Página 1 dos resultados de 390 itens digitais encontrados em 0.007 segundos

Produção e ação de biossurfactante produzido por bactérias em meios salinos contaminados por hidrocarbonetos aromáticos; Production and action of biosurfactant produced by bacteria in saline media contaminated with aromatic hydrocarbons

Souza, Ellen Cristina
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 21/08/2013 PT
Relevância na Pesquisa
37.6%
A contaminação da água e do solo por hidrocarbonetos aromáticos tem aumentado ao longo dos anos, devido ao seu uso nos mais diversos segmentos industriais. Hidrocarbonetos, tais como tolueno, são descritos como extremamente poluentes, tóxicos e potencialmente mutagénicos e carcinogénicos para os seres humanos. Os hidrocarbonetos são compostos lipófilicos difíceis de serem eliminados, contudo, estes aromáticos podem ser removidos de ambientes contaminados por meio de biorremediação utilizando bactérias produtoras de surfactante. Biossurfatantes são surfactantes principalmente produzidos por microrganismos, as quais promovem a quebra das moléculas de hidrocarbonetos, através da formação de micelas, aumentando a sua mobilidade, a biodisponibilidade e sua exposição à bactérias favorecendo a biodegradação do hidrocarboneto. A produção deste tensoativo exige meios de fermentação e oxigênio para o metabolismo microbiano. Por tanto, aeração e agitação são variáveis operacionais importantes para garantir um coeficiente de transferência de massa de oxigénio eficaz (kLa). Para esta finalidade, o kLa foi determinado experimentalmente em diferentes meios de fermentação, especificamente meio salino básico...

Biosurfactant synthesis by Pseudomonas aeruginosa LBI isolated from a hydrocarbon-contaminated site

Pirollo, M. P. S.; Mariano, A. P.; Lovaglio, R. B.; Costa, S. G. V. A. O.; Walter, V.; Hausmann, R.; Contiero, Jonas
Fonte: Blackwell Publishing Publicador: Blackwell Publishing
Tipo: Artigo de Revista Científica Formato: 1484-1490
ENG
Relevância na Pesquisa
37.75%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Aims: Pseudomonas aeruginosa LBI (Industrial Biotechnology Laboratory) was isolated from hydrocarbon-contaminated soil as a potential producer of biosurfactant and evaluated for hydrocarbon biodegradation. The emulsifying power and stability of the product was assessed in the laboratory, simulating water contamination with benzene, toluene, kerosene, diesel oil and crude oil at various concentrations.Methods and Results: Bacteria were grown at 30 degrees C and shaken at 200 rpm for 168 h, with three repetitions. Surface tension, pH and biosurfactant stability were observed in the cell-free broth after 168 h of incubation. The strain was able to produce biosurfactant and grow in all the carbon sources under study, except benzene and toluene. When cultivated in 30% (w/v) diesel oil, the strain produced the highest quantities (9.9 g l(-1)) of biosurfactant. The biosurfactant was capable of emulsifying all the hydrocarbons tested.Conclusion: The results from the present study demonstrate that Ps. aeruginosa LBI can grow in diesel oil, kerosene, crude oil and oil sludge and the biosurfactant produced has potential applications in the bioremediation of hydrocarbon-contaminated sites.Significance and Impact of the Study: Pseudomonas aeruginosa LBI or the biosurfactant it produces can be used in the bioremediation of environmental pollution induced by industrial discharge or accidental hydrocarbon spills.

Use of weathered diesel oil as a low-cost raw material for biosurfactant production

Mariano, A. P.; Bonotto, Daniel Marcos; Angelis, D. F.; Pirôllo, M. P. S.; Contiero, Jonas
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: 269-274
ENG
Relevância na Pesquisa
37.6%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); This work aimed to investigate the capability of biosurfactant production by Staphylococcus hominis, Kocuria palustris and Pseudomonas aeruginosa LBI, using weathered diesel oil from a long-standing spillage as raw material. The effect of the culture media (Robert or Bushnell-Haas) and of the carbon source (spilled diesel oil or commercial diesel oil) on biosurfactant production was evaluated. Erlenmeyer flasks (250 mL) containing the cell broth were agitated (240 rpm) for 144 h at 27±2ºC. Biosurfactant production was monitored according to the de Nöuy ring method using a Krüss K6 tensiometer. Considering the possibility of intracellular storage of biosurfactant in the cell wall of the cultures S. hominis and K. palustris, experiments were also done applying ultrasound as a way to rupture the cells. For the conditions studied, the cultures did not indicate production of biosurfactants. Results obtained with a hydrocarbon biodegradability test based on the redox indicator 2,6-dichlorophenol indophenol showed that only the commercial diesel was biodegraded by the cultures.

Estudo da produção de biossurfactante pela bacteria Kocuria rhizophila.; Study of the biosurfactant production by Kocuria bacterium.

Beatriz Torsani Ubeda
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 30/04/2004 PT
Relevância na Pesquisa
37.71%
Biossurfactantes são agentes de superfície ativa sintetizados por várias espécies de microrganismos sendo as bactérias e as leveduras os principais produtores. A molécula do biossurfactante é formada por uma parte hidrofílica, solúvel em água, e uma parte hidrofóbica, solúvel em solvente orgânico. Tal composto é sintetizado durante o crescimento ou na fase estacionária do desenvolvimento do microrganismo em meios de cultura contendo hidrocarbonetos ou açúcares como fonte de carbono. A produção pode ser espontânea ou induzida através da presença de compostos lipídicos, por variações de pH, temperatura, aeração e agitação ou ainda, quando o crescimento celular é mantido sob condições de stress como baixas concentrações de nitrogênio e alterações nas condições ótimas de pH e temperatura. O processo de produção do biossurfactante contribui para a degradação de compostos hidrofóbicos, podendo ser empregado, no tratamento de águas residuárias e em solos contaminados por derramamento de petróleo e seus derivados, pois a célula microbiana busca a assimilação do hidrocarboneto como forma de obtenção de energia. Existe vasta possibilidade de aplicação em alimentos, na agricultura, na indústria cosmética e farmacêutica...

Estudo da recuperação, concentração e purificação de biossurfactante produzido por Bacillus subtilis; Study of recovery, concentration and purification process in a Bacillus subtilis biosurfactant

Mario Cezar Rodrigues Mano
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 13/02/2008 PT
Relevância na Pesquisa
37.79%
Biossurfactantes são compostos anfifílicos produzidos por microrganismos que possuem atividade superficial, ou seja, a capacidade de reduzir a tensão superficial e interfacial entre dois líquidos imiscíveis. Devido a suas características, esses compostos possuem uma ampla gama de potenciais utilizações que vão desde a indústria de alimentos, cosméticos, farmacêutica, petroquímica entre outras. O processo de recuperação e purificação de biossurfactantes é alvo de constantes aperfeiçoamentos, pois compreende, em alguns casos, até 60% do custo de produção dos mesmos. Alguns processos utilizados com mais freqüência para recuperação de biossurfactantes são as técnicas de fracionamento de espuma, precipitação e extração, além da ultrafiltração. O objetivo deste trabalho foi avaliar a viabilidade dos processos de ultrafiltração e diafiltração para recuperação e purificação de biossurfactantes produzidos por Bacillus subtilis. O processo foi conduzido com a produção de espuma via fermentação, que continha alta concentração de biossurfactantes. Após pré-tratamento, a espuma passou pelos processos de ultrafiltração e diafiltração, com parâmetros fixos e pré-estabelecidos. Os resultados da ultrafiltração mostram um aumento na concentração de biossurfactantes de 0...

Kinetic study of fermentative biosurfactant production by Lactobacillus strains

Rodrigues, L. R.; Moldes, Ana; Teixeira, J. A.; Oliveira, Rosário
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /02/2006 ENG
Relevância na Pesquisa
37.84%
Screening of biosurfactant-producing ability of four Lactobacillus strains was performed, being shown that for all the tested strains biosurfactant production occurred mainly in the first 4 h. The Lactobacillus strains showed zones of clearing in the blood agar with a diameter <1 cm. The minimum surface tension value of the fermentation broth achieved was 39.5 mN/m for Lactobacillus pentosus CECT-4023 that represents a reduction in the surface tension of 10.5 mN/m comparing with the control. Time courses of glucose, biomass and biosurfactant were modeled according to reported models. Using MRS broth (Man, Rogosa & Sharpe medium for lactobacilli strains) as culture medium, the values estimated by the modeling of biosurfactant were Pmax = 1.6 g of biosurfactant/L and rp/X = 0.091 g/(L h), for Lactobacillus casei CECT-5275, Pmax = 1.7 g/L and rp/X = 0.217 g/(L h) for Lactobacillus rhamnosus CECT-288, Pmax = 1.7 g/L and rp/X = 0.069 g/(L h) for L. pentosus CECT-4023 and Pmax = 1.8 g/L and rp/X = 0.090 g/(L h) for Lactobacillus coryniformis subsp. torquens CECT-25600. Pmax is the maximum concentration of biosurfactant (g/L), and Pr is the ratio between the initial volumetric rate of product formation (rp) and the initial product concentration P0 (g/L). Using whey as production medium...

Low-cost fermentative medium for biosurfactant production by probiotic bacteria

Rodrigues, L. R.; Teixeira, J. A.; Oliveira, Rosário
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /12/2006 ENG
Relevância na Pesquisa
37.66%
Potential use of alternative fermentative medium for biosurfactant production by Lactococcus lactis 53 and Streptococcus thermophilus A was studied. Suitable models were established to describe the response of the experiments pertaining to glucose, lactose or sucrose consumption, cell growth and biosurfactant production. Synthetic media MRS and M17 broth were used as control experiments. When the synthetic media were replaced by cheaper alternative media, as cheese whey and molasses, fermentations were carried out effectively with high yields and productivities of biosurfactant. An increase about 1.2–1.5 times in the mass of produced biosurfactant per gram cell dry weight and 60–80% medium preparation costs reduction were achieved, for both strains. In conclusion, the results obtained showed that supplemented cheese whey and molasses media can be used as a relatively inexpensive and economical alternative to synthetic media for biosurfactant production by probiotic bacteria, thus an attractive alternative as many of the potential applications for biosurfactants depend on whether they can be produced economically.; Fundação para a Ciência e a Tecnologia (FCT)

Isolation and functional characterization of a biosurfactant produced by Lactobacillus paracasei

Gudiña, Eduardo J.; Teixeira, J. A.; Rodrigues, L. R.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /03/2010 ENG
Relevância na Pesquisa
37.71%
In this study, the crude biosurfactant produced by a Lactobacillus paracasei strain isolated in a Portuguese dairy industry was characterized. The minimum surface tension (41.8mN/m) and the critical micelle concentration (2.5 mg/ml) obtained were found to be similar to the values previously reported for biosurfactants isolated from other lactobacilli. The biosurfactant was found to be stable to pH changes over a range from 6 to 10, being more effective at pH 7, and showed no loss of surface activity after incubation at 60 ◦C for 120 h. Although the biosurfactant chemical composition has not been determined yet, a fraction was isolated through acidic precipitation, which exhibited higher surface activity as compared with the crude biosurfactant. Furthermore, this isolated biosurfactant showed antimicrobial and anti-adhesive activities against several pathogenic microorganisms. In addition, L. paracasei exhibited a strong autoaggregating phenotype, which was maintained after washing and resuspending the cells in PBS, meaning that this attribute must be related to cell surface components and not to excreted factors. The autoaggregation ability exhibited by this strain, together with the antimicrobial and anti-adhesive properties observed for this biosurfactant opens the possibility for its use as an effective probiotic strain.; Fundação para a Ciência e a Tecnologia (FCT)under the scope of the Project BIOSURFA: Biosurfactants application for microbial adhesion inhibition in medical devices.

Antimicrobial and antiadhesive properties of a biosurfactant isolated from Lactobacillus paracasei ssp. paracasei A20

Gudiña, Eduardo J.; Rocha, V.; Teixeira, J. A.; Rodrigues, L. R.
Fonte: The Society for Applied Microbiology Publicador: The Society for Applied Microbiology
Tipo: Artigo de Revista Científica
Publicado em /04/2010 ENG
Relevância na Pesquisa
37.66%
Aims: The aim of this study was to determine the antimicrobial and antiadhesive properties of a biosurfactant isolated from Lactobacillus paracasei ssp. paracasei A20 against several micro-organisms, including Gram-positive and Gram-negative bacteria, yeasts and filamentous fungi. Methods and Results: Antimicrobial and antiadhesive activities were determined using the microdilution method in 96-well culture plates. The biosurfactant showed antimicrobial activity against all the micro-organisms assayed, and for twelve of the eighteen micro-organisms (including the pathogenic Candida albicans, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus agalactiae), the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were achieved for biosurfactant concentrations between 25 and 50 mg ml−1. Furthermore, the biosurfactant showed antiadhesive activity against most of the micro-organisms evaluated. Conclusions: As far as we know, this is the first compilation of data on antimicrobial and antiadhesive activities of biosurfactants obtained from lactobacilli against such a broad group of micro-organisms. Although the antiadhesive activity of biosurfactants isolated from lactic acid bacteria has been widely reported...

Antimicrobial and anti-adhesive potential of a biosurfactant Rufisan produced by Candida lipolytica UCP 0988

Rufino, R. D.; Luna, J. M.; Sarrubbo, L. A.; Rodrigues, L. R.; Teixeira, J. A.; Takaki, G. M. Campos
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /05/2011 ENG
Relevância na Pesquisa
37.75%
In the last years, researches developed with biosurfactants for application in the medical area have been revealing the promising biological activities of these biomolecules. In this work the antimicrobial and anti-adhesive properties of a biosurfactant Rufisan isolated from the yeast Candida lipolytica UCP 0988, growth in a medium supplemented with ground nut refinery residue was determined against several microorganisms. The biosurfactant was able to reduce the water surface tension from 70 to 25.3mN/m and showed a critical micelle concentration (CMC) of 0.03%. The biosurfactant was isolated after 72 h of fermentation and was tested in concentrations varying from 0.75 to 12 mg/l. The highest antimicrobial activities were observed against Streptococcus agalactiae, Streptococcus mutans, Streptococcus mutans NS, Streptococcus mutans HG, Streptococcus sanguis 12, Streptococcus oralis J22 at a concentration superior to the biosurfactant critical micelle concentration. Moreover, the biosurfactant showed anti-adhesive activity against most of the microorganisms tested. As far as we know, this is the first compilation of data on antimicrobial and anti-adhesive activities of a biosurfactant obtained from a Candida strain against such a broad group of microorganisms. The results obtained in this work showed that the biosurfactant from C. lipolytica is a potential antimicrobial and/or anti-adhesive agent for several biomedical applications; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco (FACEPE)

Production of biosurfactant by hydrocarbon degrading Rhodococcus ruber and Rhodococcus erythropolis

Bicca,Flávio Correa; Fleck,Leonardo Colombo; Ayub,Marco Antônio Záchia
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/1999 EN
Relevância na Pesquisa
37.6%
There is world wide concern about the liberation of hydrocarbons in the environment, both from industrial activities and from accidental spills of oil and oilrelated compounds. Biosurfactants, which are natural emulsifiers of hydrocarbons, are produced by some bacteria, fungi and yeast. They are polymers, totally or partially extracellular, with an amphipathyc structure, which allows them to form micelles that accumulate at the interface between liquids of different polarities such as water and oil. This process is based upon the ability of biosurfactants to reduce surface tension, blocking the formation of hydrogen bridges and certain hydrophilic and hydrophobic interactions. The ability of biosurfactant production by five strains of Rhodococcus isolated from oil prospecting sites was evaluated. Surface tension measurement and emulsifying index were used to quantify biosurfactant production. The influence of environmental conditions was also investigated - pH, temperature, medium composition, and type of carbon source - on cell growth and biosurfactant production. Strain AC 239 was shown to be a potential producer, attaining 63% of emulsifying index for a Diesel-water binary system. It could be used, either directly on oil spills in contained environments...

Use of weathered diesel oil as a low-cost raw material for biosurfactant production

Mariano,A. P.; Bonotto,D. M.; Angelis,D. F.; Pirôllo,M. P. S.; Contiero,J.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2008 EN
Relevância na Pesquisa
37.6%
This work aimed to investigate the capability of biosurfactant production by Staphylococcus hominis, Kocuria palustris and Pseudomonas aeruginosa LBI, using weathered diesel oil from a long-standing spillage as raw material. The effect of the culture media (Robert or Bushnell-Haas) and of the carbon source (spilled diesel oil or commercial diesel oil) on biosurfactant production was evaluated. Erlenmeyer flasks (250 mL) containing the cell broth were agitated (240 rpm) for 144 h at 27±2ºC. Biosurfactant production was monitored according to the De Nöuy ring method using a Krüss K6 tensiometer. Considering the possibility of intracellular storage of biosurfactant in the cell wall of the cultures S. hominis and K. palustris, experiments were also done applying ultrasound as a way to rupture the cells. For the conditions studied, the cultures did not indicate production of biosurfactants. Results obtained with a hydrocarbon biodegradability test based on the redox indicator 2,6-dichlorophenol indophenol showed that only the commercial diesel was biodegraded by the cultures.

Renewable resources for biosurfactant production by yarrowia lipolytica

Fontes,G. C.; Ramos,N. M.; Amaral,P. F. F.; Nele,M.; Coelho,M. A. Z.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2012 EN
Relevância na Pesquisa
37.66%
In this work, the production of a biosurfactant synthesized by Yarrowia lipolytica using different renewable resources as carbon source was investigated. Crude glycerol, a biodiesel co-product, and clarified cashew apple juice (CCAJ), an agroindustrial residue, were applied as feedstocks for the microbial surfactant synthesis. The microorganism was able to grow and produce biosurfactant on CCAJ and crude glycerol, achieving maximum emulsification indexes of 68.0% and 70.2% and maximum variations in surface tension of 18.0 mN.m-1and 22.0 mN.m-1, respectively. Different organic solvents (acetone, ethyl acetate and chloroform - methanol) were tested for biosurfactant extraction. Maximum biosurfactant recovery was obtained with chloroform - methanol (1:1), reaching 6.9 g.L-1for experiments using CCAJ and 7.9 g.L-1for media containing crude glycerol as carbon source.The results herein obtained indicate that CCAJ and the co-product of biodiesel production are appropriate raw materials for biosurfactant production by Y. lipolytica.

Evaluation of emulsifier stability of biosurfactant produced by Saccharomyces lipolytica CCT-0913

Lima,Álvaro Silva; Alegre,Ranulfo Monte
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2009 EN
Relevância na Pesquisa
37.6%
Surface-active compounds of biological origin are widely used for many industries (cosmetic, food, petrochemical). The Saccharomyces lipolytica CCT-0913 was able to grow and produce a biosurfactant on 5% (v/v) diesel-oil at pH 5.0 and 32ºC. The cell-free broth emulsified and stabilized the oil-in-water emulsion through a first order kinetics. The results showed that the initial pH value and temperature influenced the emulsifier stability (ES), which was the time when oil was separated. The biosurfactant presented different stabilization properties for vegetable and mineral oil in water solution, despite the highest values of the ES occurring with vegetable oil. The biosurfactant presented smallest ES when compared to commercial surfactants; however, this biosurfactant was not purified.

Antimicrobial activity of a biosurfactant produced by Bacillus licheniformis strain M104 grown on whey

Gomaa,Eman Zakaria
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2013 EN
Relevância na Pesquisa
37.71%
The aim of the present study was to investigate the antimicrobial effect of the lipopeptide biosurfactants produced by Bacillus licheniformis strain M104 grown on whey. The biosurfactant was investigated for potential antimicrobial activity by using the disc-diffusion method against different Gram-positive bacteria {B subtilis, B. thuringiensis (two strains), B. cereus, Staphylococcus aureus (two strains) and Listeria monocytogenes)}, Gram-negative bacteria {(Pseudomonas aeruginosa, Escherichia coli (two strains), Salmonella typhimurium, Proteous vulgaris and Klebsiella pneumoniae) and a yeast (Candida albicans)}. The biosurfactant showed profoundly distinct antibacterial activity toward tested bacteria and displayed an antifungal activity against the tested yeast. Maximum antimicrobial activity of the biosurfactant was shown against S. aureus ATCC 25928. The biosurfactant had a broad inhibition effect on intracellular components of S. aureus ATCC 25928. The antimicrobial effect of lipopeptide biosurfactant produced by B. licheniformis strain M104 was time and concentration dependent. When biosurfactant was added to S. aureus medium in a concentration of (48 μg / ml), the maximum reduction of acid soluble phosphorous (53.06 %)...

Biosurfactant production by Rhodococcus erythropolis and its application to oil removal

Pacheco,Graziela Jardim; Ciapina,Elisa Mara Prioli; Gomes,Edelvio de Barros; Pereira Junior,Nei
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2010 EN
Relevância na Pesquisa
37.6%
The influence of different nutrients on biosurfactant production by Rhodococcus erythropolis was investigated. Increasing the concentration of phosphate buffer from 30 up through 150 mmol/L stimulated an increase in biosurfactant production, which reached a maximum concentration of 285 mg/L in shaken flasks. Statistical analysis showed that glycerol, NaNO3,MgSO4 and yeast extract had significant effects on production. The results were confirmed in a batchwise bioreactor, and semi-growth-associated production was detected. Reduction in the surface tension, which indicates the presence of biosurfactant, reached a value of 38 mN/m at the end of 35 hours. Use of the produced biosurfactant for washing crude oil-contaminated soil showed that 2 and 4 times the critical micellar concentration (CMC) were able to remove 97 and 99% of the oil, respectively, after 1 month of impregnation.

Lactobacillus acidophilus-derived biosurfactant effect on gtfB and gtfC expression level in Streptococcus mutans biofilm cells

Tahmourespour,Arezoo; Salehi,Rasoul; Kermanshahi,Rooha Kasra
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2011 EN
Relevância na Pesquisa
37.71%
Streptococcus mutans (S. mutans), harboring biofilm formation, considered as a main aetiological factor of dental caries. Gtf genes play an important role in S. mutans biofilm formation. The purpose of this study was to investigate the effect of Lactobacillus acidophilus-derived biosurfactant on S. mutans biofilm formation and gtfB/C expression level (S. mutans standard strain ATCC35668 and isolated S. mutans strain (22) from dental plaque). The Lactobacillus acidophilus (L. acidophilus) DSM 20079 was selected as a probiotic strain to produce biosurfactant. The FTIR analysis of its biosurfactant showed that it appears to have a protein-like component. Due to the release of such biosurfactants, L. acidophilus was able to interfere in the adhesion and biofilm formation of the S. mutans to glass slide. It also could make streptococcal chains shorter. Using realtime RT-PCR quantitation method made it clear that gtfB and gtfC gene expression were decreased in the presence of L. acidophilus-derived biosurfactant fraction. Several properties of S. mutans cells (the surface properties, biofilm formation, adhesion ability and gene expression) were changed after L. acidophilus-derived biosurfactant treatment. It is also concluded that biosurfacant treatment can provide an optional way to control biofilm development. On the basis of our findings...

Scale up and application of biosurfactant from bacillus subtilis in enhanced oil recovery

Amani, H.; Mehrnia, M.; Sarrafzadeh, M.; Haghighi, M.; Soudi, M.
Fonte: Humana Press Inc Publicador: Humana Press Inc
Tipo: Artigo de Revista Científica
Publicado em //2010 EN
Relevância na Pesquisa
37.75%
There is a lack of fundamental knowledge about the scale up of biosurfactant production. In order to develop suitable technology of commercialization, carrying out tests in shake flasks and bioreactors was essential. A reactor with integrated foam collector was designed for biosurfactant production using Bacillus subtilis isolated from agricultural soil. The yield of biosurfactant on biomass (Y(p/x)), biosurfactant on sucrose (Y(p/s)), and the volumetric production rate (Y) for shake flask were obtained about 0.45 g g(-1), 0.18 g g(-1), and 0.03 g l(-1) h(-1), respectively. The best condition for bioreactor was 300 rpm and 1.5 vvm, giving Y(x/s), Y(p/x), Y(p/s), and Y of 0.42 g g(-1), 0.595 g g(-1), 0.25 g g(-1), and 0.057 g l(-1) h(-1), respectively. The biosurfactant maximum production, 2.5 g l(-1), was reached in 44 h of growth, which was 28% better than the shake flask. The obtained volumetric oxygen transfer coefficient (K(L)a) values at optimum conditions in the shake flask and the bioreactor were found to be around 0.01 and 0.0117 s(-1), respectively. Comparison of K(L)a values at optimum conditions shows that biosurfactant production scaling up from shake flask to bioreactor can be done with K(L) a as scale up criterion very accurately. Nearly 8% of original oil in place was recovered using this biosurfactant after water flooding in the sand pack.; Hossein Amani...

Comparative study of biosurfactant producing bacteria in MEOR applications

Amani, H.; Sarrafzadeh, M.; Haghighi, M.; Mehrnia, M.
Fonte: Elsevier Science BV Publicador: Elsevier Science BV
Tipo: Artigo de Revista Científica
Publicado em //2010 EN
Relevância na Pesquisa
37.75%
In this work, biosurfactant production by Bacillus subtilis, Pseudomonas aeruginosa, and Bacillus cereus has been compared. These microorganisms were isolated from agricultural and oil polluted area of Iran. Maximum biosurfactant production reached to about 1.6 g/l and liquid surface tension decreased from 72 to 25 mN/m using B. subtilis. All screened bacteria exhibited a good ability to emulsify the crude oil. Biosurfactant of B. subtilis attained an emulsion index of 75% for crude oil which was significantly greater than other strains. Stability studies were carried out under the extreme environmental conditions as find normally in the oil reservoir such as high temperature, pH and salinity. Results showed an excellent resistance of all produced biosurfactants to retain their surface-active properties at extreme conditions. It was found that the biosurfactants show a good stability around pH of 4 but at lower pH, they will harmfully be affected. Lesser precipitation has been observed at low pH for biosurfactant produced by B. subtilis. It has also been observed that biosurfactants from three isolated bacteria were able to support the condition up to 25 g/l salinity. B. cereus biosurfactant was even stable at the higher salinity. Regarding temperature...

Antimicrobial and anti-adhesive activities of cell-bound biosurfactant from Lactobacillus agilis CCUG31450

Gudiña, Eduardo J.; Fernandes, E.; Teixeira, J. A.; Rodrigues, L. R.
Fonte: The Royal Society of Chemistry Publicador: The Royal Society of Chemistry
Tipo: Artigo de Revista Científica
Publicado em 16/10/2015 ENG
Relevância na Pesquisa
37.79%
In this work, biosurfactant production by different Lactobacillus strains was studied using the conventional MRS medium for lactic acid bacteria. Lactobacillus agilis CCUG31450 produced a cell-bound biosurfactant that reduced the surface tension of water to 42.5 mN/m, and exhibited a high emulsifying activity (E24=60%). The amount of biosurfactant produced was 84 mg/l, with a cmc of 7.5 mg/ml. A preliminary chemical characterization by Fourier Transform Infrared Spectroscopy indicated that the biosurfactant is a glycoprotein. Using cheese whey as an alternative culture medium, biosurfactant production was increased up to 960 mg/l. The biosurfactant exhibited a considerable anti-adhesive activity against Staphylococcus aureus, as well as antimicrobial activity against S. aureus, Streptococcus agalactiae and Pseudomonas aeruginosa. This study represents the first description of a biosurfactant produced by a L. agilis strain. The results obtained open future prospects for the application of this biosurfactant to reduce or inhibit the adhesion of pathogenic microorganisms (such as S. aureus) in several biomedical applications.