RESUMO
Abstract Various chemical compounds, including surfactants, when introduced to culture media may increase the permeability of cellular membranes and thereby affect the quantity of metabolites excreted by cells. The aim of the present study was to evaluate the impact of detergents including Triton X-100, Span 20 and Tween 80 on erythritol production from glycerol by Yarrowia lipolytica Wratislavia K1 in a shake-flask experiment, batch and fed-batch cultures. When Span 20 was added to a fed-batch culture with glycerol as a carbon source (300 g L-1), erythritol production increased by 15% compared to the culture without the surfactant where it reached 142 g L-1 after 5 days, which corresponded to 0.47 g g-1 yield and productivity of 1.1 g L-1 h-1. Therefore, it was concluded that Span 20 considerably enhanced the production of this polyol from glycerol.
Assuntos
Tensoativos/metabolismo , Meios de Cultura/metabolismo , Yarrowia/metabolismo , Eritritol/biossíntese , Manitol/metabolismo , Polissorbatos/análise , Polissorbatos/metabolismo , Tensoativos/análise , Octoxinol/análise , Octoxinol/metabolismo , Meios de Cultura/química , Eritritol/análise , Manitol/análiseRESUMO
Various chemical compounds, including surfactants, when introduced to culture media may increase the permeability of cellular membranes and thereby affect the quantity of metabolites excreted by cells. The aim of the present study was to evaluate the impact of detergents including Triton X-100, Span 20 and Tween 80 on erythritol production from glycerol by Yarrowia lipolytica Wratislavia K1 in a shake-flask experiment, batch and fed-batch cultures. When Span 20 was added to a fed-batch culture with glycerol as a carbon source (300gL(-1)), erythritol production increased by 15% compared to the culture without the surfactant where it reached 142gL(-1) after 5 days, which corresponded to 0.47gg(-1) yield and productivity of 1.1gL(-1)h(-1). Therefore, it was concluded that Span 20 considerably enhanced the production of this polyol from glycerol.
Assuntos
Meios de Cultura/metabolismo , Eritritol/biossíntese , Manitol/metabolismo , Tensoativos/metabolismo , Yarrowia/metabolismo , Meios de Cultura/química , Eritritol/análise , Manitol/análise , Octoxinol/análise , Octoxinol/metabolismo , Polissorbatos/análise , Polissorbatos/metabolismo , Tensoativos/análiseRESUMO
Lactobacillus sakei subsp. sakei 2a is a bacteriocinogenic lactic acid bacterium isolated from Brazilian pork sausage, capable of inhibiting the growth of microbial pathogens, mainly Listeria monocytogenes. In order to optimize bacteriocin production for industrial applications, this study evaluated the effect of supplementation of MRS broth with glucose, Tween 20, Tween 80, sodium citrate, potassium chloride and cysteine, and effect of the initial pH and temperature of incubation of the medium on production of bacteriocins by L. sakei 2a. Adding glucose and Tween 20 to the medium, an initial pH of 5.0 or 5.5, and incubation temperatures of 25 °C or 30 °C resulted to the highest bacteriocin yields. Thus, a 2(4) factorial design with the four variables was performed, and statistical analysis showed that it was an adequate model (R (2) = 0.8296). In the studied range, the four parameters significantly influenced bacteriocin production, with the maximum yield produced at an initial pH between 5.5 and 7.0, a temperature between 25 and 30 °C and supplementation of the MRS broth with glucose from 3.25 to 6.0 g L(-1) and Tween 20 from 0.575 to 1.15% (v/v). Response Surface Methodology analysis indicated that the highest bacteriocin production (12800 AU mL(-1)) occurred in the MRS broth supplemented with 5.5 g L(-1) glucose and 1.05% Tween 20 at an initial pH of 6.28 and an incubation temperature of 25 °C. The amount of bacteriocin produced in commercial MRS broths under the same conditions was only 5600AU mL(-1).
Assuntos
Antibacterianos/metabolismo , Bacteriocinas/metabolismo , Meios de Cultura/metabolismo , Lactobacillus/crescimento & desenvolvimento , Lactobacillus/metabolismo , Brasil , Glucose/metabolismo , Lactobacillus/classificação , Testes de Sensibilidade Microbiana , Polissorbatos/metabolismo , Carne Vermelha/microbiologia , Propriedades de Superfície , TemperaturaRESUMO
Assuntos
Antibacterianos/metabolismo , Bacteriocinas/metabolismo , Meios de Cultura/metabolismo , Lactobacillus/crescimento & desenvolvimento , Lactobacillus/metabolismo , Brasil , Glucose/metabolismo , Lactobacillus/classificação , Testes de Sensibilidade Microbiana , Polissorbatos/metabolismo , Carne Vermelha/microbiologia , Propriedades de Superfície , TemperaturaRESUMO
Assuntos
Antibacterianos/metabolismo , Bacteriocinas/metabolismo , Meios de Cultura/metabolismo , Lactobacillus/crescimento & desenvolvimento , Lactobacillus/metabolismo , Brasil , Glucose/metabolismo , Lactobacillus/classificação , Testes de Sensibilidade Microbiana , Polissorbatos/metabolismo , Carne Vermelha/microbiologia , Propriedades de Superfície , TemperaturaRESUMO
The large-scale production of nematophagous fungi as agents of biological control is one of the main challenges to be commercially used. In order to improve growth of microorganism in a culture medium, the addition of growth inducer is common. At the moment, the action of their addition in the mycelia growth and sporulation rate of nematophagous fungi is not known. The purpose of this trial was to evaluate the sporulation rate of Duddingtonia flagrans by adding two growth inducers, meso-inositol and Tween 80, both at 0.5 % in a traditional culture medium Sabouraud glucose agar (SGA) and also in a traditional culture medium enriched with wheat flour and milk powder. From a traditional sterile culture of D. flagrans, four groups were made: SGA; Sabouraud glucose agar-meso-inositol 0.5 %; Sabouraud glucose agar-Tween 80 0.5 %; and Sabouraud glucose agar-enriched (SGA-E). These media were placed at a constant temperature of 27 °C for 4 weeks. Following this, chlamydospores were gently rinsed off with sterile water and counted using a Neubauer haematocytometer to estimate the number of chlamydospores per millilitre of water. The addition of meso-inositol 0.5 % to SGA promoted a significant increase (p < 0.05) in chlamydospore production obtaining an average of 51,715,000 chlamydospores per Petri dish. The highest chlamydospore concentration was observed in the SGA-E in comparison with SGA (p < 0.01) obtaining an average of 208,760,000 chlamydospores. The aim of this study was to obtain basic knowledge regarding the effect of enriched culture medium and growth-inducing meso-inositol and Tween 80 on mycelial growth and production of chlamydospores.
Assuntos
Meios de Cultura/química , Duddingtonia/crescimento & desenvolvimento , Microbiologia Industrial/métodos , Esporos Fúngicos/crescimento & desenvolvimento , Glucose/metabolismo , Inositol/metabolismo , Polissorbatos/metabolismo , Temperatura , Fatores de TempoRESUMO
The aim of this study was to evaluate the effects of the 5.25% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), and MTAD solutions on the surface of gutta-percha and Resilon cones by using atomic force microscopy (AFM). Accessory cones were washed and dried. The cones were randomly divided into six groups: gutta-percha immersed in NaOCl, CHX, and MTAD, and Resilon immersed in NaOCl, CHX, and MTAD. AFM images of the same area were made in different periods of time. JPK™ Image Processing Software was used to evaluate the images. The parameters used to evaluate the changes were RMS and line profiles. No statistically significant change was observed in the RMS values. The line profiles detected changes only for gutta-percha surfaces after immersion in NaOCl and MTAD solutions. In conclusion, 5.25% NaOCl and MTAD are associated with local changes in surface roughness of gutta-percha cones. No change was observed when 2% CHX was used. The use of all tested solutions did not produce any changes on Resilon surface.
Assuntos
Clorexidina/química , Ácido Cítrico/química , Desinfetantes/química , Doxiciclina/química , Guta-Percha/química , Polissorbatos/química , Materiais Restauradores do Canal Radicular/química , Hipoclorito de Sódio/química , Clorexidina/metabolismo , Ácido Cítrico/metabolismo , Desinfetantes/metabolismo , Doxiciclina/metabolismo , Guta-Percha/metabolismo , Microscopia de Força Atômica , Polissorbatos/metabolismo , Materiais Restauradores do Canal Radicular/metabolismo , Hipoclorito de Sódio/metabolismo , Soluções/química , Soluções/metabolismo , Propriedades de Superfície , Fatores de TempoRESUMO
This study aimed to correlate the efficiency of enzymatic hydrolysis of the cellulose contained in a sugarcane bagasse sample pretreated with dilute H(2)SO(4) with the levels of independent variables such as initial content of solids and loadings of enzymes and surfactant (Tween 20), for two cellulolytic commercial preparations. The preparations, designated cellulase I and cellulase II, were characterized regarding the activities of total cellulases, endoglucanase, cellobiohydrolase, cellobiase, ß-glucosidase, xylanase, and phenoloxidases (laccase, manganese and lignin peroxidases), as well as protein contents. Both extracts showed complete cellulolytic complexes and considerable activities of xylanases, without activities of phenoloxidases. For the enzymatic hydrolyses, two 2(3) central composite full factorial designs were employed to evaluate the effects caused by the initial content of solids (1.19-4.81%, w/w) and loadings of enzymes (1.9-38.1 FPU/g bagasse) and Tween 20 (0.0-0.1 g/g bagasse) on the cellulose digestibility. Within 24 h of enzymatic hydrolysis, all three independent variables influenced the conversion of cellulose by cellulase I. Using cellulase II, only enzyme and surfactant loadings showed significant effects on cellulose conversion. An additional experiment demonstrated the possibility of increasing the initial content of solids to values much higher than 4.81% (w/w) without compromising the efficiency of cellulose conversion, consequently improving the glucose concentration in the hydrolysate.
Assuntos
Celulases/metabolismo , Celulose/metabolismo , Saccharum/metabolismo , Ácidos Sulfúricos/química , Celulase/metabolismo , Celulases/química , Celulose/química , Conservação de Recursos Energéticos , Conservação dos Recursos Naturais , Etanol/economia , Etanol/metabolismo , Hidrólise , Polissorbatos/metabolismo , Saccharum/química , beta-Glucosidase/metabolismoRESUMO
In order to detect intracellular antigens, cells must first be permeabilized especially after fixation with cross-linking agents such as formaldehyde and glutaraldehyde. Permeabilization provides access to intracellular or intraorganellar antigens. Two general types of reagents are commonly used: organic solvents, such as methanol and acetone, and detergents such as saponin, Triton X-100 and Tween-20. The organic solvents dissolve lipids from cell membranes making them permeable to antibodies. Because the organic solvents also coagulate proteins, they can be used to fix and permeabilize cells at the same time. Saponin interacts with membrane cholesterol, selectively removing it and leaving holes in the membrane. The disadvantage of detergents such as Triton X-100 and Tween-20 is that they are non-selective in nature and may extract proteins along with the lipids. This chapter provides methods for the use of organic solvents and detergents to permeabilize cell membranes.
Assuntos
Permeabilidade da Membrana Celular , Membrana Celular/metabolismo , Detergentes/metabolismo , Animais , Linhagem Celular , Humanos , Octoxinol/metabolismo , Polissorbatos/metabolismo , Saponinas/metabolismoRESUMO
Surfactants, particularly non-ionic types, are often added to prevent and/or minimize protein aggregation during fermentation, purification, freeze-drying, shipping, and/or storage. In this work we have investigated the interactions between two non-ionic surfactants (Tween 20 and Tween 80) and bovine serum albumin (BSA), as model protein, using surface tension, fluorescence measurements and computational analysis. The results showed that, in both cases, the surface tension profile of the surfactants curve is modified upon addition of the protein, and the CMC values of Tween 20 and Tween 80 in the presence of protein are higher than the CMC values of the pure surfactants. The results indicate that although Tween 20 and Tween 80 do not greatly differ in their chemical structures, their interactions with BSA are of different nature, with distinct binding sites. Measurements at different protein concentrations showed that the interactions are also dependent on the protein aggregation state in solution. It was found from fluorescence studies that changes observed in both the intensity and wavelength of the tryptophan emission are probably caused by modifications of tryptophan environment due to surfactant binding, rather than by direct interaction. Based on a computational analysis of a BSA three-dimensional model, we hypothesize about the binding mechanism of non-ionic surfactant to globular protein, which allowed us to explain surface tension profiles and fluorescence results.