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1.
J Biomed Biotechnol ; 2012: 373682, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22536017

RESUMO

During the last years, several applications of biosurfactants with medical purposes have been reported. Biosurfactants are considered relevant molecules for applications in combating many diseases. However, their use is currently extremely limited due to their high cost in relation to that of chemical surfactants. Use of inexpensive substrates can drastically decrease its production cost. Here, twelve solid substrates were screened for the production of Bacillus subtilis SPB1 biosurfactant and the maximum yield was found with millet. A Plackett-Burman design was then used to evaluate the effects of five variables (temperature, moisture, initial pH, inoculum age, and inoculum size). Statistical analyses showed that temperature, inoculum age, and moisture content had significantly positive effect on SPB1 biosurfactant production. Their values were further optimized using a central composite design and a response surface methodology. The optimal conditions of temperature, inoculum age, and moisture content obtained under the conditions of study were 37°C, 14 h, and 88%, respectively. The evaluation of the antimicrobial activity of this compound was carried out against 11 bacteria and 8 fungi. The results demonstrated that this biosurfactant exhibited an important antimicrobial activity against microorganisms with multidrug-resistant profiles. Its activity was very effective against Staphylococcus aureus, Staphylococcus xylosus, Enterococcus faecalis, Klebsiella pneumonia, and so forth.


Assuntos
Anti-Infecciosos/metabolismo , Bacillus subtilis/metabolismo , Biotecnologia/métodos , Tensoativos/metabolismo , Análise de Variância , Anti-Infecciosos/análise , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Bacillus subtilis/crescimento & desenvolvimento , Bactérias/efeitos dos fármacos , Fermentação , Concentração de Íons de Hidrogênio , Cinética , Testes de Sensibilidade Microbiana , Filogenia , Reprodutibilidade dos Testes , Tensoativos/química , Tensoativos/farmacologia , Temperatura , Água
2.
Environ Sci Pollut Res Int ; 23(2): 1742-54, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26396008

RESUMO

Aeromonas veronii GRI (KF964486), isolated from acclimated textile effluent after selective enrichment on azo dye, was assessed for methyl orange biodegradation potency. Results suggested the potential of this bacterium for use in effective treatment of azo-dye-contaminated wastewaters under static conditions at neutral and alkaline pH value, characteristic of typical textile effluents. The strain could tolerate higher doses of dyes as it was able to decolorize up to 1000 mg/l. When used as microbial surfactant to enhance methyl orange biodecolorization, Bacillus subtilis SPB1-derived lipopeptide accelerated the decolorization rate and maximized slightly the decolorization efficiency at an optimal concentration of about 0.025%. In order to enhance the process efficiency, a Taguchi design was conducted. Phytotoxicity bioassay using sesame and radish seeds were carried out to assess the biotreatment effectiveness. The bacterium was able to effectively decolorize the azo dye when inoculated with an initial optical density of about 0.5 with 0.25% sucrose, 0.125% yeast extract, 0.01% SPB1 biosurfactant, and when conducting an agitation phase of about 24 h after static incubation. Germination potency showed an increase toward the nonoptimized conditions indicating an improvement of the biotreatment. When comparing with synthetic surfactants, a drastic decrease and an inhibition of orange methyl decolorization were observed in the presence of CTAB and SDS. The nonionic surfactant Tween 80 had a positive effect on methyl orange biodecolorization. Also, studies ensured that methyl orange removal by this strain could be due to endocellular enzymatic activities. To conclude, the addition of SPB1 bioemulsifier reduced energy costs by reducing effective decolorization period, biosurfactant stimulated bacterial decolorization method may provide highly efficient, inexpensive, and time-saving procedure in treatment of textile effluents.


Assuntos
Aeromonas/metabolismo , Compostos Azo/metabolismo , Corantes/metabolismo , Recuperação e Remediação Ambiental/métodos , Poluentes Químicos da Água/metabolismo , Aeromonas/classificação , Aeromonas/genética , Aeromonas/isolamento & purificação , Biodegradação Ambiental , Polissorbatos/análise , Tensoativos/análise , Têxteis , Águas Residuárias/análise
3.
Biotechnol Res Int ; 2012: 795430, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22649736

RESUMO

Nutritional requirements can contribute considerably to the production cost and the bioprocess economics. Media optimisation using response surface methodology is one of the used methods to ameliorate the bioprocess economics. In the present study, biosurfactant production by Bacillus subtilis SPB1 was effectively enhanced by response surface methodology. A Plackett-Burman-based statistical screening procedure was adopted to determine the most important factor affecting lipopeptide production. Eleven variables are screened and results show that glucose, K(2)HPO(4), and urea concentrations influence the most biosurfactant production. A Central Composite Design was conducted to optimize the three selected factors. Statistical analyses of the data of model fitting were done by using NemrodW. Results show a maximum predicted biosurfactant concentration of 2.93 (±0.32) g/L when using 15 g/L glucose, 6 g/L urea, and 1 g/L K(2)HPO(4). The predicted value is approximately 1.65 much higher than the original production determined by the conventional one-factor-at-a-time optimization method.

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