RESUMO
Quartzite caves located on table-top mountains (tepuis) in the Guyana Shield, are ancient, remote, and pristine subterranean environments where microbes have evolved peculiar metabolic strategies to thrive in silica-rich, slightly acidic and oligotrophic conditions. In this study, we explored the culturable fraction of the microbiota inhabiting the (ortho)quartzite cave systems in Venezuelan tepui (remote table-top mountains) and we investigated their metabolic and enzymatic activities in relation with silica solubilization and extracellular hydrolytic activities as well as the capacity to produce antimicrobial compounds. Eighty microbial strains were isolated with a range of different enzymatic capabilities. More than half of the isolated strains performed at least three enzymatic activities and four bacterial strains displayed antimicrobial activities. The antimicrobial producers Paraburkholderia bryophila CMB_CA002 and Sphingomonas sp. MEM_CA187, were further analyzed by conducting chemotaxonomy, phylogenomics, and phenomics. While the isolate MEM_CA187 represents a novel species of the genus Sphingomonas, for which the name Sphingomonas imawarii sp. nov. is proposed, P. bryophila CMB_CA002 is affiliated with a few strains of the same species that are antimicrobial producers. Chemical analyses demonstrated that CMB_CA002 produces ditropolonyl sulfide that has a broad range of activity and a possibly novel siderophore. Although the antimicrobial compounds produced by MEM_CA187 could not be identified through HPLC-MS analysis due to the absence of reference compounds, it represents the first soil-associated Sphingomonas strain with the capacity to produce antimicrobials. This work provides first insights into the metabolic potential present in quartzite cave systems pointing out that these environments are a novel and still understudied source of microbial strains with biotechnological potential.
Assuntos
Bactérias , Cavernas , Filogenia , RNA Ribossômico 16S , Cavernas/microbiologia , RNA Ribossômico 16S/genética , Bactérias/classificação , Bactérias/metabolismo , Bactérias/isolamento & purificação , Bactérias/genética , Dióxido de Silício/química , Microbiota , Venezuela , Sphingomonas/metabolismo , Sphingomonas/isolamento & purificação , Sphingomonas/classificação , Sphingomonas/genética , Biotecnologia/métodos , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Microbiologia do Solo , DNA Bacteriano/genéticaRESUMO
Electronic waste (E-Waste) is consumed at high speed in the world. These residues contain metals that increase their price each year, generating new research on the ability of microorganisms to recover the metals from these wastes. Therefore, this work evaluated the biologic lixiviation of Cu, Ag and Au from printed circuit boards (PCB) of mobile phones by three strains of Aspergillus niger, Candida orthopsilosis, Sphingomonas sp. and their respective consortia, in addition to leaching with citric acid. The microorganisms were cultured in mineral media with 0.5 g of PCB, and the treatments with 1M citric acid were added the same amount of PCB. All treatments were incubated for 35 days at room temperature. The results showed that Sphingomonas sp. MXB8 and the consortium of C. orthopsilosis MXL20 and A. niger MXPE6 can increase their dry biomass by 147% and 126%, respectively, in the presence of PCB. In the bioleaching of metals, the inoculation of A. niger MXPE6, the consortium of Sphingomonas sp. MXB8/C. orthopsilosis MXL20 and Sphingomonas sp. MXB8 leached 54%, 44.2% and 35.8% of Ag. The consortium of A. niger MX5 and A. niger MXPE6 showed a leaching of 0.53% of Au. A. niger MX5 leaching 2.8% Cu. Citric acid increased Cu leaching by 280% compared to treatments inoculated with microorganisms. Although further research is required, A. niger MXPE6 and the consortium of Sphingomonas sp. MXB8/C. orthopsilosis MXL20 could be an alternative to recover Ag from PCB of mobile phones.
Assuntos
Telefone Celular , Cobre/metabolismo , Resíduo Eletrônico , Ouro/metabolismo , Consórcios Microbianos , Prata/metabolismo , Aspergillus niger/metabolismo , Candida/metabolismo , Ácido Cítrico/química , Reciclagem/métodos , Sphingomonas/metabolismoRESUMO
In order to study the mechanisms regulating the phenanthrene degradation pathway and the intermediate-metabolite accumulation in strain S. paucimobilis 20006FA, we sequenced the genome and compared the genome-based predictions to experimental proteomic analyses. Physiological studies indicated that the degradation involved the salicylate and protocatechuate pathways, reaching 56.3% after 15 days. Furthermore, the strain degraded other polycyclic aromatic hydrocarbons (PAH) such as anthracene (13.1%), dibenzothiophene (76.3%), and fluoranthene. The intermediate metabolite 1-hydroxy-2-naphthoic acid (HNA) accumulated during phenanthrene catabolism and inhibited both bacterial growth and phenanthrene degradation, but exogenous-HNA addition did not affect further degradation. Genomic analysis predicted 126 putative genes encoding enzymes for all the steps of phenanthrene degradation, which loci could also participate in the metabolism of other PAH. Proteomic analysis identified enzymes involved in 19 of the 23 steps needed for the transformation of phenanthrene to trichloroacetic-acid intermediates that were upregulated in phenanthrene cultures relative to the levels in glucose cultures. Moreover, the protein-induction pattern was temporal, varying between 24 and 96 h during phenanthrene degradation, with most catabolic proteins being overexpressed at 96 h-e. g., the biphenyl dioxygenase and a multispecies (2Fe-2S)-binding protein. These results provided the first clues about regulation of expression of phenanthrene degradative enzymes in strain 20006FA and enabled an elucidation of the metabolic pathway utilized by the bacterium. To our knowledge the present work represents the first investigation of genomic, proteomic, and physiological studies of a PAH-degrading Sphingomonas strain.
Assuntos
Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Proteoma/metabolismo , Proteômica , Sphingomonas/enzimologia , Sphingomonas/genética , Sphingomonas/metabolismo , Antracenos/metabolismo , Proteínas de Bactérias/genética , Biodegradação Ambiental , Simulação por Computador , DNA Bacteriano , Dioxigenases/metabolismo , Fluorenos/metabolismo , Glucose/metabolismo , Hidroxibenzoatos/metabolismo , Redes e Vias Metabólicas/genética , Redes e Vias Metabólicas/fisiologia , Naftóis/metabolismo , Fenantrenos/metabolismo , Salicilatos/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Sphingomonas/crescimento & desenvolvimento , Tiofenos/metabolismo , Ácido Tricloroacético/metabolismo , Sequenciamento Completo do GenomaRESUMO
Abstract Members of the Sphingomonas genus are often isolated from petroleum-contaminated soils due to their unique abilities to degrade polycyclic aromatic hydrocarbons (PAHs), which are important for in situ bioremediation. In this study, a combined phenotypic and genotypic approach using streptomycin-containing medium and Sphingomonas -specific PCR was developed to isolate and identify culturable Sphingomonas strains present in petroleum-contaminated soils in the Shenfu wastewater irrigation zone. Of the 15 soil samples examined, 12 soils yielded yellow streptomycin-resistant colonies. The largest number of yellow colony-forming units (CFUs) could reach 105 CFUs g-1 soil. The number of yellow CFUs had a significant positive correlation (p < 0.05) with the ratio of PAHs to total petroleum hydrocarbons (TPH), indicating that Sphingomonas may play a key role in degrading the PAH fraction of the petroleum contaminants at this site. Sixty yellow colonies were selected randomly and analyzed by colony PCR using Sphingomonas -specific primers, out of which 48 isolates had PCR-positive signals. The 48 positive amplicons generated 8 distinct restriction fragment length polymorphism (RFLP) patterns, and 7 out of 8 phylotypes were identified as Sphingomonas by 16S rRNA gene sequencing of the representative strains. Within these 7 Sphingomonas strains, 6 strains were capable of using fluorene as the sole carbon source, while 2 strains were phenanthrene-degrading Sphingomonas. To the best of our knowledge, this is the first report to evaluate the relationship between PAHs contamination levels and culturable Sphingomonas in environmental samples.
Assuntos
Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Sphingomonas/isolamento & purificação , Sphingomonas/metabolismo , Filogenia , Biodegradação Ambiental , Petróleo/análise , China , Sphingomonas/classificação , Sphingomonas/genéticaRESUMO
Members of the Sphingomonas genus are often isolated from petroleum-contaminated soils due to their unique abilities to degrade polycyclic aromatic hydrocarbons (PAHs), which are important for in situ bioremediation. In this study, a combined phenotypic and genotypic approach using streptomycin-containing medium and Sphingomonas-specific PCR was developed to isolate and identify culturable Sphingomonas strains present in petroleum-contaminated soils in the Shenfu wastewater irrigation zone. Of the 15 soil samples examined, 12 soils yielded yellow streptomycin-resistant colonies. The largest number of yellow colony-forming units (CFUs) could reach 10(5)CFUsg(-1)soil. The number of yellow CFUs had a significant positive correlation (p<0.05) with the ratio of PAHs to total petroleum hydrocarbons (TPH), indicating that Sphingomonas may play a key role in degrading the PAH fraction of the petroleum contaminants at this site. Sixty yellow colonies were selected randomly and analyzed by colony PCR using Sphingomonas-specific primers, out of which 48 isolates had PCR-positive signals. The 48 positive amplicons generated 8 distinct restriction fragment length polymorphism (RFLP) patterns, and 7 out of 8 phylotypes were identified as Sphingomonas by 16S rRNA gene sequencing of the representative strains. Within these 7 Sphingomonas strains, 6 strains were capable of using fluorene as the sole carbon source, while 2 strains were phenanthrene-degrading Sphingomonas. To the best of our knowledge, this is the first report to evaluate the relationship between PAHs contamination levels and culturable Sphingomonas in environmental samples.
Assuntos
Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Sphingomonas/isolamento & purificação , Sphingomonas/metabolismo , Biodegradação Ambiental , China , Petróleo/análise , Filogenia , Sphingomonas/classificação , Sphingomonas/genéticaRESUMO
AIMS: The objective of this study was to apply the knowledge-based approach to the selection of an inoculum to be used in bioaugmentation processes to facilitate phenanthrene degradation in phenanthrene- and Cr(VI)-co-contaminated soils. METHODS AND RESULTS: The bacterial community composition of phenanthrene and phenanthrene- and Cr(VI)-co-contaminated microcosms, determined by denaturing gradient gel electrophoresis analysis, showed that members of the Sphingomonadaceae family were the predominant micro-organisms. However, the Cr(VI) contamination produced a selective change of predominant Sphingomonas species, and in co-contaminated soil microcosms, a population closely related to Sphingomonas paucimobilis was naturally selected. The bioaugmentation process was carried out using the phenanthrene-degrading strain S. paucimobilis 20006FA, isolated and characterized in our laboratory. Although the strain showed a low Cr(VI) resistance (0·250 mmol l⻹); in liquid culture, it was capable of reducing chromate and degrading phenanthrene simultaneously. CONCLUSION: The inoculation of this strain managed to moderate the effect of the presence of Cr(VI), increasing the biological activity and phenanthrene degradation rate in co-contaminated microcosm. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, we have applied a novel approach to the selection of the adequate inoculum to enhance the phenanthrene degradation in phenanthrene- and Cr(VI)-co-contaminated soils.
Assuntos
Cromo/metabolismo , Fenantrenos/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Sphingomonas/isolamento & purificação , Sphingomonas/metabolismo , Bactérias/efeitos dos fármacos , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Biodegradação Ambiental , Filogenia , Sphingomonas/efeitos dos fármacos , Sphingomonas/genéticaRESUMO
The present study describes the phenanthrene-degrading activity of Sphingomonas paucimobilis 20006FA and its ability to promote the bioavailability of phenanthrene. S. paucimobilis 20006FA was isolated from a phenanthrene-contaminated soil microcosm. The strain was able to grow in liquid mineral medium saturated with phenanthrene as the sole carbon source, showing high phenanthrene elimination (52.9% of the supplied phenanthrene within 20 days). The accumulation of 1-hydroxy-2-naphthoic acid and salicylic acid as major phenanthrene metabolites and the capacity of the strain to grow with sodium salicylate as the sole source of carbon and energy indicated that the S. paucimobilis 20006FA possesses a complete phenanthrene degradation pathway. However, under the studied conditions, the strain was able to mineralize only the 10% of the consumed phenanthrene. Investigations on the cell ability to promote bioavailability of phenanthrene showed that the S. paucimobilis strain 20006FA exhibited low cell hydrophobicity (0.13), a pronounced chemotaxis toward phenanthrene, and it was able to reduce the surface tension of mineral liquid medium supplemented with phenanthrene as sole carbon source. Scanning electron micrographs revealed that: (1) in suspension cultures, cells formed flocks and showed small vesicles on the cell surface and (2) cells were also able to adhere to phenanthrene crystals and to produce biofilms. Clearly, the strain seems to exhibit two different mechanisms to enhance phenanthrene bioavailability: biosurfactant production and adhesion to the phenanthrene crystals.
Assuntos
Fenantrenos/metabolismo , Microbiologia do Solo , Sphingomonas/metabolismo , Biodegradação Ambiental , Disponibilidade Biológica , Carbono/metabolismo , Meios de Cultura , Interações Hidrofóbicas e Hidrofílicas , Microscopia Eletrônica de Varredura , Naftóis/metabolismo , Ácido Salicílico/metabolismo , Sphingomonas/ultraestrutura , Tensoativos/metabolismoRESUMO
So far, the occurrence of nitrogen-fixing Sphingomonas bacteria has been restricted to three strains of Sphingomonas azotifigens. In this work, a group of 46 Sphingomonas-like isolates, which originated from two rice varieties grown in two soils in Brazil, were characterized based on morphological, physiological and genetic analyses. The PCR genus specifically applied indicated that all 46 isolates belonged to the Sphingomonas genus and confirmed the results based on the yellow pigment of the colonies grown on potato agar medium and the BIOLOG data. It was also observed that 22 isolates are nitrogen-fixing bacteria as determined by the acetylene reduction method and confirmed by nifH gene detection. The genetic diversity based on the 16S rRNA analysis (amplified rDNA restriction analysis) showed that the isolates formed two distinct groups at a similarity value of 60%. Furthermore, five clusters at 60% similarity were observed with the 16S-23S intergenic space (ribosomal intergenic space analysis) analysis. Sequencing of the 16S rRNA gene and nifH fragments showed that most of the 22 nitrogen-fixing isolates formed clusters apart from that of the S. azotifigens. This is the first report on the occurrence of nitrogen-fixing Sphingomonas bacteria associated with rice grown in Brazil.
Assuntos
Variação Genética , Fixação de Nitrogênio , Oryza/microbiologia , Sphingomonas/classificação , Brasil , DNA Ribossômico/análise , DNA Espaçador Ribossômico/análise , Dados de Sequência Molecular , Oryza/crescimento & desenvolvimento , Oxirredutases , Reação em Cadeia da Polimerase/métodos , RNA Ribossômico 16S/genética , RNA Ribossômico 23S/genética , Mapeamento por Restrição , Análise de Sequência de DNA , Sphingomonas/genética , Sphingomonas/isolamento & purificação , Sphingomonas/metabolismoRESUMO
The effects of the inoculant strain Sphingomonas paucimobilis 20006FA (isolated from a phenanthrene-contaminated soil) on the dynamics and structure of microbial communities and phenanthrene elimination rate were studied in soil microcosms artificially contaminated with phenanthrene. The inoculant managed to be established from the first inoculation as it was evidenced by denaturing gradient gel electrophoresis analysis, increasing the number of cultivable heterotrophic and PAH-degrading cells and enhancing phenanthrene degradation. These effects were observed only during the inoculation period. Nevertheless, the soil biological activity (dehydrogenase activity and CO(2) production) showed a late increase. Whereas gradual and successive changes in bacterial community structures were caused by phenanthrene contamination, the inoculation provoked immediate, significant, and stable changes on soil bacterial community. In spite of the long-term establishment of the inoculated strain, at the end of the experiment, the bioaugmentation did not produce significant changes in the residual soil phenanthrene concentration and did not improve the residual effects on the microbial soil community.
Assuntos
Bactérias/crescimento & desenvolvimento , Fenantrenos/metabolismo , Microbiologia do Solo , Sphingomonas/metabolismo , Bactérias/genética , Bactérias/metabolismo , Biodegradação Ambiental , Dióxido de Carbono/metabolismo , Cromatografia Gasosa , Contagem de Colônia Microbiana , DNA Bacteriano/genética , Eletroforese , Dados de Sequência Molecular , Oxirredutases/metabolismo , Fenantrenos/análise , Reação em Cadeia da Polimerase , Poluentes do Solo/metabolismo , Sphingomonas/genética , Sphingomonas/isolamento & purificaçãoRESUMO
This work was aimed at the production and rheological characterization of biopolymer by Sphingomonas capsulata ATCC 14666, using conventional and industrial media. The productivity reached the maximum of 0.038 g/L x h, at 208 rpm and 4% (w/v) of sucrose. For this condition, different concentrations of industrial medium were tested (2.66, 4, 6, and 8%). The best productivity was obtained using pretreated molasses 8% (w/v) (0.296 g/L x h), residue of textured soybean protein 6% (wt/v) (0.244 g/L x h) and crude molasses 8% (w/v) (0.192 g/L x h), respectively. Apparent viscosity presented similar results when compared with those in the literature for other biopolymers.