RESUMEN

Background The effects of exposure to copper, during growth, on the production of biomass, total protein, catalase, glutathione-S transferase, glutathione peroxidase, peroxidase, polyphosphate, acid and alkaline phosphatases, ultrastructure and the ability to remove this metal from Aspergillus niger, obtained from caatinga soil, were evaluated. Results All parameters tested were influenced by the concentration of metal in the culture medium. The presence of metal induced high levels of antioxidant enzymes, including lipid peroxidation, thereby revealing the appearance of an oxidative stress response. The variation in polyphosphate levels indicates the participation of the polymer in response to stress induced by copper. The activities of the phosphatases were positively influenced by growing them in the presence of copper. Ultrastructure changes in the cell surface, electron density, thickness, and septation were visualized by exposing cells to increasingly larger concentrations of metal. The isolate was able to remove the agent from the growth medium, while maintaining its physiological functions. The metal removed from the cultures exposed to 0.5 mM, 1 mM and 2 mM copper exhibited percentages of removal equivalent to 75.78%, 66.04% and 33.51%. Conclusions The results indicate that the isolate was able to grow in high concentrations of copper, activates mechanisms for adaptation and tolerance in the presence of metal, and is highly efficient at removing the agent. Such data are fundamental if a better understanding is to be reached of the cellular and molecular abilities of native isolates, which can be used to develop bioprocesses in environmental and industrial areas.

Asunto(s)

Aspergillus niger/enzimología , Aspergillus niger/fisiología , Adaptación Biológica , Estrés Oxidativo , Cobre/química , Polifosfatos , Microscopía Electrónica de Rastreo , Peroxidación de Lípido , Enzimas , Antioxidantes

RESUMEN

A Mucoralean fungus was isolated from Caatinga soil of Pernambuco, Northeast of Brazil, and was identified as Cunninghamella echinulata by morphological, physiological, and biochemical tests. This strain was evaluated for biosurfactant/bioemulsifier production using soybean oil waste (SOW) and corn steep liquor (CSL) as substrates, added to basic saline solution, by measuring surface tension and emulsifier index and activity. The best results showed the surface water tension was reduced from 72 to 36 mN/m, and an emulsification index (E24) of 80% was obtained using engine oil and burnt engine oil, respectively. A new molecule of biosurfactant showed an anionic charge and a polymeric chemical composition consisting of lipids (40.0% w/w), carbohydrates (35.2% w/w) and protein (20.3% w/w). In addition, the biosurfactant solution (1%) demonstrated its ability for an oil displacement area (ODA) of 37.36 cm², which is quite similar to that for Triton X-100 (38.46 cm²). The stability of the reduction in the surface water tension as well as of the emulsifier index proved to be stable over a wide range of temperatures, in pH, and in salt concentration (4%-6% w/v). The biosurfactant showed an ability to reduce and increase the viscosity of hydrophobic substrates and their molecules, suggesting that it is a suitable candidate for mediated enhanced oil recovery. At the same time, these studies indicate that renewable, relatively inexpensive and easily available resources can be used for important biotechnological processes.

Asunto(s)

Cunninghamella/química , Emulsionantes/aislamiento & purificación , Tensoactivos/aislamiento & purificación , Biodegradación Ambiental , Brasil , Carbohidratos/análisis , Carbono/metabolismo , Cunninghamella/crecimiento & desarrollo , Cunninghamella/aislamiento & purificación , Cunninghamella/metabolismo , Estabilidad de Medicamentos , Emulsionantes/química , Aceites Combustibles , Proteínas Fúngicas/análisis , Concentración de Iones de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Residuos Industriales , Lípidos/análisis , Micelas , Nitrógeno/metabolismo , Salinidad , Microbiología del Suelo , Glycine max , Tensión Superficial/efectos de los fármacos , Tensoactivos/química , Temperatura , Viscosidad , Agua , Zea mays

RESUMEN

Studies were carried out with Cunninghamella elegans UCP/WFCC 0542 to evaluate the effects of an abundant supply of amino acids, asparagine and corn steep liquor associated with sucrose on the production of biomass and chitosan by submerged fermentation. The concentrations of the components of the culture medium which were determined by a 2³ full factorial design evaluated the interactions and effects of the independent variables of the sucrose, asparagine and corn steep liquor in relation to carbon and nitrogen sources, on the production of chitosan regarding biomass. The best results were observed at the central point [asparagine 0.025%, sucrose 0.15% and 0.45% of corn steep liquor, ratio C:N=2:6], and produced maximum yields of 16.95 g/L biomass and 2.14 g/L chitosan, after 96 h of submerged fermentation. However, the lowest level of sucrose, asparagine and corn steep liquor produced a low amount of biomass (10.83 g/L) and chitosan (0.60 g/L). The infrared spectrum absorption of the chitosan produced by C. elegans showed bands regarding OH-axial stretching between 3406 and 3432 cm⁻¹, superimposed on the NH stretching band with axial deformation of the amide C=O group at about 1639 cm⁻¹, NH angular deformation at approximately 1560 cm⁻¹; axial deformation of amide-CN at around 1421 cm⁻¹, symmetrical angular deformation in CH3 at 1379 cm⁻¹, -CN axial deformation of amino groups from 1125 to 1250 cm⁻¹ and polysaccharide structure bands in the range of between 890-1150 cm⁻¹. The crystallinity index of chitosan was 60.92%, and its degree of deacetylation was 75.25%. A low percentage of a supply of sucrose and asparagine with corn steep liquor offered higher yields of biomass and chitosan production at low cost.

Asunto(s)

Aminoácidos/metabolismo , Quitosano/metabolismo , Cunninghamella/metabolismo , Asparagina/metabolismo , Biomasa , Quitosano/química , Quitosano/aislamiento & purificación , Medios de Cultivo , Cunninghamella/crecimiento & desarrollo , Fermentación , Polisacáridos Fúngicos/química , Polisacáridos Fúngicos/aislamiento & purificación , Polisacáridos Fúngicos/metabolismo , Sacarosa/metabolismo , Difracción de Rayos X

RESUMEN

The biosorption of three reactive azo dyes (red, black and orange II) found in textile effluents by inactive mycelium of Cunninghamella elegans has been investigated. It was found that after 120 hours of contact the adsorption led to 70%, 85%, 93% and 88% removal of reactive orange II, reactive black, reactive red and a mixture of them, respectively. The mycelium surface was found to be selective towards the azo dyes in the following order: reactive red > reactive black > orange II. Dye removal from a mixture solution resulted in 48.4 mg/g retention by mycelium and indicated a competition amongst the dyes for the cellular surface. A Freundlich adsorption isotherm model exhibited a better fit, thus suggesting the presence of heterogeneous binding sites. Electrondense deposits observed on the mycelium ultrastructure suggest that the dyes are mainly retained under the cellular surface of the inactive biomass of C. elegans.

Asunto(s)

Compuestos Azo/aislamiento & purificación , Biodegradación Ambiental , Colorantes/aislamiento & purificación , Cunninghamella/química , Micelio/química , Adsorción , Algoritmos , Compuestos Azo/química , Colorantes/química , Cunninghamella/ultraestructura , Cinética , Viabilidad Microbiana , Microscopía Electrónica de Transmisión , Modelos Químicos , Micelio/ultraestructura , Espectrofotometría Ultravioleta , Industria Textil

RESUMEN

The physiological mutant of Rhizopus arrhizus was obtained in the pyrene resistance gradient test. Comparative studies were carried out about the behavior of the germination process and the radial growth of the mutant and wild strains of R. arrhizus UCP 402. Sabouraud Sucrose and Yeast Malt Broth cultures containing pyrene (10 mg/L) induced the germination process of the sporangiospores of the wild and mutant strains of R. arrhizus. The radial growth of the strains was inversely proportional to the pyrene concentration in the culture medium. The results showed an adaptation of R. arrhizus UCP 402x (mutant) in the pyrene (50mg/L) and suggested a higher ability of application in the removal of pyrene from the contaminated areas.

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O mutante fisiológico de Rhizopus arrhizus foi obtido pelo teste do gradiente de resistência ao pireno. Estudos comparativos conduzidos sobre o comportamento do processo de germinação e o crescimento radial foram realizados entre as amostras selvagem e mutante de R. arrhizus UCP 402. Os meios Sabouraud Sacarose e Caldo de Levedura e Malte contendo pireno (10 mg/L) induziram ao processo de germinação de esporangiosporos das amostras selvagem e mutante de R. arrhizus. O crescimento radial das amostras foi inversamente proporcional à concentração de pireno no meio de cultura. Os resultados demonstraram uma excelente adaptação da amostra mutante de R. arrhizus UCP 402x na concentração de pireno (50 mg/L), sugerindo uma alta habilidade e possibilidade de aplicação na remoção de pireno em áreas contaminadas.

RESUMEN

The fungi are characterized by their abilities to produce and secrete enzymes to the external environment. The species of genus Mucor are a group of fungal microbes with important biotechnological potential, which are responsible for production of industrial enzymes. This work evaluated the ability of protease production in twelve species of genus Mucor. The strains were kept for 120 h under the incubation temperature of 28 degrees C on a shaker at 120 rpm. The detection of proteolytic activity was evaluated in all species, the higher activity was detected in Mucor racemosus Fres. f. chibinensis (Neophytova) Schipper.

Asunto(s)

Proteínas Fúngicas/análisis , Mucor/enzimología , Péptido Hidrolasas/análisis , Medios de Cultivo , Líquido Extracelular/enzimología , Fermentación , Concentración de Iones de Hidrógeno , Mucor/clasificación

RESUMEN

En el presente trabajo se analizaron las proteínas de la pared celular de 2 cepas de paracoccidioides brasiliensis en fase levaduriforme (PbHC-PE y Pb 18). Las proteínas fueron extraidas por tres difrentes métodos y estudiadas por electroféresis SDS-PAGE. Los resultados de los perfiles de las dos cepas fueron diferentes, permitiendo la posibilidad de su uso como marcadores quimiotaxonómicos. Se observó una secreción transitoria de la proteína gp 43 a través de la pared celular de las cepas de p. brasiliensis.

Asunto(s)

Pared Celular/ultraestructura , Paracoccidioides/citología , Proteínas Fúngicas/análisis , Proteínas Fúngicas/aislamiento & purificación