Symbiotic potential and survival of native rhizobia kept on different carriers

Native rhizobia are ideal for use as commercial legume inoculants. The characteristics of the carrier used to store the inoculants are important for the survival and symbiotic potential of the rhizobia. The objective of this study was to investigate the effects of peat (PEAT), perlite sugarcane bagasse (PSB), carboxymethyl cellulose plus starch (CMCS), and yeast extract mannitol supplemented with mannitol (YEMM) on the survival, nodulation potential and N₂ fixation capacity of the native strains Sinorhizobium mexicanum ITTG R7^T and Rhizobium calliandrae LBP2-1^T and of the reference strain Rhizobium etli CFN42^T. A factorial design (4 × 3) with four repetitions was used to determine the symbiotic potential of the rhizobial strains. The survival of the strains was higher for PEAT (46% for strain LBP2-1^T, 167% for strain CFN42^T and 219% for strain ITTG R7^T) than for the other carriers after 240 days, except for CFN42^T kept on CMCS (225%). All the strains kept on the different carriers effectively nodulated common bean, with the lowest number of nodules found (5 nodules) when CFN42^T was kept on CMCS and with the highest number of nodules found (28 nodules) when ITTG R7^T was kept on PSB. The nitrogenase activity was the highest for ITTG R7^T kept on PEAT (4911 μmol C₂H₄ per fresh weight nodule h⁻¹); however, no activity was found when the strains were kept on YEMM. Thus, the survival and symbiotic potential of the rhizobia depended on the carrier used to store them.

Statistical medium optimization of an alkaline protease from Pseudomonas aeruginosa MTCC 10501, its characterization and application in leather processing.

Proteases are shown to have greener mode of application in leather processing for dehairing of goat skins and cow hides. Production of protease by submerged fermentation with potent activity is reported using a new isolate P. aeruginosa MTCC 10501. The production parameters were optimized by statistical methods such as Plackett-Burman and response surface methodology. The optimized production medium contained (g/L); tryptone, 2.5; yeast extract, 3.0; skim milk 30.0; dextrose 1.0; inoculum concentration 4%: initial pH 6.0; incubation temperature 30 °C and optimum production at 48 h with protease activity of 7.6 U/mL. The protease had the following characteristics: pH optima, 9.0; temperature optima 50 °C; pH stability between 5.0-10.0 and temperature stability between 10-40 °C. The protease was observed to have high potential for dehairing of goat skins in the pre- tanning process comparable to that of the chemical process as evidenced by histology. The method offers cleaner processing using enzyme only instead of toxic chemicals in the pre-tanning process of leather manufacture.

[ effect of yeast supplementation on the growth and immune system in rainbow trout [Oncorhynchus mykiss]]

Today, uses of natural substances are preferred to chemical and synthetic compounds for growth and immune enhancement of aquatic organisms. The aim of this research was to evaluate the effect of Saccharomyces cerevisiae extract and hydrolyzed powder on growth parameters and resistance of rainbow trout against temperature and hypoxia stresses with a bacterial challenge. For this purpose six hundred rainbow trout [50 +/- 5 g mean weight] were purchased from a local fish farm and transferred to the laboratory. After acclimatization to the laboratory conditions the fish were randomly divided into four groups each with triplicate. The first group was fed with a commercial diet [control] while the other groups received yeast extract, hydrolyzed powder and a mixture of them with the commercial diet. Fish were cultured in a 300 l polyethylene tank for 60 days and growth parameters were analyzed at days 0 and 60. Also, at the end of study the fish were challenged with hypoxia and temperature stresses with an experimental bacterial infection. Results showed that the extract and hydrolyzed powder of Saccharomyces cerevisiae in combination significantly [p=0.021] improved rainbow trout growth parameters compared with the control. The results also proved that fish survival significantly increased following feeding with a mixture of the extract and hydrolyzed powder after thermal [69.55 +/- 4.59], hypoxia [96.55 +/- 5.34] and yersiniosis [49.11 +/- 2.18] challenge than the control. Dietary administration of yeast extract with mixture of hydrolyzed powder of Saccharomyces cerevisiae could improve rainbow trout growth parameters and increase the resistance against stresses and disease

Caracterização química do autolisado de levedura de alambique e avaliação da aceitabilidade do pão de queijo adicionado do autolisado desidratado / Chemical characterization of yeast autolysate and assessment of the acceptability of cheese buns containing dried autolysate

OBJETIVO: Esta pesquisa tem como objetivo estudar as propriedades do autolisado de levedura (Saccharomyces cerevisiae) proveniente de cachaça de alambique, investigando a composição centesimal, o perfil acídico e a análise microbiológica do material, bem como realizar análise sensorial do pão de queijo adicionado com o autolisado desidratado. MÉTODOS: O autolisado foi obtido pela lavagem e autólise da biomassa. A secagem foi realizada em secador de bandeja na temperatura de 70ºC. Realizaram-se as seguintes análises: caracterização físico-química (teor lipídico, proteico, fibras totais, fibras solúveis e insolúveis, e cinzas); composição de aminoácidos; análises microbiológicas do produto desidratado; e avaliação sensorial do pão de queijo contendo o autolisado desidratado, através de escala hedônica e teste de atitude. RESULTADOS: O autolisado desidratado apresentou: 1,2 por cento de lipídeos; 24,7 por cento de proteínas; 51,3 por cento de fibras totais, sendo 2,4 por cento de fibras solúveis e 48,9 por cento de insolúveis; e 6,2 por cento de cinzas. As análises microbiológicas mostraram-se dentro do limite recomendado pela Agência Nacional de Vigilância Sanitária. O perfil aminoacídico mostrou deficiência de histidina e metionina+cistina. A análise sensorial do pão de queijo mostrou boa aceitação, tendo apenas cor e aparência recebido notas baixas. A maioria dos participantes disse que "gosta disto e compraria de vez em quando". CONCLUSÃO: Os valores de proteína e aminoácidos encontrados na levedura de cachaça de alambique foram inferiores ao mostrado na literatura para levedura de cervejaria e destilaria de álcool etílico. A levedura desidratada estava microbiologicamente apta para consumo humano. A baixa aceitabilidade da aparência do pão de queijo provavelmente ocorreu pelo fato de os consumidores não estarem habituados à cor escura do produto. Trabalhos futuros poderão sugerir adição em outros produtos que apresentem aparência mais atrativa.

OBJECTIVE: This study aimed to study the properties of yeast (Saccharomyces cerevisiae) autolysate obtained from pot still rum, including centesimal composition, amino acid profile and microbiological analysis, and perform a sensory analysis of cheese buns (also known as Brazilian cheese bread or rolls) enriched with dried autolysate. METHODS: Autolysate was obtained by rinsing and autolyzing the biomass and dried on a tray dryer at 70º. Its composition was then determined (fat, protein, total fiber, soluble fiber, insoluble fiber, ash and amino acid contents) followed by microbiological analysis. Finally, cheese buns enriched with dried autolysate were submitted to sensory analysis using the hedonic scale and attitude test. RESULTS: Dried autolysate contained 1.2 percent fats; 24.7 percent proteins; 51.3 percent total fiber, where 2.4 percent was soluble and 48.9 percent was insoluble; and 6.2 percent ash. According to microbiological analysis, the product complied with the microbiological limits established by the Agência Nacional de Vigilância Sanitária. Amino acid profile showed that histidine and methionine-cystine levels were low. Sensory analysis indicated good acceptance of the cheese buns. Only their color and appearance received low scores. Most participants reported liking the cheese buns and willingness to buy them on occasion. CONCLUSION: The protein and amino acid levels found in pot still rum were lower than those reported in the literature for breweries and ethanol distilleries. Dried yeast was microbiologically suitable for human consumption. The low grades given to the appearance of the cheese buns were probably due to their unappealing dark color, as opposed to the usual pale yellow color. Future studies could suggest the addition of dried yeast to products whose visual appeal will not be as affected.

Productividad y selectividad del medio de cultivo a partir de guayaba agria (psidium araca) en el crecimiento de levaduras nativas del género candida sp / Productivity and selectivity of culture medium from the sour guava (psidium araca) in the growth of native yeast candida sp

El presente trabajo se llevó a cabo para evaluar la eficiencia del medio de cultivo a partir de guayaba agria (Psidium araca) frente a medios comerciales en el crecimiento de tres cepas nativas: Candida guillermondii, Candida famita y Candida sp. Se evaluó el crecimiento microbiano a diferentes concentraciones de fruta, 5, 10, 25 y 50% p/v, tomando como control los medios comerciales: Malta, Sabouraud y agar papa dextrosa (PDA). La productividad y selectividad del medio de guayaba agria fue determinada mediante el método Ecométrico en un tiempo de 48 horas. Los análisis estadísticos aplicados para evaluar y comparar el crecimiento de las cepas en los medios comerciales y en el medio de guayaba agria a diferentes concentraciones demostraron lo siguiente: Candida guillermondii presentó crecimiento mayor o igual a 25 y 50% p/v comparado con los medios comerciales; Candida famata y Candida sp presentaron mejores crecimientos al 5% p/v, con respecto a los diferentes medios comerciales. Los resultados demostraron que el medio de cultivo es altamente productivo y no selectivo, lo que representa una alternativa en la conservación, el mantenimiento y el desarrollo de las levaduras estudiadas.

This work was carried out to evaluate the efficiency of the culture medium from sour guava (Psidium araca) against commercial media in the growth of three native strains: Candida guillermondii, Candida famata and Candida sp. Microbial growth was evaluated at different concentrations of fruit, 5, 10, 25, 50% w /v, using as control the commercial media: Malta, Sabouraud and PDA (Potato Dextrose Agar). The productivity and selectivity of the sour guava medium was determined by the Ecometric method in a time of 48 hours. The applied statistical analysis to evaluate and compare growth of strains in commercial culture medium and in the medium from sour guava at different concentrations showed: Candida guillermondii grew greater than or equal to 25 and 50% w / v compared with commercial medium, Candida famata and Candida sp showed better growth at 5% w / v, with respect to commercial medium. The results showed that the medium is highly productive and non-selective representing an alternative to the conservation, maintenance and development of the yeasts.

Anticancer and apoptosis-inducing activities of microbial metabolites

The problems of systemic toxicity and drug resistance in cancer chemotherapy urge the continuing discovery of new anticancer agents. We explored the specific anticancer activity from microbial metabolites to find new lead compound. 394 microbial extracts were evaluated on anti-proliferative activity against 4 cancer cell lines using MTT assay. Of these, 20 samples showed varying degree of cytotoxicity but specifically to the cancer cell lines since the growth of normal cells was not significantly inhibited by 1 mg/ml of each cell extracts. The 4 most potent extracts exhibited strongest growth inhibition to each cancer cell type were selected for further studied. Cell morphological changes such as cell shrinkage, lose of surface contact and blebbing were observed in all treated cancer cells. DNA-binding dye staining demonstrated nuclear condensation and fragmentation. Chromosomal DNA cleavage detected as DNA ladder pattern by gel electrophoresis including activation of cellular caspase-3 activity, a hallmark of apoptosis, were observed in all treated cancer cell lines. These characteristics suggested the mechanism of apoptosis cell death induced by the extracts. No growth inhibition and apoptosis characteristic were detected in normal cells even at high concentration used suggesting the selective cytotoxicity and potential candidates to develop as anticancer agents.

Optimization of feeding strategy for the ergosterol production by yeasts saccharomyces cerevisiae / Optimización de la estrategia de alimentación para la producción de ergosterol por levaduras saccharomyces cerevisiae

Objective of this study was to optimize ergosterol production by yeast strain Saccharomyces cerevisiae with the use of computer controlled feeding of cultivation medium. Baker´s yeasts strain of Saccharomyces cerevisiae originally modified and selected as mutant D7 was further applied in an industrial scale and also in this investigation. Composition of cultivation medium was optimized with the use of a modified Rosenbrock´s method with regard to following components: glucose, yeast extract, ammonium sulphate, potassium dihydrogen phosphate, magnesium sulphate and calcium chloride. Cultivation of yeast culture was performed in 7 L laboratory bioreactor with a working volume of 5 L equipped with a control unit and linked to a computer, with dissolved oxygen tension measurement, oxygen and carbon dioxide analyzers. BIOGENES prototype software was created from the commercial control system Genesis for Windows 3.0 (GFW), from Iconics and CLIPS 6.04 for the PC-Windows platform. From various factors affecting sterol biosynthesis a specific growth rate was chosen. Feed rate was controlled according to mathematical model. In this case it dealt with a design of optimal profile of specific growth rate with consequent calculation of carbon dioxide profile. Sterol concentration in the dry biomass increased from 1.0 % up to 3 %.

El objetivo de este estudio fue optimizar la producción de ergosterol por una cepa de levadura Saccharomyces cerevisiae, controlando la alimentación de medio de cultivo por computadora. La cepa de levadura panadera Saccharomyces cerevisiae originalmente modificada y seleccionada como mutante D7 fue posteriormente utilizada a escala industrial y también para esta investigación. La composición del medio de cultivo fue optimizada usando el método modificado de Rosenbrock respecto a los siguientes componentes: glucosa, extracto de levadura, sulfato de amonio, fosfato dihidrógeno de potasio, sulfato de magnesio y cloruro de calcio. El cultivo de las células de levadura se llevó a cabo en un biorreactor de laboratorio de 7L con un volumen de trabajo de 5L, equipado con una unidad de control conectada a una computadora, con medición de la tensión de oxígeno disuelto y analizadores de oxígeno y dióxido de carbono. Un software prototipo BIOGENES fue creado a partir del sistema de control comercial Genesis para Windows 3.0 (GFW), de Iconics y CLIPS 6.04 para la plataforma de PC-Windows. A partir de varios factores que afectan la biosíntesis de esterol se escogió una tasa específica de crecimiento. La tasa de alimentación se controló mediante un modelo matemático. En este caso, se trató con un diseño de perfil óptimo de tasa de crecimiento específico con un consecuente cálculo del perfil de dióxido de carbono. La concentración de esterol en la biomasa seca se incrementó desde 1,0% hasta 3%.

Estudios de bioadsorción de plomo por saccharomyces cereviceae en soluciones acuosas / Studies of lead biosorption by saccharomyces cereviceae in aqueous solutions

El ecosistema del lago Titicaca (Puno, Perú) y sus tributarios, viene siendo perturbado por metales pesados producto de la actividad minera emergente. Para controlar y reducir la contaminación existen procesos biológicos llevados a cabo por microorganismos como las levaduras (biorremediación). Este trabajo de investigación tiene como objetivos evaluar la capacidad de bioadsorción de plomo mediante Saccharomyces cereviceae en soluciones acuosas y la influencia de dos niveles de pH durante la bioadsorción. Para esto se ensayaron dos concentraciones de S. cereviceae (cel/mL), las cuales fueron cuantificadas por un hemocitómetro y luego traspasadas a una solución con concentraciones conocidas de plomo (5 y 25 mg/L). Se realizaron lecturas de las concentraciones de plomo a los 5, 60 y 120 minutos. La mayor capacidad de bioadsorción resultó cuando S. cereviceae estaba a una concentración de 5 x 106 cel/mL, y el pH óptimo fue de 5,14. Se concluye que S. cereviceae constituye una buena alternativa para la bioadsorción de plomo, quedando abierta su validación en condiciones de campo en el altiplano peruano.

Lake Titicaca's ecosystem and that of its tributaries in Puno (Peru) are being disturbed by heavy metals resulting from emergent mineral activity. Biological processes involving microorganisms such as yeasts (bioremediation) are being used for controlling and reducing such pollution. This research was aimed at evaluating Saccharomyces cereviceae's lead biosorption capacity in aqueous solutions and evaluating the influence of two pH levels on biosorption. Two S. cereviceae concentrations (cel/mL) were tested; these concentrations were quantified in a haemocytometer and then put into a solution having a known lead concentration (5 and 25 mg/L). Lead concentrations were read after 5, 60 and 120 minutes. The results revealed that the best biosorption level was obtained with a 5 x 106 cel/mL S. cereviceae concentration at 5.14 pH. S. cereviceae thus constitute a good alternative for lead biosorption; however, its validation in Peruvian altiplano field conditions remains to be tested.

Levaduras autóctonas con capacidad fermentativa en la producción de etanol a partir de pulpa de excedentes de plátano musa (AAB Simmonds) en el departamento de Córdoba, Colombia / Autoctonous yeasts having fermentation ability in producing ethanol from Musa (AAB Simmonds) plantain surplus pulp in the Córdoba department of Colombia

Se evaluó la capacidad fermentativa de levaduras nativas de la zona costanera del departamento de Córdoba, Colombia, para la obtención de etanol a partir de la pulpa de excedentes de plátano Musa (AAB Simmonds), con el objetivo de encontrar cepas eficientes. Los microorganismos utilizados correspondieron a las especies: Kloeckera sp, Candida guillliermondii 14AD, Candida albicans y Candida guillliermondii 13AD (nativas), y una cepa comercial de referencia, Saccharomyces cerevisiae T73. La fermentación se realizó a diferentes concentraciones de sustrato, siendo la concentración del 40% la mejor; se evaluó la producción de etanol mediante el método colorimétrico del dicromato de potasio utilizando un equipo espectrofotómetro Lambda 11. Se observó que la levadura Candida guilliermondii 14AD nativa fue la más eficiente con una producción promedio de 3,45% v/v de etanol a las 72 horas de fermentación; no se encontraron diferencias estadísticamente significativas con la producción de etanol a partir de la cepa de referencia, la cual produjo 3,59% v/v. Estos resultados sugieren la existencia de levaduras nativas con capacidad para ser utilizadas en la obtención de etanol a partir de material residuo de plátano.

Native yeasts™ (Cordoba, Colombia) fermentation ability for producing ethanol from plantain (Musa AAB Simmonds) surplus pulp was evaluated; the object was to find efficient yeasts. The microorganisms used here came from the Kloeckera sp, Candida guillliermondii (14AD), Candida albicans and Candida guilllier-mondii 13AD strains (native) and Saccharomyces cerevisiae T73 (a commercial reference yeast). Fermentation was carried out on different substrate concentrations, the 40% one giving the best result; ethanol production was evaluated by the potassium dichromate colorimetric method using a Lambda 11 spectrophotometer. It was observed that the Candida guilliermondii 14AD native yeast was the most efficient, having an average 3.45% v/v ethanol production after 72 hours’ fermentation. There were no statistically significant differences compared to reference yeast strain ethanol production (3.59% v/v). These results suggest that native yeasts can be used in obtaining ethanol from residual plantain matter.

Comparative study between yeasts immobilized on alumina beads and on membranes prepared by two routes

Alumina channeled beads and rough surface membranes prepared from aqueous sols of fibrillar pseudoboehmite are able to immobilize yeasts for ethanol fermentation of sugar solutions. This paper describes comparative results of assays carried out with yeasts immobilized onto alpha-alumina beads and membranes prepared under two different conditions of processing and firing. The fermentation tests evaluated by the decrease of fermentable sugars, referred as Brix degrees per hour, indicated that the yeasts immobilized on beads had similar performance, probably because their surfaces, even being morphologically different, presented the same value of open porosity. One type of membrane (asymmetrical; precursor: pseudoboehmite; firing temperature 1,150liC; crystal structure; alpha-alumina) had better performance than the other type (asymmetrical; precursor: fibrillar pseudoboehmite plus aluminum hydroxiacetate mixture; 1,150liC; alpha-alumina) because the yeast cells entered into their porous interior through the surface slits, were immobilized and their growth was easier than on the external surface.

Aislamiento, identificación y serotipificación del flujo vaginal en pacientes con clínica de vaginitis / Isolation, identificatión and serotyping of vaginal flux in patients with vaginitis clinical

Se realizó un estudio en 105 pacientes con clínica de vaginitis que asistieron a la consulta de la Unidad de Enfermedades Infecciosas del Hospital Vargas referidas del Servicio de Ginecología, CUEI HV, con el fin de investigar la presencia de levaduras del género Candida. Se observó la presencia de levaduras en 23 casos (22 por ciento) de las cuales 12 fueron C.albicans, 5 C.tropicalis, 3 C.guilliermondii, 2 glabrata y 1 C.parapsilosi. La presencia de hifas fue observada en un 50 por ciento de los exámenes directos, en donde la especies no albacans. En este estudio de muestras vaginales, se observó muy poca diferencia entre los porcentajes del serotipo A y B, teniéndose un 58 por ciento de serotipo A y 42 por ciento del B, lo que contrasta con otros estudios realizados en Venezuela y otras localidades geográficas, en muestras clínicas diferentes, en donde el serotipo A se presenta con una incidencia más significativa al serotipo B. Esto nos sugiere que en la candidiasis vaginal parece encontrarse con mayor frecuencia el serotipo B de C.albicans

Efeito de extrato de levedura e pH do meio de cultura na produçäo de poligalacturonase por Penicillium expansum / Effect of yeast extract and medium ph on polygalacturonase production by penicillium expansum

Resumo: A atividade de poligalacturonase extracelular de Penicillium expasum foi dosada nos filtrados das culturas, após a remoçäo da massa micelial, a qual foi usada na determinaçäo do crescimento do microrganismo. As mulhores condiçöes de crescimento para produçäo de enzima, foram o uso de meio mineral näo tamponado e ausência de extrato de levedura. A produçäo da enzima foi dependente do pH do meio de crescimento, sendo em pH ácido (au)

Características de uma nova linhagem de levedura "Killer" / Study of some characteristics of newly isolated killer yeas

Foi isolada uma nova linhagem de Saccharomyces cerevisuiae 337, de usina de cana de açucar, que apresentou ativudade "Killer" semelhante ao fenótipo K.A eletroforese em gel de agarose mostrou que a linhagem S.cerevisiae 337 possui dois ds-RNAs. A atividade "killer" da linhagem foi comparada com a levedura padräo"Killer" K

Estudio de la composición química de biomasas celulares de levaduras / Chemical composition of the cellular biomass of yeasts

El objetivo de este trabajo fue analziar cepas de levaduras de posible utilización en laimentos animal, obtenidas por fermentación en sistema batch, utilizando suero efluetne de quesería como sustrado hidrocarbonado principal. Para el caso, se precedío al análisis químico de 10 cepas de levaduras seleccionadas en base a su capacidad productora de biomasa. Según revelaron los resultados obtenidos, la composición química de las mismas es muy variable, presentando en todos los casos un alto contenido proteínico, buena solubilidad, u digestibilidad enzimática. En todas ellas, el tenor de RNA es bajo, siendo este valor importante cuando la biomasa se destina a la alimentación humana. Por otra parte, el contenido en aminoácidos esenciales es adecuado, aunque deficitario en aminoácidos azufrados. De las levaduras sometidas a ensayo, se destaca la N§ 10: Kluyveromyces marxianus var. lactis por su adecuada relación entre el contenido proteínico y el de RNA, así como por la detección de metionina entre sus aminoácidos esenciales