Efecto de la doble inducción con galactosa y hierro en la producción de sustancias poliméricas extracelulares en Acidithiobacillus ferrooxidans y la adherencia microbiana a un mineral aurífero refractario.

Abstract

Abstract: Microbial attachment mechanisms in Acidithiobacillus ferrooxidansare mediated by extracellular polymeric substances (EPS). EPS production responds to environmental conditions. In this work, the double induction of EPS with galactose and Fe3+in Acidithiobacillus ferrooxidansin planktonic phase and its effect on mineral attachmentwas evaluated. Acidithiobacillusferrooxidanswas adapted to galactose (0%, 0.15% and 0.25% (m/v)) and Fe2+(9 g/L and 18 g/L) in defined culture medium. EPS production was determined at peak growth time and in addition, its effect on mineral attachment. The results showed a maximum cell attachment of 94.1% within 2 hours at 0.15% of galactose and 18g/L of Fe3+concentrations compared to 71.4% without galactose and 9g/L of Fe3+. The single effect of high iron3+ concentrations result in 79% of cell attachment. The maximum concentration of EPS was obtained with 0.25%ofgalactose.However, it did not result in greater attachmentcompared to concentrations of 0.15% galactose. Through the combined induction of galactose and Fe3+, it was possible to increase the percentage of bacterial adherence and, therefore, an increase in the rate of biooxidation.