ABSTRACT
RESUMEN Las aguas de desecho dispuestas en una corriente superficial, lagos, ríos, mar, sin ningún tratamiento, ocasionan graves inconvenientes de contaminación, que afectan la flora y la fauna. Estas aguas residuales, antes de ser vertidas en las masas receptoras, deben recibir un tratamiento adecuado, capaz de modificar sus condiciones físicas, químicas y microbiológicas, para evitar que su disposición cause la alteración y la degradación de los ecosistemas asociados y problemas de salud pública. La investigación tuvo como objetivo evaluar el efecto de mezclas de quitosano y extracto acuoso de la cáscara de naranja, a diferentes concentraciones, en el proceso de coagulación-floculación, de aguas residuales, para lo cual, se realizó una prueba de jarras con agitación rápida y lenta, para evaluar turbidez (NTU), demanda química de oxígeno (DQO), demanda bioquímica de oxígeno (DBO), sólidos suspendidos totales (SST) y SS (sólidos sedimentables). Los resultados mostraron que todos los tratamientos presentaron diferencias significativas (p<0,05), con la muestra control y fueron eficientes en la reducción de turbidez, DBO, DQO, SST, SS. El tratamiento que combinó quitosano y extracto acuoso de cáscara de naranja (50-50%), a un pH de 5,5, disminuyó significativamente (p<0,05) la turbidez, en 79%, demostrando, de manera preliminar, que el extracto acuoso de la cáscara de naranja acidifica la mezcla e incrementa la formación de flóculos aglomerados en una fase liviana de las muestras, convirtiéndose en un agente eficiente, para ser usado en el tratamiento de aguas residuales.
ABSTRACT Waste water disposed in a superficial current, lakes, rivers, the sea, without any treatment, causes great inconvenient pollution that affects the flora and fauna of a region. This wastewater, before being poured into the receiving body of water, must receive the appropriate treatment, in order to modify its physical, chemical and microbiological conditions, to avoid that its disposal causes the alteration and degradation of the associated ecosystems and problem with public health. This research had as an objective to assess the effect of chitosan and aqueous extract of orange peel shells at different concentrations on the coagulation-flocculation process of wastewater. In order to do this, a jar test with fast and slow pull was carried out, assessing turbidity (NTU), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total suspended solids (TSS) and SS (solid sediments). The results showed that all the treatments presented significant differences (p<0.05) to the control sample, and were efficient in the decrease of NTU, DQO, DBO, SST, and SS. The treatment that combined chitosan and aqueous extract of orange peel (50-50%) at a pH or 5.5, decreased significantly (p<0.05) the turbidity in a 79%, showing in a preliminary way that the aqueous extract of orange peel shells acidifies the mix and increases the formation of agglomerated floccules in a light phase of the samples, becoming an efficient agent to be used in the treatment of wastewater.
ABSTRACT
Breadfruit is an exotic tree in Brazil, very well acclimatized. Despite of being a laticifer plant, the knowledge about its latex is scarce. However, it is known that proteolytic enzymes represents over 50% of the latex composition in laticifers plants. The aim of this study was to evaluate the potential of breadfruit (Artocarpus altilis var. Apyrena) latex as a source of milk clotting proteases and partially characterize it. The proteolytic activity of the fraction of crude extract was assessed using azocasein and quantitation of total protein, the bicinchoninic acid (BCA). Milk-clotting activity was analyzed using skim milk at 12%. The enzyme activity was analyzed under different temperature conditions (35 to 80°C) and pH (5.8 to 10.7) presenting optimum activity in alkaline pH (8.5) and 50°C; being stable to the two variables at 120 minutes during the test. The clotting activity was directly proportional to the temperature at the better concentration of CaCl2 (10mmol L-1). The results indicate that enzyme is a possible replacement for calf rennet.
A fruta-pão é uma árvore exótica no Brasil, onde se aclimatou muito bem. Embora seja uma planta lactífera, o conhecimento sobre seu látex é escasso. No entanto, sabe-se que enzimas proteolíticas correspondem a mais de 50% da composição do látex em plantas lactíferas. O objetivo deste estudo foi avaliar o potencial do látex da fruta-pão (Artocarpus altilis var. Apyrena) como fonte de protease coagulante do leite e caracterizar parcialmente a enzima. A atividade proteolítica da fração de extrato bruto foi avaliada utilizando azocaseína e, para a quantificação das proteínas totais, o ácido bicinconínico (BCA). A atividade de coagulação do leite foi testada utilizando leite desnatado a 12%. A protease foi testada em diferentes condições de temperatura (35 a 80°C) e pH (5,8 a 10,7) e apresentou atividade ótima a 50°C e pH alcalino (8,5) sendo estável a estas variáveis durante 120 minutos. A atividade coagulante no leite foi diretamente proporcional à temperatura na melhor concentração de CaCl2 a 10µmol L-1. Os resultados indicam que a enzima analisada é uma possível alternativa à quimosina.
ABSTRACT
Cryptosporidium es uno de los microorganismos de mayor interés desde el punto de vista de la Salud Pública y constituye un problema prioritario para las plantas y organismos reguladores de agua. Debido a su pequeño tamaño y a su resistencia a la cloración, la eliminación por el proceso de potabilización es una tarea compleja. En este trabajo se analizó la efectividad de distintos coagulantes utilizados comúnmente en tal proceso para lograr la remoción de los ooquistes. Se trabajó con la prueba de jarras (Jar Test). Se halló que: 1) Los coagulantes con agregado de polímeros coadyuvantes producen remociones de ooquistes superiores a 2 log. 2) Un valor bajo de turbiedad no asegura una remoción óptima de los parásitos. 3) La adición de polielectrolitos al cloruro férrico disminuye la variabilidad tanto en la turbiedad final como en la eliminación de Cryptosporidium.
Cryptosporidium is one of the microorganisms of main concern from the point of view of Public Health, being a priority problem for water treatment plants and water regulatory institutions. Due to its small size and resistance to chlorination, Cryptosporidium removal during the process of drinking water treatmentis a hard task. The effectiveness of different coagulants commonly used in the process of removal of oocysts was analyzed. Thetechnique used was the Jar Test. It was found that: 1) coagulants with the addition of polimeric coadjuvants produce over 2 logs of oocyst removal; 2) a low value in turbidity does not necessarily mean optimal parasite removal, and 3) the addition of polyelectrolites to ferric chloride diminishes variability, both in final turbidity and Cryptosporidium removal.