ABSTRACT
ABSTRACT During the most recent decades, advances have been made to reduce the environmental impact by anthropogenic activities that constantly release toxic components into the environment, generating instability and damage to the health of biological communities. Among the different pollutants, heavy metals are important by virtue of their properties, which hinder their degradation or transformation into other less toxic compounds. Chromium is one of the metals of greatest global interest due to its use in multiple industries. Conventional methods using chromed materials in their processes, not only throw considerable amounts of waste into the environment, but also give little account of the fraction of hexavalent chromium (Cr6+) present in certain ecosystems. Bioremediation has been proposed as an economically viable and environmentally sustainable alternative. This work aimed to evaluate the chromium reduction capacity by bacteria isolated from a biosolids matrix obtained at the San Fernando Wastewater Treatment Plant (WWTP), located in Medellín (Colombia). Biosolids samples were grown in a nutrient agar enriched with different concentrations of Cr6+. The strains presenting the greater tolerance to chromium were isolated to perform reduction tests by triplicate, monitoring the concentration of the metal over time. Seven different bacterial species were obtained, among which Staphylococcus saprophyticus, Ochrobactrum anthropic, and Bacillus cereus showed the greatest ability to reduce Cr6+ (29.0%, 61.1 and 100%, at 96 h) respectively.
RESUMEN En las últimas décadas se ha trabajado activamente para reducir el impacto ambiental generado por las actividades antrópicas que constantemente liberan componentes tóxicos al ambiente generando inestabilidad y daños en la salud de las comunidades biológicas. Entre los diferentes contaminantes, los metales pesados revisten importancia en virtud de sus propiedades, que dificultan su degradación o transformación en otros compuestos menos tóxicos. El cromo es uno de los metales de mayor interés a nivel global por su uso en múltiples industrias. Los métodos convencionales que utilizan materiales cromados en sus procesos, no sólo arrojan cantidades considerables de residuos al ambiente, sino que dan poca cuenta de la fracción de Cr6+ presente en determinados ecosistemas. La biorremediación se ha propuesto como una alternativa económicamente viable y ambientalmente sostenible. El propósito del presente trabajo fue evaluar la capacidad de reducción de cromo por bacterias, aisladas de una matriz de biosólidos de la Planta de tratamiento de aguas residuales (PTAR) San Fernando en la ciudad de Medellín-Colombia. Muestras de biosólidos se cultivaron en Agar Nutritivo enriquecido con diferentes concentraciones de Cr6+. Las cepas que presentaron mayor tolerancia al cromo fueron aisladas para realizar ensayos de reducción por triplicado, monitoreando la concentración del metal en el tiempo. Se obtuvieron siete especies bacterianas diferentes dentro de las cuales se destacaron Staphylococcus saprophyticus, Ochrobactrum anthropi y Bacillus cereus por la capacidad de reducir Cr6+ a 96 h con eficiencias de 29.0%, 61.1% y 100%, respectivamente.
ABSTRACT
Background: Functional Foods are considered nowadays by consumers as the range of foods of major interest. Objectives: The aim of the present work was the evaluation of color, texture and sensorial properties of fresh Cape Gooseberry (FG) and vacuum impregnated Cape Gooseberry (IG) with calcium and vitamins B9, C, D and E during storage at 4ºC. Methods: Entire cape gooseberries were vacuum impregnated (VI) with tocopherol and cholecalciferol emulsified in aqueous phase with sucrose, ascorbic acid, folic acid, calcium chloride, calcium fumarate, low methoxyl pectin, isolated soy protein, tensoactives and preservatives. The texture was determined from puncture assays, and the color from the CIE Lab coordinates. The sensorial profile was determined with the aid of trained panelists, through a multidimensional approach of characteristic descriptors of general appearance, odor, taste and texture. Results: The instrumental values of color and texture for IG were significantly different from the FG, because are being softer, more elastic, darker, brighter and of less color saturation. The samples of FG and IG presented intense sensorial characteristics in the descriptors orange color, brightness, spherical uniformity, smooth surface, fresh appearance, odor, cape gooseberry characteristic taste and frutal, fleshy texture, juicy, firmness and turgidity. By the effect of VI process the most relevant significant differences were the descriptors orange color, superficial stains, fresh appearance, sweet taste and cape gooseberry characteristic taste, soft texture, firmness and juicy; whereas for the effect of storage time were fresh appearance, dehydrated appearance, peduncle cicatrization, aromatic odor, overripe, cape gooseberry characteristic taste, frutal taste, soft texture, juicy, firmness and turgidity. Conclusions: The VI significantly affects the objective assessment of color and texture, finding correspondence with the sensorial evaluation...