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1.
Biotechnol Appl Biochem ; 66(1): 60-67, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30303255

RESUMO

The industrial applications and prospects of microbial peroxidase are on the upwards trend, thus necessitating the search for sources with high turnaround time. Actinobacterial species have been a major source of peroxidase for the obvious reasons of having robust metabolite expression capabilities. However, other bacteria species have been underexplored for peroxidase production, hence the motivation for the investigation into the peroxidase production potential of Raoultella ornithinolytica OKOH-1 (KX640917). The bacteria expressed optimum specific peroxidase activity of 16.48 ± 0.89 U mg-1 , which is higher than those previously reported. The optimal fermentation conditions were pH 5 (3.44 ± 0.64 U mL-1 ), incubation temperature of 35 °C (5.25 ± 0.00 U mL-1 ), and agitation speed of 150 rpm (9.45 ± 2.57 U mL-1 ), with guaiacol and ammonium chloride as the best inducer and nitrogen supplement, respectively. On valorization of agrowastes as a sole carbon source for the secretion of peroxidase, sawdust gave the best peroxidase yield (15.21 ± 2.48 U mg-1 ) under solid-state fermentation. Also, a nonperoxide-dependent enzyme activity, which suggests probable laccase activity, was observed. The ability of the bacteria to utilize agrowastes is highly economical and as well a suitable waste management strategy. Consequently, R. ornithinolytica OKOH-1 is a promising industrial strain with dexterity for enhanced peroxidase production.


Assuntos
Proteínas de Bactérias/sangue , Enterobacteriaceae/enzimologia , Peroxidases/química , Águas Residuárias/química , Purificação da Água/métodos , Agricultura
2.
Molecules ; 24(23)2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31801244

RESUMO

In this present study, silver nanoparticles (Ag/AgCl NPs) were synthesized using an aqueous leaf extract of Oedera genistifolia as a reducing agent. The biosynthesized Ag/AgCl NPs was characterized by UV-visible spectrophotometry, transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). In addition, sequel to antibacterial assay, the cytotoxic effect of the phytofabricated Ag/AgCl NPs was assessed against the HeLa cell line (human cervix adenocarcinoma). The results of the characterization of the synthesized Ag/AgCl NPs indicate the successful synthesis using plant extract as a reducing agent, with UV-Vis spectra between 290-360 nm. TEM results showed that Ag/AgCl NPs was spherical in shape with an average size of 34.2 nm. EDX analysis revealed that the particles were predominantly composed of carbon, oxygen, chlorine, and silver, while FTIR identified major phytochemical compounds, which could be responsible for bio-reducing and capping potential. XRD analysis showed the crystallinity of Ag/AgCl NPs, with a face-centred cubic structure. The studied Ag/AgCl NPs had no cytotoxic effect on HeLa cells and exhibited antibacterial activity (minimum inhibitory concentration (MIC) 0.25-1 mg/mL; minimum bactericidal concentration (MBC) 2-16 mg/mL) against both the Gram-negative and Gram-positive bacteria investigated. Findings from this study suggest that this plant as a good candidate for producing new antibacterial drugs.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Asteraceae/química , Nanopartículas Metálicas/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Compostos de Prata/química , Prata/química , Células HeLa , Humanos , Nanopartículas Metálicas/ultraestrutura , Testes de Sensibilidade Microbiana , Compostos Fitoquímicos/química , Compostos Fitoquímicos/farmacologia , Folhas de Planta/química , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral
3.
Water Environ Res ; 87(4): 298-303, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26462073

RESUMO

The flocculating efficiency and physiochemical properties of purified bioflocculant produced by Halomonas sp. Okoh were investigated. Approximately 1.213 g/L of bioflocculant was recovered after fermentation under predetermined ambient conditions. Jar test experimentation revealed optimum bioflocculant concentration as 0.2 mg/mL with flocculation activity of 66.1%. The thermostable bioflocculant retained high flocculation activity after heat treatment at 100 °C for 30 minutes; flocculation activity of 74% was achieved. Chemical analysis showed that the bioflocculant was composed of sugar (26.5%), protein (2.64%), and uronic acid (13.3%). The Fourier infrared spectroscopy spectrum of the purified bioflocculant revealed the presence of hydroxyl and carboxylic functional groups. Thermogravimetric analyses showed a varied decomposition step, thus, an indication of varied composition. Scanning electron micrograph revealed the amorphous structure of the bioflocculant. These results suggest potential applicability of the bioflocculant produced by Halomonas sp. Okoh industrially.


Assuntos
Biopolímeros/biossíntese , Biopolímeros/química , Halomonas/metabolismo , Biopolímeros/isolamento & purificação , Fenômenos Químicos , Floculação , Concentração de Íons de Hidrogênio , Temperatura
4.
Int J Mol Sci ; 16(6): 12986-3003, 2015 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-26062133

RESUMO

A bioflocculant named MBF-UFH produced by a Bacillus species isolated from sediment samples of Algoa Bay of the Eastern Cape Province of South Africa was characterized. The bacterial identification was through 16S rDNA sequencing; nucleotide sequences were deposited in GenBank as Bacillus sp. AEMREG7 with Accession Number KP659187. The production of the bioflocculant was observed to be closely associated with cell growth. The bioflocculant had the highest flocculating activity of 83.2% after 72 h of cultivation, and approximately 1.6 g of purified MBF-UFH was recovered from 1 L of fermentation broth. Its chemical analyses indicated that it is a glycoprotein composed of polysaccharide (76%) and protein (14%). Fourier transform infrared spectroscopy (FTIR) revealed that it consisted of hydroxyl, amide, carboxyl and methoxyl as the functional moieties. Scanning electron microscopy (SEM) revealed the amorphous structure of MBF-UFH and flocculated kaolin clay particles. The maximum flocculating activity of 92.6% against kaolin clay suspension was achieved at 0.3 mg/mL over pH ranges of 3-11 with the peak flocculating rate at pH 8 in the presence of MgCl2. The bioflocculant retained high flocculating activity of 90% after heating at 100 °C for 1 h. MBF-UFH appears to have immense potential as an alternative to conventional chemical flocculants.


Assuntos
Bacillus/química , Proteínas de Bactérias/química , Glicoproteínas/química , Polissacarídeos Bacterianos/química , Bacillus/genética , Proteínas de Bactérias/biossíntese , Sequência de Bases , Floculação , Glicoproteínas/biossíntese , Caulim/química , Dados de Sequência Molecular , Polissacarídeos Bacterianos/biossíntese , RNA Ribossômico 16S/genética
5.
Molecules ; 20(3): 5239-59, 2015 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-25806549

RESUMO

A bioflocculant-producing bacteria, isolated from sediment samples of a marine environment in the Eastern Cape Province of South Africa demonstrated a flocculating activity above 60% for kaolin clay suspension. Analysis of the 16S ribosomal deoxyribonucleic acid (rDNA) nucleotide sequence of the isolate in the GenBank database showed 99% similarity to Bacillus toyonensis strain BCT-7112 and it was deposited in the GenBank as Bacillus toyonensis strain AEMREG6 with accession number KP406731. The bacteria produced a bioflocculant (REG-6) optimally in the presence of glucose and NH4NO3 as the sole carbon and nitrogen source, respectively, initial medium pH of 5 and Ca2+ as the cation of choice. Chemical analysis showed that purified REG-6 was a glycoprotein mainly composed of polysaccharide (77.8%) and protein (11.5%). It was thermally stable and had strong flocculating activity against kaolin suspension over a wide range of pH values (3-11) with a relatively low dosage requirement of 0.1 mg/mL in the presence of Mn2+. Fourier transform infrared spectroscopy (FTIR) revealed the presence of hydroxyl, carboxyl and amide groups preferred for flocculation. Scanning electron microscopy (SEM) revealed that bridging was the main flocculation mechanism of REG-6. The outstanding flocculating performance of REG-6 holds great potential to replace the hazardous chemical flocculants currently used in water treatment.


Assuntos
Bacillus/isolamento & purificação , Bacillus/metabolismo , Sedimentos Geológicos/microbiologia , Glicoproteínas/química , Glicoproteínas/metabolismo , Bacillus/classificação , Bacillus/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Carbono/metabolismo , Floculação , Microscopia Eletrônica de Varredura , Dados de Sequência Molecular , Nitratos/metabolismo , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , África do Sul
6.
BMC Biotechnol ; 13: 62, 2013 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-23915393

RESUMO

BACKGROUND: Bioflocculants effect the aggregation of suspended solutes in solutions thus, a viable alternative to inorganic poly-ionic and synthetic organic flocculants which are associated with deleterious health problems. Consequently, a consortium of two bacteria species were evaluated for optimized bioflocculant yield following the inadequacies of axenic cultures. RESULTS: 16S rDNA nucleotide sequencing and BLAST analysis of nucleotide sequences were used to identify the bacterial species, carbon and nitrogen sources optimally supporting bioflocculant production were assessed and the purified bioflocculant characterized. CONCLUSIONS: The mixed culture produced bioflocculant with high flocculating activity and an improved yield. The efficiency observed with jar test may imply industrial applicability.


Assuntos
Actinobacteria/metabolismo , Floculação , Methylobacterium/metabolismo , Técnicas Bacteriológicas , Técnicas de Cocultura , Meios de Cultura , Fermentação
7.
Environ Technol ; 34(17-20): 2671-9, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24527629

RESUMO

We reported earlier on the bioflocculant production potential of Halobacillus sp. Mvuyo, a marine bacteria isolated from Algoa Bay sediment samples. In this paper we report on the detailed characterization of the purified bioflocculant composed of polysaccharide and protein. The optimum dose of the purified bioflocculant for the clarification of 4 g l(-1) kaolin clay suspension was 0.2 mg ml(-1) at neutral pH. Scanning electron micrograph (SEM) revealed the bioflocculant to have an amorphous structure. The Fourier transform infrared (FTIR) spectrum exhibited the presence of hydroxyl, carboxyl and amino groups in its structure. The bioflocculant was thermostable with relative bioflocculant activity residue of 74.4% after heat treatment at 100 degrees C. Moreover thermogravimetric analysis (TGA) exhibited a degradation temperature (Td) of - 140 degrees C. The flocculation efficiency of the bioflocculant was 86.2% compared with 82.6%, 74.5% and 70.9% for polyethylimine, ferric chloride and alum, respectively. This bioflocculant has immense promise as a substitute to inorganic and synthetic flocculants in view of their hazard implications.


Assuntos
Proteínas de Bactérias/química , Halobacillus/química , Polissacarídeos Bacterianos/química , Proteínas de Bactérias/isolamento & purificação , Floculação , Caulim/química , Polissacarídeos Bacterianos/isolamento & purificação
8.
Int J Mol Sci ; 13(1): 1054-1065, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22312304

RESUMO

A bioflocculant-producing bacteria was isolated from Tyume River in the Eastern Cape Province, South Africa and identified by 16S rRNA gene nucleotide sequence to have 91% similarity to Arthrobacter sp. 5J12A, and the nucleotide sequence was deposited in GenBank as Arthrobacter sp. Raats (accession number HQ875723). The bacteria produced an extracellular bioflocculant when grown aerobically in a production medium containing glucose as sole carbon source and had an initial pH of 7.0. Influences of carbon, nitrogen and metal ions sources, as well as initial pH on flocculating activity were investigated. The bacteria optimally produced the bioflocullant when lactose and urea were used as sole sources of carbon and nitrogen respectively with flocculating activities of 75.4% and 83.4% respectively. Also, the bacteria produced the bioflocculant optimally when initial pH of the medium was 7.0 (flocculating activity 84%), and when Mg(2+) was used as cation (flocculating activity 77%). Composition analyses indicated the bioflocculant to be principally a glycoprotein made up of about 56% protein and 25% total carbohydrate.


Assuntos
Arthrobacter/metabolismo , Rios/microbiologia , Arthrobacter/genética , Arthrobacter/isolamento & purificação , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Carbono/metabolismo , Floculação , Água Doce/microbiologia , Concentração de Íons de Hidrogênio , Nitrogênio/metabolismo , Polissacarídeos/química , Polissacarídeos/metabolismo , RNA Ribossômico 16S/genética , África do Sul
9.
Int J Mol Sci ; 13(7): 8679-8695, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22942728

RESUMO

We evaluated bioflocculant production by a freshwater actinobacteria whose 16S rDNA nucleotide sequence was deposited in GenBank as Streptomyces sp. Gansen (accession number HQ537129). Optimum culture conditions for bioflocculant production were an initial medium pH of 6.8, incubation temperature of 30 °C, agitation speed of 160 rpm and an inoculum size of 2% (v/v) of cell density 1.5 × 10(8) cfu/mL. The carbon, nitrogen and cation sources for optimum bioflocculant production were glucose (89% flocculating activity), ammonium sulfate (76% flocculating activity) and MgCl(2). Bioflocculant pyrolysis showed three step decomposition indicative of three components while chemical analyses showed 78% carbohydrate and 22% protein (wt/wt). The mass ratio of neutral sugar, amino sugar and uronic acids was 4.6:2.4:3. FTIR spectrometry indicated the presence of carboxyl, hydroxyl and amino groups, typical for heteropolysaccharide. The bioflocculant showed a lattice structure as seen by SEM imaging. Its high flocculation activity suggests its suitability for industrial applicability.


Assuntos
Proteínas de Bactérias/metabolismo , Glicoproteínas/metabolismo , Rios/microbiologia , Streptomyces , Microbiologia da Água , Proteínas de Bactérias/genética , Sequência de Bases , Glicoproteínas/genética , Dados de Sequência Molecular , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Streptomyces/genética , Streptomyces/isolamento & purificação , Streptomyces/metabolismo
10.
Environ Technol ; 33(7-9): 967-73, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22720422

RESUMO

A bioflocculant-producing bacteria isolated from marine sediment of Algoa Bay was assessed for its bioflocculant-producing potentials. Based on 16S recombinant deoxyribonucleic acid (rDNA) sequence analysis, the isolate was identified as Halobacillus sp. and deposited in the Genbank as Halobacillus sp. Mvuyo with accession number HQ537125. The bacteria produced bioflocculant optimally in the presence of glucose (76% flocculating activity) and ammonium chloride (93% flocculating activity) as sole sources of carbon and nitrogen, respectively. The flocculating capabilities of the flocculant were increased by the addition of Ca2+ (76% flocculating activity) and the highest flocculating activity was observed at neutral pH (7.0). The chemical analysis of the bioflocculant revealed that it contained mainly polysaccharide and protein.


Assuntos
Sedimentos Geológicos/microbiologia , Halobacillus/fisiologia , Floculação , Halobacillus/classificação , RNA Ribossômico 16S/genética , África do Sul
11.
Molecules ; 16(6): 4358-70, 2011 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-21613977

RESUMO

A bioflocculant-producing bacterium isolated from seawater was identified based on 16S rRNA gene nucleotide sequence to have 99% similarity to that of Halomonas sp. Au160H and the nucleotide sequence was deposited as Halomonas sp. OKOH (Genbank accession number is HQ875722). Influences of carbon source, nitrogen source, salt ions and pH on flocculating activity were investigated. The bioflocculant was optimally produced when glucose (87% flocculating activity) and urea (88% flocculating activity) were used as sources of carbon and nitrogen, respectively. Also, initial pH of 7.0 and Ca²âº supported optimal production of the bioflocculant with flocculating activities of 87% respectively. Chemical analyses revealed the bioflocculant to be a polysaccharide.


Assuntos
Sedimentos Geológicos/microbiologia , Halomonas/isolamento & purificação , Halomonas/metabolismo , Polissacarídeos/química , Polissacarídeos/metabolismo , Metabolismo dos Carboidratos , Cátions/metabolismo , Cátions/farmacologia , Floculação/efeitos dos fármacos , Halomonas/efeitos dos fármacos , Halomonas/genética , Concentração de Íons de Hidrogênio , Cinética , Nitrogênio/metabolismo , RNA Ribossômico 16S/genética
12.
Molecules ; 16(3): 2431-42, 2011 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-21403600

RESUMO

A bioflocculant-producing marine bacterium previously isolated from marine sediment of Algoa Bay was screened for flocculant production. Comparative analysis of 16S rDNA sequence identified the isolate to have 99% similarity to Virgibacillus sp. XQ-1 and it was deposited in the GenBank as Virgibacillus sp. Rob with accession number HQ537127. The bacterium produced biflocculants optimally in glucose (70.4%) and peptone (70.4%) as sole sources of carbon and nitrogen, alkaline pH (12) (74%); and the presence of Fe2+ (74%). Chemical analysis of the bioflocculant revealed it to be a polysaccharide.


Assuntos
Sedimentos Geológicos , Virgibacillus/metabolismo , Microbiologia da Água , Sequência de Bases , Primers do DNA , Floculação , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , África do Sul , Virgibacillus/genética , Virgibacillus/isolamento & purificação
13.
Int J Mol Sci ; 11(7): 2612-23, 2010 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-20717525

RESUMO

Crude extracts of three actinomycetes species belonging to Saccharopolyspora (TR 046 and TR 039) and Actinosynnema (TR 024) genera were screened for antibacterial activities against a panel of several bacterial strains. The extracts showed antibacterial activities against both gram-negative and gram-positive test bacteria with inhibition zones ranging from 8 to 28 mm (TR 046); 8 to15 mm (TR 039); and 10 to 13 mm (TR 024). The minimum inhibitory concentrations ranged from 0.078 to 10 mg/mL (TR 046); 5 to >10 mg/mL (TR 039); and 1.25 to 5 mg/mL (TR 024). Time-kill studies revealed that crude extract of TR 046 showed strong bactericidal activity against Bacillus pumilus (ATCC14884), reducing the bacterial load by 10(4) cfu/mL and 10(2) cfu/mL at 4x MIC and 2x MIC, respectively, after 6 h of exposure. Similarly, against Proteus vulgaris (CSIR 0030), crude extract of TR 046 achieved a 0.9log(10) and 0.13log(10) cfu/mL reduction at 5 mg/mL (4x MIC) and 1.25 mg/mL (2x MIC) after 12 h of exposure. The extract was however weakly bactericidal against two environmental bacterial strains (Klebsiella pneumoniae and Staphylococcus epidermidis); and against Pseudomonas aeruginosa (ATCC 19582): the extract showed bacteriostatic activities at all concentrations tested. These freshwater actinomycetes appear to have immense potential as a source of new antibacterial compound(s).


Assuntos
Actinobacteria/metabolismo , Antibacterianos/biossíntese , Antibacterianos/farmacologia , Água Doce/microbiologia , Testes de Sensibilidade Microbiana , África do Sul , Microbiologia da Água
14.
Saudi J Biol Sci ; 27(12): 3559-3569, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33304167

RESUMO

Boophone disticha (B. disticha) is a bulbous tropical and subtropical flowering plant widespread in Africa, which is frequently used to treat several human ailments. Until the present, there is no scientific validation on the biological activity of this plant from the Eastern Cape Province of South Africa and as a result, this study aimed to assess the bioactive compounds, free radicals scavenging and anticancer potentials of crude bulb extracts (chloroform, acetone, and ethanol) of Boophone disticha obtained from this geographical location. Standard biochemical techniques and Gas-chromatography mass spectrometry (GCMS) analysis were used to pinpoint the bioactive compounds in the crude extracts sequel to their antioxidant potentials against radicals such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), hydrogen peroxide and nitric oxide as well as their ferric ion reducing power. In addition, their cytotoxicity effects against Human cervix adenocarcinoma (HeLa) cells were assessed as an in vitro model for anticancer. The phytochemical evaluation of the crude extracts showed the presence of phenolics, flavonoids, and alkaloids. GCMS profiles confirmed the presence of some bioactive compounds in the crude extracts of B. disticha that could be responsible for their biological activities. The plant extracts possessed considerable antioxidant activity and exhibited dose-dependent radicals' inhibition from all assays carried out. Furthermore, the cytotoxicity effects against HeLa cells recorded inhibition concentration (IC50) of 1.5, 1.6, and 1.9 µg/mL for acetone, chloroform, and ethanolic extracts of B. disticha, respectively. Findings from the present study suggest that B. disticha could be a good prospective source of antioxidant and anticancer agents. Therefore, further research on the isolation and purification of compounds from these extracts are indispensable.

15.
3 Biotech ; 10(3): 141, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32206490

RESUMO

In the present study, we evaluated the phytochemical compounds and antioxidant properties of chloroform, ethanol and acetone extracts for leaves and flowers of Leonutus leonurus (L. leonurus) alongside with their cytotoxic effects on human cervical carcinoma (HeLa) cell lines. The phytochemical compounds present in the leaves and flowers of L. leonurus included; phenolics, flavonoids and alkaloids. Their radicals scavenging effects against 2, 2-diphenyl-1-picrylhydrazyl [DPPH] 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonate) [ABTS·+], hydrogen peroxide, nitric oxide as well as metal chelating activities showed dose-dependent activities. Gas chromatography-mass spectrometry (GCMS) analyses revealed the presence of important bioactive compounds, which are associated with antioxidant; and the extracts exhibited toxicity effect against HeLa cells. The findings from this study divulge extracts of L. leonurus as prospective sources of antioxidant and anticancer agents; and hence, further study on their neuroprotective potentials becomes imperative.

16.
Heliyon ; 5(12): e03012, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31890960

RESUMO

This study sought to determine the process conditions for optimum peroxidase production by a B acillus species (Bacillus sp. FALADE-1-KX640922) isolated from Hogsback forest reserve in South Africa and characterize the peroxidase gene in the bacteria. We optimized peroxidase production by manipulating the environmental and nutritional parameters under submerged fermentation. Subsequently, the gene encoding heme-peroxidase was determined through nested polymerase chain reaction and Sanger DNA sequencing. The studied bacteria had maximum peroxidase production at pH 8, 30 °C and 150 rpm. The addition of guaiacol to lignin fermentation medium enhanced peroxidase production by over 100 % in the studied bacteria. However, the other lignin monomers (veratryl alcohol, vanillin, vanillic acid and ferulic acid) repressed the enzyme activity. Modification of the fermentation medium with ammonium sulphate gave the maximum peroxidase yield (8.87 U mL-1). Under the predetermined culture conditions, Bacillus sp. FALADE-1 expressed maximum specific peroxidase activity at 48 h (8.32 U mg-1). Interestingly, a search of the sequenced gene in PeroxiBase showed 100% similarity to Sporotrichum thermophile catalase-peroxidase gene (katG), as well, the deduced protein sequence clustered with bacterial catalase-peroxidases and had a molecular weight of about 11.45 kDa with 7.01 as the estimated isoelectric point. Subsequently, the nucleotide sequence was deposited in the National Center for Biotechnology Information (NCBI) repository with the accession number MF407314. In conclusion, Bacillus sp. FALADE-1 is a promising candidate for improved peroxidase production.

17.
Int J Biol Macromol ; 121: 454-462, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30316770

RESUMO

The increase in industrial demand for peroxidases has necessitated the search for novel peroxidase with excellent industrial versatility. Raoultella ornithinolytica OKOH-1 is a new ligninolytic bacteria with peroxidase production potential. However, there is paucity of information on characterization of peroxidase from Raoultella species and its application potential in bioremediation. In this study, we characterized peroxidase from Raoultella ornithinolytica OKOH-1 (RaoPrx) for the first time using biochemical approach and bioinformatics; and as well investigated the dye-decolourization potential of the enzyme. RaoPrx oxidized various substrates, with pyrogallol giving the optimum activity. It had an optimum activity at pH 6 and was stable over a pH range of 5.0-7.0 with residual activity of above 40% after 120 min of incubation. The enzyme showed an optimum activity at 50 °C and was very stable at higher temperatures (50-70 °C) with residual activity of above 70% after 120 min. The enzyme was remarkably stable at 50 °C as it retained over 90% of its original activity after 120 min. The peroxidase activity was enhanced by Ag+, Cu2+, Zn2+and Fe2+, but was inhibited by Ca2+, Mg2+, Ba2+, Al3+, Co2+, NaN3 and EDTA. Furthermore, molecular characterization suggests RaoPrx as a novel dye-decolourizing peroxidase (DyP-type) family belonging to Class B, with estimated mo1ecular weight of 17.587 kDa and isoelectric point of 4.51, this is further confirmed by its remarkable dye-decolourizing activity on congo red and melanin in this study. This, therefore, indicates its application potential in textile dyes remediation and development of cosmetic agent.


Assuntos
Enterobacteriaceae/enzimologia , Peroxidase/metabolismo , Sequência de Bases , Cor , Inibidores Enzimáticos/farmacologia , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Metais/farmacologia , Peroxidase/antagonistas & inibidores , Peroxidase/química , Peroxidase/genética , Especificidade por Substrato , Temperatura
18.
Microbiologyopen ; 8(3): e00449, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30801981

RESUMO

In this study, we investigated the diversity of drug-resistant Mycobacterium tuberculosis isolates from families who own cattle in the Eastern Cape Province of South Africa using spoligotyping and mycobacterial interspersed repetitive-unit-variable number tandem repeat (MIRU-VNTR) typing. The Mycobacterium tuberculosis was investigated using MIRU-VNTR and the Mycobacterium tuberculosis families were evaluated using spoligotyping. Spoligotyping grouped 91% of the isolates into seven clusters, while 9% of the deoxyribonucleic acid (DNA) from TB isolates were unclustered from a total of 154 DNA used. Previously described shared types were observed in 89.6% of the isolates, with the Beijing family, SIT1, the principal genotype in the province, while the families T, SIT53 and X1, SIT1329 were the least detected genotypes. MIRU-VNTR grouped 81% of the isolates in 23 clusters while 19% were unclustered. A combination of the VNTR and spoligotyping grouped 79% of the isolates into 23 clusters with 21% unclustered. The low level of diversity and the clonal spread of drug-resistant Mycobacterium tuberculosis isolates advocate that the spread of TB in this study may be instigated by the clonal spread of Beijing genotype. The results from this study provide vital information about the lack of TB control and distribution of Mycobacterium tuberculosis complex strain types in the Eastern Cape Province of South Africa.


Assuntos
Genótipo , Tipagem Molecular , Mycobacterium tuberculosis/classificação , Mycobacterium tuberculosis/genética , Tuberculose Resistente a Múltiplos Medicamentos/epidemiologia , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia , Animais , Bovinos , Análise por Conglomerados , Características da Família , Saúde da Família , Epidemiologia Molecular , Mycobacterium tuberculosis/isolamento & purificação , África do Sul/epidemiologia
19.
Microbiologyopen ; 7(6): e00722, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30328673

RESUMO

Direct municipal wastewater effluent discharge from treatment plants has been identified as the major source of endocrine-disrupting chemicals (EDC) in freshwaters. Consequently, efficient elimination of EDC in wastewater is significant to good water quality. However, conventional wastewater treatment approaches have been deficient in the complete removal of these contaminants. Hence, the exploration of new and more efficient methods for elimination of EDC in wastewater is imperative. Enzymatic treatment approach has been suggested as a suitable option. Nonetheless, ligninolytic enzymes seem to be the most promising group of enzymes for EDC elimination, perhaps, owing to their unique catalytic properties and characteristic high redox potentials for oxidation of a wide spectrum of organic compounds. Therefore, this paper discusses the potential of some ligninolytic enzymes (laccase, manganese peroxidase, and versatile peroxidase) in the elimination of EDC in wastewater and proposes a new scheme of wastewater treatment process for EDC removal.


Assuntos
Disruptores Endócrinos/química , Lacase/química , Peroxidase/química , Peroxidases/química , Águas Residuárias/química , Poluentes Químicos da Água/química , Purificação da Água/métodos
20.
Biotechnol Rep (Amst) ; 16: 12-17, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29062721

RESUMO

Interest in novel ligninolytic bacteria has remained topical due to, in part, the maneuverability of the bacterial genome. Conversely, the fungal genome lacks the dexterity for similar maneuverability thus, posing challenges in the fungal enzyme yield optimization process. Some impact of this situation includes the inability to commercialize the bio-catalytic process of lignin degradation by fungi. Consequently, this study assessed some fresh water bacteria isolates for ligninolytic and peroxidase properties through the utilization and degradation of model lignin compounds (guaiacol and veratryl alcohol) and the decolourization of selected ligninolytic indicator dyes; Azure B (AZB), Remazol Brilliant Blue R (RBBR) and Congo Red (CR). Bacterial strains with appreciable ligninolytic and peroxidase production potentials were identified through 16S rDNA sequence analysis and the nucleotide sequences deposited in the GenBank. About 5 isolates were positive for the degradation of both guaiacol (GA) and veratryl alcohol (VA) thus, accounting for about 17% of the test isolates. Similarly, AZB, RBBR and CR were respectively decolorized by 3, 2 and 5 bacterial strains thus, accounting for 10%, 7% and 17% of the test isolates. Two of the test bacterial strains were able to decolourize AZB, RBBR and CR respectively and these bacterial strains were identified as Raoultella ornithinolytica OKOH-1 and Ensifer adhaerens NWODO-2 with respective accession numbers as KX640917 and KX640918. Upon quantitation of the peroxidase activities; 5250 ± 0.00 U/L was recorded against Raoultella ornithinolytica OKOH-1 and 5833 ± 0.00 U/L against Ensifer adhaerens NWODO-2. The ligninolytic and dye decolourization properties of Raoultella ornithinolytica OKOH-1 and Ensifer adhaerens NWODO-2 marks for novelty particularly, as dyes with arene substituents were decolourized. Consequently, the potentials for the industrial applicability of these test bacterial strains abound as there is a dearth of information on organisms with such potentials.

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