Aislamiento y determinaci?n de bacterias biooxidantes del g?nero Acidithiobacillus y Leptospirillum presentes en las aguas residuales de las unidades mineras de Recuay ? Huaraz

Abstract

La presente investigaci?n tuvo como objetivo el aislamiento y determinaci?n de las bacterias del g?nero Acidithiobacillus y Leptospirillum presentes en las aguas residuales de las unidades mineras de Recuay ? Huaraz. Con este fin se recolectaron 3 muestras del efluente y se llevaron al laboratorio donde fueron sometidas al enriquecimiento en medios de cultivo 9K y T?K l?quidos, con un pH de 1.5 y se realiz? un conteo poblacional cada 24 horas haciendo uso de la c?mara de Newbauber. Se obtuv? la mayor concentraci?n bacteriana en el tratamiento 1 con 9.33E+06 cel/ml durante la etapa de enriquecimiento. Por otro lado, para el aislamiento del cultivo se utiliz? medio 9K l?quido y s?lido; el primero fue incubado a temperatura ambiente por 8 d?as. Transcurrido este tiempo se sembr? en placas Petri, por estr?a y por extensi?n. En medio s?lido 9K con agar-agar se observ? crecimiento bacteriano despu?s de 14 a 25 d?as, en el 50% de placas sembradas por extensi?n y el 10% por estr?a. Mientras que en el medio cultivo 9K con agarosa se observ? crecimiento despu?s de 7 a 8 d?as en el 80% y 60% de placas por extensi?n y estr?a, respectivamente. Los resultados de la observaci?n microsc?pica mostraron presencia de bacterias con morfolog?a bacilar, car?cter acid?filo por su desarrollo en medios con pH 1.5 y metabolismo quimiolitiotrofo por su crecimiento y mantenimiento durante el tiempo del ensayo a expensas de compuestos inorg?nicos presentes en el medio. En el medio s?lido con crecimiento bacteriano despu?s de 45 d?as de incubaci?n se logr? diferenciar 3 tipos de colonias que coinciden con el g?nero de Acidithiobacillus . Adem?s se obtuvieron indicios de las biotransformaciones realizadas por las bacterias lixiviadoras, oxidando el sulfato ferroso a sulfato f?rrico durante la determinaci?n de bioxidaci?n, lo cual se evidenci? mediante el cambio de color de verde trasl?cido a naranja brillante.The present investigation had as objective the isolation and determination of the species of the genus Acidithiobacillus and Leptospirillum present in the waste water of the mining units of Recuay - Huaraz. To this end, 3 samples of the effluent were collected and taken to the laboratory where they were submitted to enrichment in 9K and T & K liquid culture media, with a pH of 1.5 and a population count was done every 24 hours using the Newbauber chamber. The results showed that the best enrichment was carried out with the medium 9k in agitation 150 rpm, extra aeration and heat 40 ? C, as the bacterial growth curve occurred in ascending and sustained form, being at 432 hours where Observed the highest bacterial concentration, 9.33E + 06 cells / ml. On the other hand, liquid and solid 9K medium were used for the isolation of the culture; The first was incubated at room temperature for 8 days. After this time was planted in Petri plates, by stria and by extension. In solid 9K medium with agar-agar bacterial growth was observed after 14 to 25 days, in 50% of plates seeded by extension and 10% by streak. While in the 9K medium agarose culture growth was observed after 7 to 8 days in 80% and 60% plates by extension and stria, respectively. The results of the microscopic observation showed the presence of bacteria with bacillary morphology, acidophilic character due to their development in media with pH 1.5 and chemiolithotroph metabolism due to their growth and maintenance during the time of the test at the expense of inorganic compounds present in the medium. In solid medium with bacterial growth after 45 days of incubation it was possible to differentiate 3 types of colonies. In addition, indications were obtained of the biotransformations performed by the leaching bacteria, oxidizing the ferrous sulfate to ferric sulfate during the determination of biooxidation. Which was evidenced by the change of color from translucent green to bright orange.