96.2 and 95.4 % sequence similarity, respectively. The average amino acid identity, percentage of conserved proteins, average nucleotide identity and digital DNA-DNA hybridization values between strain 3539T and M. litoralis JCM 16154T were 64.9, 68.3, 72.8 and 18.9 %, respectively. The genomic DNA G+C content of strain 3539T was 42.0 mol%. The dominant respiratory quinone was ubiquinone-8, and the major fatty acids were iso-C15 : 0 and summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c). The polar lipids of strain 3539T consisted of phosphatidyldimethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, one unidentified aminophospholipid, one unidentified lipid and three unidentified phospholipids. Based on the combination of phylogenetic, phenotypic and chemotaxonomic data, strain 3539T is considered to represent a novel species within the genus Marinicella in he family Alcanivoracaceae, for which the name Marinicella rhabdoformis sp. nov. is proposed. The type strain of the new species is 3539T (=KCTC 72414T=MCCC 1H00388T).


Assuntos
Alcanivoraceae/classificação , Sedimentos Geológicos/microbiologia , Filogenia , Água do Mar/microbiologia , Alcanivoraceae/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/química
13.
Appl Environ Microbiol ; 86(9)2020 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-32111588

RESUMO

Biocatalysis has emerged as an important tool in synthetic organic chemistry enabling the chemical industry to execute reactions with high regio- or enantioselectivity and under usually mild reaction conditions while avoiding toxic waste. Target substrates and products of reactions catalyzed by carboxylic ester hydrolases are often poorly water soluble and require organic solvents, whereas enzymes are evolved by nature to be active in cells, i.e., in aqueous rather than organic solvents. Therefore, biocatalysts that withstand organic solvents are urgently needed. Current strategies to identify such enzymes rely on laborious tests carried out by incubation in different organic solvents and determination of residual activity. Here, we describe a simple assay useful for screening large libraries of carboxylic ester hydrolases for resistance and activity in water-miscible organic solvents. We have screened a set of 26 enzymes, most of them identified in this study, with four different water-miscible organic solvents. The triglyceride tributyrin was used as a substrate, and fatty acids released by enzymatic hydrolysis were detected by a pH shift indicated by the indicator dye nitrazine yellow. With this strategy, we succeeded in identifying a novel highly organic-solvent-tolerant esterase from Pseudomonas aestusnigri In addition, the newly identified enzymes were tested with sterically demanding substrates, which are common in pharmaceutical intermediates, and two enzymes from Alcanivorax borkumensis were identified which outcompeted the gold standard ester hydrolase CalB from Candida antarctica IMPORTANCE Major challenges hampering biotechnological applications of esterases include the requirement to accept nonnatural and chemically demanding substrates and the tolerance of the enzymes toward organic solvents which are often required to solubilize such substrates. We describe here a high-throughput screening strategy to identify novel organic-solvent-tolerant carboxylic ester hydrolases (CEs). Among these enzymes, CEs active against water-insoluble bulky substrates were identified. Our results thus contribute to fostering the identification and biotechnological application of CEs.


Assuntos
Alcanivoraceae/enzimologia , Hidrolases de Éster Carboxílico/metabolismo , Técnicas de Química Sintética , Pseudomonas/enzimologia , Solventes/química , Ensaios de Triagem em Larga Escala
14.
Environ Microbiol ; 22(4): 1356-1369, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32079039

RESUMO

Pristine marine environments are highly oligotrophic ecosystems populated by well-established specialized microbial communities. Nevertheless, during oil spills, low-abundant hydrocarbonoclastic bacteria bloom and rapidly prevail over the marine microbiota. The genus Alcanivorax is one of the most abundant and well-studied organisms for oil degradation. While highly successful under polluted conditions due to its specialized oil-degrading metabolism, it is unknown how they persist in these environments during pristine conditions. Here, we show that part of the Alcanivorax genus, as well as oils, has an enormous potential for biodegrading aliphatic polyesters thanks to a unique and abundantly secreted alpha/beta hydrolase. The heterologous overexpression of this esterase proved a remarkable ability to hydrolyse both natural and synthetic polyesters. Our findings contribute to (i) better understand the ecology of Alcanivorax in its natural environment, where natural polyesters such as polyhydroxyalkanoates (PHA) are produced by a large fraction of the community and, hence, an accessible source of carbon and energy used by the organism in order to persist, (ii) highlight the potential of Alcanivorax to clear marine environments from polyester materials of anthropogenic origin as well as oils, and (iii) the discovery of a new versatile esterase with a high biotechnological potential.


Assuntos
Alcanivoraceae/enzimologia , Biodegradação Ambiental , Óleos/metabolismo , Alcanivoraceae/classificação , Alcanivoraceae/metabolismo , Biotecnologia , Ecossistema , Poluição por Petróleo , Poliésteres/metabolismo , Poli-Hidroxialcanoatos/metabolismo
15.
Int J Mol Sci ; 21(4)2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-32053975

RESUMO

The environmental accumulation of plastics worldwide is a consequence of the durability of the material. Alternative polymers, marketed as biodegradable, present a potential solution to mitigate their ecological damage. However, understanding of biodegradability has been hindered by a lack of reproducible testing methods. We developed a novel method to evaluate the biodegradability of plastic samples based on the monitoring of bacterial respiration in aqueous media via the quantification of CO2 produced, where the only carbon source available is from the polymer. Rhodococcus rhodochrous and Alcanivorax borkumensis were used as model organisms for soil and marine systems, respectively. Our results demonstrate that this approach is reproducible and can be used with a variety of plastics, allowing comparison of the relative biodegradability of the different materials. In the case of low-density polyethylene, the study demonstrated a clear correlation between the molecular weight of the sample and CO2 released, taken as a measure of biodegradability.


Assuntos
Alcanivoraceae/metabolismo , Dióxido de Carbono/metabolismo , Poluentes Ambientais/metabolismo , Plásticos/metabolismo , Rhodococcus/metabolismo , Biodegradação Ambiental , Monitoramento Ambiental/métodos , Polietileno/metabolismo , Eliminação de Resíduos
16.
Environ Sci Pollut Res Int ; 26(34): 35131-35139, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31680200

RESUMO

Water column and sediment samples were collected in the southern Gulf of Mexico (GoMex) during 3 oceanographic cruises: XIXIMI-04 (September 2015), XIXIMI-05 (June 2016), and XIXIMI-06 (August 2017). DNA that was extracted from the samples was analyzed by qPCR to detect and quantify bacterial groups that have been reported to metabolize alkanes (Alcanivorax) and aromatic hydrocarbons (Cycloclasticus) and are involved in methane production (Methanomicrobiales). The results were then analyzed with regard to the water masses that are currently detected in the GoMex. Generally, we observed a decrease in the proportion of Alcanivorax and a rise in those of Cycloclasticus and Methanomicrobiales in samples from the surface to deep waters and in sediment samples. Scatterplots of the results showed that the relative abundance of the 3 groups was higher primarily from the surface to 1000 m, but the levels of Cycloclasticus and Methanomicrobiales were high in certain water samples below 1000 m and in sediments. In conclusion, oil-degrading bacteria are distributed widely from the surface to deep waters and sediments throughout the southern GoMex, representing a potential inoculum of bacteria for various hydrocarbon fractions that are ready for proliferation and degradation in the event of an oil spill from the seafloor or along the water column.


Assuntos
Biodegradação Ambiental , Sedimentos Geológicos/microbiologia , Microbiologia da Água , Alcanivoraceae , Alcanos/análise , Bactérias/metabolismo , Monitoramento Ambiental , Golfo do México , Hidrocarbonetos/análise , Methanomicrobiales , Petróleo/metabolismo , Poluição por Petróleo/análise , Poluentes Químicos da Água/análise
17.
J Hazard Mater ; 380: 120899, 2019 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-31326835

RESUMO

Most plastics are released to the environment in landfills and around 32% end up in the sea, inducing large ecological and health impacts. The plastics constitute a physical substrate and potential carbon source for microorganisms. The present study compares the structures of bacterial communities from floating plastics, sediment-associated plastics and sediments from the Mediterranean Sea. The 16S rRNA microbiome profiles of surface and sediment plastic-associated microbial biofilms from the same geographic location differ significantly, with the omnipresence of Bacteroidetes and Gammaproteobacteria. Our research confirmed that plastisphere hosts microbial communities were environmental distinct niche. In parallel, this study used environmental samples to investigate the enrichment of potential plastic-degrading bacteria with Low Density PolyEthylene (LDPE), PolyEthylene Terephthalate (PET) and PolyStyrene (PS) plastics as the sole carbon source. In this context, we showed that the bacterial community composition is clearly plastic nature dependent. Hydrocarbon-degrading bacteria such as Alcanivorax, Marinobacter and Arenibacter genera are enriched with LDPE and PET, implying that these bacteria are potential players in plastic degradation. Finally, our data showed for the first time the ability of Alcanivorax borkumensis to form thick biofilms specifically on LDPE and to degrade this petroleum-based plastic.


Assuntos
Alcanivoraceae/metabolismo , Ecossistema , Plásticos , Polietileno/metabolismo , Água do Mar/microbiologia , Biodegradação Ambiental
18.
Environ Microbiol ; 21(7): 2347-2359, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30951249

RESUMO

Alcanivorax borkumensis SK2T is an important obligate hydrocarbonoclastic bacterium (OHCB) that can dominate microbial communities following marine oil spills. It possesses the ability to degrade branched alkanes which provides it a competitive advantage over many other marine alkane degraders that can only degrade linear alkanes. We used LC-MS/MS shotgun proteomics to identify proteins involved in aerobic alkane degradation during growth on linear (n-C14 ) or branched (pristane) alkanes. During growth on n-C14 , A. borkumensis expressed a complete pathway for the terminal oxidation of n-alkanes to their corresponding acyl-CoA derivatives including AlkB and AlmA, two CYP153 cytochrome P450s, an alcohol dehydrogenase and an aldehyde dehydrogenase. In contrast, during growth on pristane, an alternative alkane degradation pathway was expressed including a different cytochrome P450, an alcohol oxidase and an alcohol dehydrogenase. A. borkumensis also expressed a different set of enzymes for ß-oxidation of the resultant fatty acids depending on the growth substrate utilized. This study significantly enhances our understanding of the fundamental physiology of A. borkumensis SK2T by identifying the key enzymes expressed and involved in terminal oxidation of both linear and branched alkanes. It has also highlights the differential expression of sets of ß-oxidation proteins to overcome steric hinderance from branched substrates.


Assuntos
Alcanivoraceae/enzimologia , Alcanivoraceae/metabolismo , Alcanos/metabolismo , Alcanivoraceae/crescimento & desenvolvimento , Álcool Desidrogenase/genética , Oxirredutases do Álcool/genética , Biodegradação Ambiental , Cromatografia Líquida , Sistema Enzimático do Citocromo P-450/genética , Ácidos Graxos/metabolismo , Proteômica , Espectrometria de Massas em Tandem , Terpenos/metabolismo
19.
Microbes Environ ; 34(1): 104-107, 2019 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-30773505

RESUMO

Alcanivorax borkumensis is a ubiquitous marine bacterium that utilizes alkanes as a sole carbon source. We observed two phenotypes in the A. borkumensis SK2 type strain: rough (R) and smooth (S) types. The S type exhibited lower motility and higher polysaccharide production than the R type. Full genome sequencing revealed a mutation in the S type involved in cyclic-di-GMP production. The present results suggest that higher c-di-GMP levels in the S type control the biofilm forming behavior of this bacterium in a manner commensurate with other Gram-negative bacteria.


Assuntos
Alcanivoraceae/fisiologia , Proteínas de Bactérias/genética , Biofilmes/crescimento & desenvolvimento , GMP Cíclico/análogos & derivados , Alcanivoraceae/genética , Alcanivoraceae/metabolismo , Alcanos/metabolismo , Proteínas de Bactérias/metabolismo , GMP Cíclico/metabolismo , Regulação Bacteriana da Expressão Gênica , Genoma Bacteriano/genética , Fenótipo , Mutação Puntual , Polissacarídeos Bacterianos/biossíntese
20.
Appl Environ Microbiol ; 85(3)2019 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-30446553

RESUMO

In subduction zones, serpentinization and biological processes may release alkanes to the deep waters, which would probably result in the rapid spread of Alcanivorax However, the timing and area of the alkane distribution and associated enrichment of alkane-degrading microbes in the dark world of the deep ocean have not been explored. In this study, we report the richness (up to 17.8%) of alkane-degrading bacteria, represented by Alcanivorax jadensis, in deep water samples obtained at 3,000 to 6,000 m in the Mariana Trench in two cruises. The relative abundance of A. jadensis correlated with copy numbers of functional almA and alkB genes, which are involved in alkane degradation. In these water samples, we detected a high flux of alkanes, which probably resulted in the prevalence of A. jadensis in the deep waters. Contigs of A. jadensis were binned from the metagenomes for examination of alkane degradation pathways and deep sea-specific pathways, which revealed a lack of nitrate and nitrite dissimilatory reduction in our A. jadensis strains. Comparing the results for the two cruises conducted close to each other, we suggest periodic release of alkanes that may spread widely but periodically in the trench. Distribution of alkane-degrading bacteria in the world's oceans suggests the periodic and remarkable contributions of Alcanivorax to the deep sea organic carbon and nitrogen sources.IMPORTANCE In the oligotrophic environment of the Mariana Trench, alkanes as carbohydrates are important for the ecosystem, but their spatial and periodic spreading in deep waters has never been reported. Alkane-degrading bacteria such as Alcanivorax spp. are biological signals of the alkane distribution. In the present study, Alcanivorax was abundant in some waters, at depths of up to 6,000 m, in the Mariana Trench. Genomic, transcriptomic, and chemical analyses provide evidence for the presence and activities of Alcanivorax jadensis in deep sea zones. The periodic spreading of alkanes, probably from the subductive plates, might have fundamentally modified the local microbial communities, as well as perhaps the deep sea microenvironment.


Assuntos
Alcanivoraceae/metabolismo , Alcanos/metabolismo , Água do Mar/microbiologia , Alcanivoraceae/classificação , Alcanivoraceae/genética , Alcanivoraceae/isolamento & purificação , Alcanos/análise , Biodegradação Ambiental , Ecossistema , Nitratos/metabolismo , Nitritos/metabolismo , Filogenia , Água do Mar/química
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