Evaluation of Moringa oleifera Seed Lectin as a Metal Remover in Aqueous Solutions.

The efficacy of Moringa oleifera seed lectin (WSMoL) as a metal remover in water and the effects of metals on its hemagglutinating and antibacterial activities were determined. Aqueous metal solutions were incubated with WSMoL for 8 h at 4°C and the concentrations of metals were determined using atomic absorption spectroscopy. Hemagglutination and antibacterial assays were conducted with WSMoL and lectin exposed or not to the metals. The removal efficiency of WSMoL was 49.00%, 53.21%, 71.45%, 55.42%, 69.88%, 62.14%, and 49.36% for Cd+2, Pb+2, Cu+2, Zn+2, Mg+2, Mn+2, and Al+3, respectively. WSMoL showed bacteriostatic and bactericidal activities against Escherichia coli and Salmonella enterica serovar Enteritidis. However, hemagglutinating and antibacterial activities were impaired after exposure to metals. In conclusion, WSMoL efficiently removed metals present in water but the interaction with metals impaired lectin carbohydrate-binding ability and antibacterial activity. This should be considered when properties of WSMoL other than metal removal are desired.

Enhancement of Cunninghamella elegans UCP/WFCC 0542 biomass and chitosan with amino acid supply.

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.

Cadmium tolerance and removal from Cunninghamella elegans related to the polyphosphate metabolism.

The aim of the present work was to study the cadmium effects on growth, ultrastructure and polyphosphate metabolism, as well as to evaluate the metal removal and accumulation by Cunninghamella elegans (IFM 46109) growing in culture medium. The presence of cadmium reduced growth, and a longer lag phase was observed. However, the phosphate uptake from the culture medium increased 15% when compared to the control. Moreover, C. elegans removed 70%-81% of the cadmium added to the culture medium during its growth. The C. elegans mycelia showed a removal efficiency of 280 mg/g at a cadmium concentration of 22.10 mg/L, and the removal velocity of cadmium was 0.107 mg/h. Additionally, it was observed that cadmium induced vacuolization, the presence of electron dense deposits in vacuoles, cytoplasm and cell membranes, as well as the distinct behavior of polyphosphate fractions. The results obtained with C. elegans suggest that precipitation, vacuolization and polyphosphate fractions were associated to cadmium tolerance, and this species demonstrated a higher potential for bioremediation of heavy metals.

A biosorption isotherm model for the removal of reactive azo dyes by inactivated mycelia of Cunninghamella elegans UCP542.

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.

A cytochemical study of acid carbohydrates on the surface of Candida lipolytica grown in tween 80-containing medium

Carbohydrate-containing molecules were located on the surface of Candida lipolytica by using ruthenium red in a cytochemical study. The yeast was grown in media containing Tween 80. The surfactant, at 1.0 (per cent) and 0.5 (per cent), was added to the culture medium in different intervals of time, correspondent to the beginning of exponential growth phase, mid of logarithimic phase and beginning of stationary growth phase. Control cultures were grown in a medium containing glucose. The growth of the yeast in media containing glucose and Tween 80 induced changes in the pattern of distribution and location of acid polyssacharides in the cell wall of the microorganism. In adition, the pattern also changed according to Tween 80 concentration. The influence of Tween 80 on cellular carbohydrate expression is discussed.

Actin cytoskeleton structure and its localization in gongronella butleri, mucor javanicus and absidia cylindrospora (mucorales-zygomycetes)

Mediante estudios de microscopia òptica de fluorescencia se describe y caracteriza la estructura, distribución y localización de la actina, en tres especies de hongos de la clase zygomycetes: absidia cylindrospora, gongronella butleri y mucor javanicus. La estructura de la actina fué analizada utilizándose el marcador fitc-phalloidina, especifico para actina, en muestras fijadas con formaldehido. En los resultados se observan diferencias en la estructura, distribución y localización de esta proteina en las especies analizadas. Filamentos , aglomerados, placas o aglomerados periféricos y gránulos, fueron las formas más comunes encontradas en los hongos, con prevalencia de los aglomerados observados en todos los citoplasma de las hifas. La tinción de actina en losápices de las hifas, solo se observó en mucor javanicus, esta diferencia en la estructura de la actina podría estar asociada a zonas de expansión de la pared celular de los hongos

Effects of tween 80 on protease production by candida lipolytica

Se estudió la acción del tween 80, agente tensoactivo no iónico, sobre la proteasa producida por candida lipolytica. El microorganismo fue cultivado en medio de cultivo conteniendo diferentes concentraciones del agente, el cual fue introducido en el medio en diferentes intervalos de tiempo. La presencia del agente en el medio de cultivo incrementó la actividad de la proteasa extracelular e intracelular y el crecimiento del hongo. Los efectos del agente podrían estar relacionados con el tiempo de adición y las concentraciones empleadas en el medio de cultivo

Effects of sodium dodecyl sulfate on the growth of Candida lipolytica

Neste trabalho o efeito do dodecil sulfato de sódio sobre o crescimento de Candida lipolytica foi analisado. O surfactante foi adicionado ao meio de cultura, nas concentraçöes de 0,07 por cento, 0,09 por cento e 0,11 por cento nas diferentes fases de crescimento celular 0.8, 16 e 24 h. As culturas foram crescidas por 96 h a 27ºC e o crescimento foi acompanhado pela contagem de células viáveis, velocidade máxima de crescimento e tempo de geraçäo. A inibiçäo do crescimento pode ser relacionada ao tempo de adiçäo do composto após 24 h de cultivo näo demonstrou qualquer efeito sobre o microrganismo