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The study on the bioleaching of metals from minerals is a necessity to improve the process of recovering precious metals and obtaining greater benefits. The objective was to determine in four successive reactivations, the specific growth rate and stability of microbial consortia obtained from the leaching plant of the mining company Southern Cooper Corporation (SCC) in Toquepala, Tacna - Peru. The consortia M-1, M-2, M-5, M-6, and BF-7 were obtained from chalcopyrite from the leach heaps; and the PLS-3, PLS-4, and ILS-8 of the leached liquid solutions. The liquid culture medium used was modified to 9K. The consortia had four successive reactivations in 9K medium, in triplicate, at room temperature for 15 days and with 1vvm aeration. The microbial counts obtained every eight hours in the Petroff-Hausser counting chamber were converted to the decimal logarithmic scale to obtain the growth kinetics using the Malthusian model that determined the rate constant K in the logarithmic phase and the Gompertz model to the microbial growth curve. The consortia from solid samples and biofilm had a faster adaptation, compared to those from the liquid samples of PLS and ILS, which showed an inactive microbial concentration at the beginning. All consortia after the first reactivation showed higher growth rates, the highest being in the PLS-4 consortium during the third reactivation, with a K of 0.025 h-1. The most stable growth rates occurred in the fourth reactivation in the M-6 and BF-7 consortia, these were the most indicated to continue with application studies as inoculum after a third reactivation and achieve the optimization of the bioleaching process of the mineral chalcopyrite. [ABSTRACT FROM AUTHOR]

In Latin America snapper species have shown great potential for mariculture, including L. guttatus, but it is necessary to study physiological aspects regarding its production. The purpose of this study was to determine the effects of temperature (24, 29 and 34°C) and salinity (15, 25, 35, 45) on the growth and survival of juvenile L. guttatus. All experiments were performed in a recirculation system with daily 300% change of water; in cylindrical 80 L tanks, and three replicates per treatment. 360 specimens were used for the experiments. Experiments were performed with 360 specimens. The results showed that there are differences (P < 0.05) in salinity-temperature interaction. The highest specific growth rate appeared in the treatment of 34°C and salinity of 15. The greatest gain in average body weight was obtained in the treatment of 34°C and salinity of 25. The longer survival was recorded in the treatment of 24°C and salinities of 15 to 35. The low salinity tolerance for this species found shows that L. guttatus has a high potential to grow in lagoon-estuarine systems of low salinity (15) and no more than 35. [ABSTRACT FROM AUTHOR]

The article discusses the development of a specific growth rate model based on the assumption that food availability is the growth-limiting factor in the culture of the filter feeding clam species Venerupis pullastra. The authors discuss the results of their analyses of environmental, physiological, and technological variables on the growth rates of V. pullastra seeds under laboratory conditions.

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El artículo discurre sobre el diseño y el cultivo de una vacuna, denominada VC 638, para la bacteria Vibrio cholerae que causa la enfermedad de cólera. Los autores comentan sobre el proceso de la optimización de la vacuna. También se considera la viabilidad de VC 638 así como la investigación de la velocidad específica de crecimiento de la bacteria.