RESUMO
Recent attention on the detrimental effects of pharmaceutically active compounds (PhACs) in natural water has spurred researchers to develop advanced wastewater treatment methods. Carbamazepine (CBZ), a widely recognized anticonvulsant, has often been a primary focus in numerous studies due to its prevalence and resistance to breaking down. This study aims to explore the effectiveness of a bio-electrochemical system in breaking down CBZ in polluted water and to assess the potential harmful effects of the treated wastewater. The results revealed bio-electro degradation process demonstrated a collaborative effect, achieving the highest CBZ degradation compared to electrodegradation and biodegradation techniques. Notably, a maximum CBZ degradation efficiency of 92.01% was attained using the bio-electrochemical system under specific conditions: Initial CBZ concentration of 60 mg/L, pH level at 7, 0.5% (v/v) inoculum dose, and an applied potential of 10 mV. The degradation pathway established by identifying intermediate products via High-Performance Liquid Chromatography-Mass Spectrometry, revealed the complete breakdown of CBZ without any toxic intermediates or end products. This finding was further validated through in vitro and in vivo toxicity assays, confirming the absence of harmful remnants after the degradation process.
Assuntos
Biodegradação Ambiental , Carbamazepina , Poluentes Químicos da Água , Carbamazepina/toxicidade , Poluentes Químicos da Água/toxicidade , Águas Residuárias/química , AnimaisRESUMO
Bisphenol A (BpA) is an endocrine-disrupting substance commonly found in plastics and resins. It is reported that BpA exposure induces lipid accumulation in humans, similar to obesogenic compounds. The main objective of this study is to investigate the removal of BpA using Lactiplantibacillus sp. D10-2, and to examine its potential for reducing BpA-induced lipid accumulation in 3T3-L1 cell line model. The heat-dried cells of Lactiplantibacillus sp. D10-2 showed 69.7% removal efficiency for initial BpA concentration of 10 µg/mL, which was 30.5% higher than the live cells. The absence of metabolites or intermediates in BpA removal studies indicates that the Lactiplantibacillus sp. D10-2 strain removed BpA by adsorption process. The hydrophobic interactions of heat-dried Lactiplantibacillus sp. D10-2 cells were observed to be higher with 33.7% compared to live cells (15.0%), suggesting a stronger ability to bind with BpA. Although the BpA binding onto Lactiplantibacillus sp. D10-2 was not affected by pH, it was confirmed that as the temperature increases, the binding ability got decreased due to mass transfer and diffusion of BpA molecules. Treatment with Lactiplantibacillus sp. D10-2 (0.1, 0.25, 0.5, 1%) reduced lipid accumulation by 61.7, 58.0, 52.7 and 60.4% in 3T3-L1 cells exposed with BpA. In addition, it was confirmed that Lactiplantibacillus sp. D10-2 treatment suppressed the protein expression levels of lipogenesis-related PPARγ and C/EBPα in 3T3-L1 cells. The results of the study suggest that the Lactiplantibacillus sp. D10-2 strain can remove BpA and reduce BpA-accelerated lipid accumulation in 3T3-L1 cells.
RESUMO
AIM: To assess the effectiveness of Lentilactobacillus parafarraginis A6-2 cell lysate for the removal of aluminum (Al), which induces neurotoxicity, and its protective effect at cellular level. METHODS AND RESULTS: The cell lysate of the selected L. parafarraginis A6-2 strain demonstrated superior Al removal compared to live or dead cells. The Al removal efficiency of L. parafarraginis A6-2 cell lysate increased with decreasing pH and increasing temperature, primarily through adsorption onto peptidoglycan. Neurotoxicity mitigation potential of L. parafarraginis A6-2 was evaluated using C6 glioma cells. C6 cells exposed with increasing concentration of Al led to elevated toxicity and inflammation, which were gradually alleviated upon treatment with L. parafarraginis A6-2. Moreover, Al-induced oxidative stress in C6 cells showed a concentration-dependent reduction upon treatment with L. parafarraginis A6-2. CONCLUSIONS: This study demonstrated that L. parafarraginis A6-2 strain, particularly in its lysate form, exhibited enhanced capability for Al removal. Furthermore, it effectively mitigated Al-induced toxicity, inflammation, and oxidative stress.
Assuntos
Alumínio , Estresse Oxidativo , Humanos , Alumínio/toxicidade , Inflamação , Anti-Inflamatórios/farmacologiaRESUMO
Enterococcus gallinarum (JT-02) isolated and identified from the animal farm waste sludge was found to be capable of biodegrading p-nitrophenol (PNP), an organic compound used to manufacture drugs, fungicides, insecticides, dyes, and to darken leather. The intention of this study was to optimize the biodegradation by finding the optimal conditions for the specific strain through single-factor experiments. The bacterial strain was grown in Luria Bertani broth and various parameters were optimized to achieve the prime settings for the p-nitrophenol (PNP) biodegradation. The results indicated that the best setups for the biodegradation by the strain JT-02 was 100 mg/L of PNP; pH 7; 30 °C; 150 rpm in a shaker incubator and 3% (v/v) of inoculum dose. Once the optimal conditions were found, the bacteria were capable of degrading p-nitrophenol (98.21%) in 4 days. Intermediates produced during PNP biodegradation were identified using High Performance Liquid Chromatography (HPLC) analysis and the biodegradation pathway was elucidated. Phytotoxicity studies were carried out with Vigna radiata seeds to confirm the applicability and efficiency of PNP biodegradation.
Assuntos
Enterococcus , Esgotos , Animais , Esgotos/microbiologia , Fazendas , Bactérias/metabolismoRESUMO
WO3/Zeolite/V2O5 (TZV) composite synthesized through co-precipitation was used for the degradation of Bisphenol-A (BpA). XRD and Raman spectra were employed to ascertain the crystallinity of the composite. The pristine nature of the compound without any free particles over the zeolite surface was established through FESEM, thus, substantiating the composite character of the material. The enhancement in activity after doping with WO3 was ascertained by DRS-UV. Photocatalytic degradation studies clearly established the superiority of TZV 10 over bare V2O5. Complete BpA degradation (100%) was attained at 50 min of incubation with 0.75 g/L TZV-10 in acidic medium (pH 3) for an initial BpA concentration of 100 mg/L. HPLC-MS/MS analysis was used to decipher the degradation pathway. The catalyst was stable even after 9 cycles. Phytotoxicity studies and lake water treatment results proved the environmental efficiency of the synthesized material.
Assuntos
Zeolitas , Compostos Benzidrílicos/toxicidade , Catálise , Fenóis/química , Espectrometria de Massas em TandemRESUMO
Vinegar is a common food additive produced by acetic acid bacteria (AAB) during fermentation process. Low yield and long incubation time in conventional vinegar fermentation processes has inspired research in developing efficient fermentation techniques by the activation of AAB for acetic acid production. The present study intends to enhance vinegar production using acetic acid bacteria and light emitting diode (LED). A total of eight acetic acid bacteria were isolated from Korean traditional vinegar and assessed for vinegar production. Isolate AP01 exhibited maximum vinegar production and was identified as Acetobacter pasteurianus based on the 16S rRNA sequences. The optimum fermentation conditions for the isolate AP01 was incubation under static condition at 30 °C for 10 days with 6% initial ethanol concentration. Fermentation under red LED light exhibited maximum vinegar production (3.6%) compared to green (3.5%), blue (3.2%), white (2.2%), and non-LED lights (3.0%). Vinegar produced using red LED showed less toxicity to mouse macrophage cell line (RAW 264.7) and high inhibitory effects on nitric oxide and IL-6 production. The results confirmed that red LED light could be used to increase the yield and decrease incubation time in vinegar fermentation process.
Assuntos
Ácido Acético/metabolismo , Acetobacter/metabolismo , Acetobacter/genética , Acetobacter/efeitos da radiação , Fermentação , Microbiologia Industrial , Luz , RNA Ribossômico 16S/genéticaRESUMO
Bacillus bacteria have major utility in large-scale production of industrial enzymes, among which proteases have particular importance. B. subtilis B22, an aerobic and chemotrophic strain, was isolated from kimchi and identified by 16S rRNA gene sequencing. Extracellular protease production was determined in basic medium, with 1% (w/v) casein as substrate, by submerged fermentation at 37 °C under blue, green, red and white light-emitting diodes (LEDs), white fluorescent light and darkness. Fermentation under blue LEDs maximized protease production (110.79 ± 1.8 U/mL at 24 h). Various agricultural waste products enhanced production and groundnut oil cake yielded the most protease (334 ± 1.8 U/mL at 72 h). Activity and stability of the purified protease were optimum at pH 7-10 and 20-60 °C. Activity increased in the presence of Ca2+, Mg2+ and Mn2+, while Fe2+, Zn2+, Co2+ and Cu2+ moderated activity, and Ni2+ and Hg2+ inhibited activity. Activity was high (98%) in the presence of ethylenediaminetetraacetic acid (EDTA) but inhibited by phenylmethanesulfonyl fluoride (PMSF). The protease was unaffected by nonionic surfactants, tolerated an anionic surfactant and oxidizing agents, and was compatible with multiple organic solvents. These properties suggest utility of protease produced by B. subtilis B22 under blue LEDs for industrial applications.
Assuntos
Agricultura , Bacillus subtilis/crescimento & desenvolvimento , Proteínas de Bactérias/biossíntese , Luz , Peptídeo Hidrolases/biossíntese , Gerenciamento de ResíduosRESUMO
Light and bacteria can be used in combination to enhance secondary metabolite production during fermentation. Red yeast rice powder (RYRP) was inoculated with Bacillus subtilis (B2) isolated from freshwater seafood and incubated under light-emitting diodes (LEDs) of different colors (blue, green, red, white), fluorescent white light, and in darkness. Blue LED-mediated fermentation with B2 significantly enhanced production of phenolic compounds (68.4 ± 1 mg GAE/g DW) and flavonoids (51.7 ± 1 mg QE/g DW) compared to white light and darkness. Total antioxidant activity of RYRP extract after fermentation with B2 was > 77%; hydroxyl radical and superoxide scavenging were > 66%. DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) and ABTS (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid)) radical scavenging activities were 51% and > 67%, respectively. Reducing power was approximately twice that of extract from RYRP without B2. FTIR analysis showed a high content of hydroxyl, nitrile and carboxylic groups in the extract. Derivatives of cinnamic, benzoic and phophinodithioic acid, and quinazolinone were identified by GC-MS. Findings show that fermenting RYRP with B. subtilis B2 under blue LEDs enhances production of secondary metabolites, which should have applications in industrial fermentation processes.
Assuntos
Antioxidantes/metabolismo , Bacillus subtilis/crescimento & desenvolvimento , Produtos Biológicos/química , LuzRESUMO
A chemotrophic, aerobic bacterial strain, Bacillus subtilis B2, was used to produce amylase by submerged fermentation under different light sources. SDS-PAGE indicated that the 55 kDa enzyme belonged to the α-amylase group. B2 was incubated in basal media with 1% soluble starch (pH 7.0) under blue, green, red, and white light-emitting diodes (LEDs), and white fluorescent light. Fermentation under blue LEDs maximized amylase production (180.59 ± 1.6 U/mL at 24 h). Production at 48 h increased to 310.56 ± 1.6 U/mL with 5% glucose as a simple carbon source and to 300.51 ± 1.7 U/mL with 5% groundnut oil cake as an agricultural waste substrate. Activity and stability of the amylase were greatest at pH 7.0 and 45-55 °C. Na+, Ca2+, Mg2+, Co2+, Ba2+, and K+ increased activity, while Ni2+, Hg2+, Mn2+, Cu2+, Fe3+, and Zn2+ inhibited activity. EDTA, PMSF and DTNB reduced activity by 50% or more, while tetrafluoroethylene and 1,10-phenanthroline reduced activity by 30%. The amylase was highly tolerant of the surfactants, compatible with organic solvents, oxidizing agents and the reducing agents reduced activity. These properties suggest utility of amylase produced by B. subtilis B2 under blue LED-mediated fermentation for industrial applications.
Assuntos
Bacillus subtilis/metabolismo , Proteínas de Bactérias/metabolismo , Microbiologia Industrial/métodos , alfa-Amilases/metabolismo , Bacillus subtilis/química , Bacillus subtilis/efeitos da radiação , Proteínas de Bactérias/química , Cátions Bivalentes/metabolismo , Estabilidade Enzimática , Fermentação , Concentração de Íons de Hidrogênio , Luz , Metais/metabolismo , Temperatura , alfa-Amilases/químicaRESUMO
An exopolysaccharide (EPS)-producing heavy metal-resistant Gram-negative bacterium was isolated from ore-contaminated soil. The selected strain was identified by 16S rDNA sequencing and designated as Halomonas sp. MG. Phylogenetic analysis of the gene sequence showed its close similarity with Halomonas sp. Field emission scanning electron microscopy analysis revealed that the EPS had a porous structure with small pores. X-ray diffractograms showed the non-crystalline nature of the EPS. Further, FTIR spectroscopic analysis revealed the presence of carboxyl, hydroxyl and amide groups corresponding to a typical EPS.
Assuntos
Halomonas/classificação , Halomonas/isolamento & purificação , Polissacarídeos Bacterianos/metabolismo , Halomonas/efeitos dos fármacos , Halomonas/metabolismo , Metais Pesados/toxicidade , Microscopia Eletrônica de Varredura , Filogenia , Polissacarídeos Bacterianos/ultraestrutura , RNA Ribossômico 16S/genética , Especificidade da EspécieRESUMO
Phytoremediation is an in situ, low-cost strategy for cleanup of the sites contaminated with heavy metals. Experiments were conducted to assess the impact of synthetic chelators and plant growth-promoting rhizosphere bacteria (Herbaspirillum sp. GW103) on heavy metal lead (Pb) uptake in Z. mays cultivated in Pb-contaminated soil. The present study investigated the Pb phytoaccumulation rate and plant antioxidant enzyme activities in Z. mays exposed to 100 mg/kg of PbNO3. The combination of gluconic acid (GA) with Herbaspirillum sp. GW103 treatment showed higher Pb solubility (18.9 mg/kg) compared with other chelators. The chemical chelators showed the significant difference in phytoaccumulation as well as antioxidant enzyme activities. The antioxidant enzymes such as catalase, peroxidase and superoxide dismutase activities changed under Pb stress. The study indicated that increased activity of antioxidant enzymes may play as signal inducers to fight against Pb.
Assuntos
Antioxidantes/metabolismo , Quelantes/metabolismo , Herbaspirillum/metabolismo , Chumbo/metabolismo , Nitratos/metabolismo , Poluentes do Solo/metabolismo , Zea mays/metabolismo , Biodegradação Ambiental , Catalase/metabolismo , Gluconatos/metabolismo , Herbaspirillum/enzimologia , Estresse Oxidativo/fisiologia , Peroxidases/metabolismo , Rizosfera , Superóxido Dismutase/metabolismo , Zea mays/microbiologiaRESUMO
The accumulation of heavy metals such as lead (Pb), iron (Fe), zinc (Zn), cadmium (Cd), and chromium (Cr) was examined in crab (Scylla serrata) and shrimps (Penaeus semisulcatus, Penaeus indicus, and Penaeus monodon) collected from Pulicat lake that receives effluents from industries located in north Chennai, southeast coast of India. The results showed limited difference between crab and prawns as well as significant variations between the organs. Pb is the highly accumulated metal in both crab and shrimps, except P. monodon. The highest metal concentration was mostly found in the liver followed by other organs. The concentration of metals in edible parts (muscle) was within the permissible level and safe for consumption. However, the results of the study clearly indicate the biomagnification of metals in Pulicat lake.
Assuntos
Monitoramento Ambiental/métodos , Metais Pesados/análise , Frutos do Mar/análise , Poluentes Químicos da Água/análise , Animais , Braquiúros/química , Cádmio/análise , Cromo/análise , Contaminação de Alimentos/análise , Índia , Ferro/análise , Lagos , Chumbo/análise , Penaeidae/química , Zinco/análiseRESUMO
The aim of the study was to isolate and characterize potential multi-metal-resistant bacteria from ore soils. A total of three bacteria were isolated and assayed for resistance to arsenic (As), copper (Cu), and lead (Pb). Isolate Halomonas sp. MG exhibited maximum resistance to 1000 mg Pb/L, 800 mg As/L, and 500 mg Cu/L and it was identified as Halomonas sp. based on the partial 16S rDNA sequences. The metal(loid)s resistance mechanisms were further confirmed by amplification of arsC (As) copAU (Cu), and pbrT (Pb) genes. Biological transmission electron micrographs and XRD studies showed that the isolate Halomonas sp. MG transformed and/or biomineralized the metals either intracellularly or extracellularly. These results suggest that the isolate could be used as a potential candidate for the bioremediation of As, Cu, and Pb.
Assuntos
Adaptação Fisiológica , Halomonas/metabolismo , Magnésio/química , Metais Pesados/metabolismo , Solo/química , Adaptação Fisiológica/efeitos dos fármacos , Genes Bacterianos , Halomonas/classificação , Halomonas/efeitos dos fármacos , Halomonas/genética , Índia , Metais Pesados/farmacologia , Testes de Sensibilidade Microbiana , FilogeniaRESUMO
This study investigated the expression rate and molecular modeling of Wzb gene, a low molecular weight protein tyrosine phosphatase, under As stress in Herbaspirillum sp. GW103. Expression of Wzb gene was quantified at transcriptional level through real-time quantitative PCR. The results showed up- and down-regulations of Wzb gene in the presence of As (50 and 100 mg/L). The maximum Wzb transcript expression was 1.2-fold after 72 h exposure to 50 mg/L of As. However, the minimum expression was 0.1-fold after 48 h exposure to 100 mg/L of As. The Wzb protein sequence was retrieved from NCBI sequence database and was used for in silico analysis. 3D structure of Wzb gene was predicted by comparative modeling using modeler 9v9. Further, the model was validated for its quality by Ramachandran plot, ERRAT, Verify 3D, and SAVES server which revealed structure and quality of the Wzb gene model.
Assuntos
Arsênio/toxicidade , Perfilação da Expressão Gênica , Herbaspirillum/efeitos dos fármacos , Herbaspirillum/enzimologia , Proteínas Tirosina Fosfatases/biossíntese , Proteínas Tirosina Fosfatases/química , Modelos Moleculares , Conformação Proteica , Proteínas Tirosina Fosfatases/genética , Reação em Cadeia da Polimerase em Tempo Real , Transcrição GênicaRESUMO
Bacillus sp. strain JH 2-2, isolated from the rhizosphere of plants at a multi-metal contaminated mine site, has the potential to reduce Cr(VI) to Cr(III) and promote plant growth by reducing Cr toxicity and producing IAA. The minimum inhibitory concentration of Cr(VI) to Bacillus sp. JH 2-2 was 1000 mg L(-1) and the strain reduced 99% of 10 mg Cr(VI) L(-1) to Cr(IV) within 24 h. Lower Cr(VI) stress (10 mg L(-1) ) stimulated IAA production, but much less IAA was produced at 30 or 50 mg Cr(VI) L(-1) . Inoculation with Bacillus sp. JH 2-2 increased the length of Brassica juncea L. roots by 364% and stems by 735% in the presence of 10 mg Cr(VI) L(-1) from those of uninoculated control plants. These findings suggest potential use of Bacillus sp. JH 2-2 to promote phytoremediation of soil contaminated with Cr(VI).
Assuntos
Bacillus/metabolismo , Cromo/metabolismo , Ácidos Indolacéticos/metabolismo , Mostardeira/crescimento & desenvolvimento , Mostardeira/microbiologia , Reguladores de Crescimento de Plantas/metabolismo , Poluentes do Solo/metabolismo , Bacillus/efeitos dos fármacos , Biotransformação , Cromo/toxicidade , Testes de Sensibilidade Microbiana , Oxirredução , Desenvolvimento Vegetal , Raízes de Plantas/crescimento & desenvolvimento , Caules de Planta/crescimento & desenvolvimento , Poluentes do Solo/toxicidadeRESUMO
This study aimed to understand the influence of heavy metals on 1-aminocyclopropane-1-carboxylate deaminase activity (ACCD) and acdS gene expression in Herbaspirillium sp. GW103. The GW103 strain ACCD activity decreased in cells grown in a medium supplemented with Pb and As, whereas cells grown in medium supplemented with Cu showed increase in enzyme activity. The GW103 strain produced 262.2 ± 6.17 µmol of α-ketobutyrate per milligram of protein per hour during ACC deamination at 25 °C after 24 h incubation. Using a PCR approach, an acdS coding-gene of 1.06 kbp was amplified in isolate GW103, showing 92% identity with Herbaspirillum seropedicae SmR1 acdS gene. Real time quantitative polymerase chain reaction results indicate that the acdS expression rate was increased (7.1-fold) in the presence of Cu, whereas it decreased (0.2- and 0.1-fold) in the presence of As and Pb.
Assuntos
Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Herbaspirillum/enzimologia , Herbaspirillum/genética , Metais Pesados/metabolismo , Microbiologia do Solo , Arsênio , Carbono-Carbono Liases/genética , Cobre , DNA Bacteriano/genética , Herbaspirillum/isolamento & purificação , Chumbo , Raízes de Plantas , Reação em Cadeia da Polimerase em Tempo Real , Rizosfera , Análise de Sequência de DNARESUMO
Endophytic bacteria have the potential to promote plant growth and heavy metal(loid) (HM) removal from contaminated soil. Pseudomonas koreensis AGB-1, isolated from roots of Miscanthus sinensis growing in mine-tailing soil, exhibited high tolerance to HMs and plant growth promoting traits. Transmission electron microscope (TEM) analysis revealed that AGB-1 sequestered HMs extracellularly and their accumulation was visible as dark metal complexes on bacterial surfaces and outside of the cells. DNA sequencing of HM resistance marker genes indicated high homology to the appropriate regions of the arsB, ACR3(1), aoxB, and bmtA determinants. Inoculating mining site soil with AGB-1 increased M. sinensis biomass by 54%, chlorophyll by 27%, and protein content by 28%. High superoxide dismutase and catalase activities, and the lower malondialdehyde content of plants growing in AGB-1-inoculated soil indicate reduced oxidative stress. Metal(loid) concentrations in roots and shoots of plants grown in inoculated soil were higher than those of the controls in pot trials with mine tailing soil. Results suggest that AGB-1 can be used in association with M. sinensis to promote phytostabilization and remediation of HM-contaminated sites.
Assuntos
Biodegradação Ambiental , Metais Pesados/química , Poaceae/metabolismo , Pseudomonas/metabolismo , Poluentes do Solo/química , Solo/química , Biomassa , Poluição Ambiental/análise , Metais/análise , Mineração , Desenvolvimento Vegetal , Raízes de Plantas/metabolismoRESUMO
We present a simple, eco-friendly synthesis of silver and gold nanoparticles using a natural polymer pine gum solution as the reducing and capping agent. The pine gum solution was combined with silver nitrate (AgNO3) or a chloroauric acid (HAuCl4) solution to produce silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs), respectively. The reaction process was simple; formation of the nanoparticles was achieved by autoclaving the silver and gold ions with the pine gum. UV-Vis spectra showed surface plasmon resonance (SPR) for silver and gold nanoparticles at 432 and 539 nm, respectively. The elemental forms of AgNPs and AuNPs were confirmed by energy-dispersive X-ray spectroscopy (EDX). Fourier transform infrared spectroscopy (FTIR) showed the biomolecules present in the pine gum, AgNPs, and AuNPs. Transmission electron microscopy (TEM) images showed the shape and size of AgNPs and AuNPs. The crystalline nature of synthesized AgNPs and AuNPs was confirmed by X-ray crystallography [X-ray diffraction (XRD)]. Application of synthesized AgNPs onto cotton fabrics and leather, in order to evaluate their antibacterial properties against odor- or skin infection-causing bacteria, is also discussed. Among the four tested bacteria, AgNP-coated cotton fabric and leather samples displayed excellent antibacterial activity against Brevibacterium linens.
Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Nanopartículas Metálicas/química , Odorantes/prevenção & controle , Prata/farmacologia , Dermatopatias Bacterianas/veterinária , Têxteis/microbiologia , Animais , Antibacterianos/síntese química , Antibacterianos/química , Odorantes/análise , Prata/química , Pele/microbiologia , Dermatopatias Bacterianas/microbiologia , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Têxteis/análiseRESUMO
This study highlights the ability of nitrate-reducing Bacillus subtilis EWP-46 cell-free extract used for preparation of silver nanoparticles (AgNPs) by reduction of silver ions into nano silver. The production of AgNPs was optimized with several parameters such as hydrogen ion concentration, temperature, silver ion (Ag(+) ion) and time. The maximum AgNPs production was achieved at pH 10.0, temperature 60 °C, 1.0 mM Ag(+) ion and 720 min. The UV-Vis spectrum showed surface plasmon resonance peak at 420 nm, energy-dispersive X-ray spectroscopy (SEM-EDX) spectra showed the presence of element silver in pure form. Atomic force microscopy (AFM) and transmission electron microscopy images illustrated the nanoparticle size, shape, and average particle size ranging from 10 to 20 nm. Fourier transform infrared spectroscopy provided the evidence for the presence of biomolecules responsible for the reduction of silver ion, and X-ray diffraction analysis confirmed that the obtained nanoparticles were in crystalline form. SDS-PAGE was performed to identify the proteins and its molecular mass in the purified nitrate reductase from the cell-free extract. In addition, the minimum inhibitory concentration and minimum bactericidal concentration of AgNPs were investigated against gram-negative (Pseudomonas fluorescens) and gram-positive (Staphylococcus aureus) bacteria.
Assuntos
Antibacterianos , Bacillus subtilis/química , Nanopartículas Metálicas/química , Pseudomonas fluorescens/crescimento & desenvolvimento , Prata , Staphylococcus aureus/crescimento & desenvolvimento , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/farmacologia , Sistema Livre de Células/química , Prata/química , Prata/farmacologiaRESUMO
In the present study, we synthesized silver and gold nanoparticles with a particle size of 10-20 nm, using Zingiber officinale root extract as a reducing and capping agent. Chloroauric acid (HAuCl4) and silver nitrate (AgNO3) were mixed with Z. officinale root extract for the production of silver (AgNPs) and gold nanoparticles (AuNPs). The surface plasmon absorbance spectra of AgNPs and AuNPs were observed at 436-531 nm, respectively. Optimum nanoparticle production was achieved at pH 8 and 9, 1 mM metal ion, a reaction temperature 50 °C and reaction time of 150-180 min for AgNPs and AuNPs, respectively. An energy-dispersive X-ray spectroscopy (SEM-EDS) study provides proof for the purity of AgNPs and AuNPs. Transmission electron microscopy images show the diameter of well-dispersed AgNPs (10-20 nm) and AuNPs (5-20 nm). The nanocrystalline phase of Ag and Au with FCC crystal structures have been confirmed by X-ray diffraction analysis. Fourier transform infrared spectroscopy analysis shows the respective peaks for the potential biomolecules in the ginger rhizome extract, which are responsible for the reduction in metal ions and synthesized AgNPs and AuNPs. In addition, the synthesized AgNPs showed a moderate antibacterial activity against bacterial food pathogens.