Pseudomonas sp. Bacteria: potentially toxic metal-contaminated soil remediation potentials - minimum inhibitory concentration investigation and application

Abstract

Agricultural inputs used for correction or nutrition in agriculture have a composition that, in addition to containing desirable elements, often includes potentially toxic metals that contaminate the soil. Faced with this scenario, one can observe the appearance of various remediation techniques, amongst them, bio-remediation. This technique has been shown to be highly promising, as there is a wide variety of genera and species of microorganisms. In this study, the application of Pseudomonas sp. bacteria in soil from bean cultivation was investigated, with the aim of removing Zn2+ and Ni2+ ions. Analyzes were carried out of soil parameters, pH in water and KCl, Zero Charge Point, exchangeable acidity, quantity of organic matter in soil and initial concentrations of ions. To evaluate the tolerance of bacteria to metal concentrations in the soil, studies of Minimum Inhibitory Concentration were conducted. A bioremediation experiment was then carried out, applying the bacteria to the soil and monitoring the process over 21 days. The results showed that Pseudomonas sp. bacteria showed good resistance to high metal concentrations, as well as remarkable capacity and efficiency in the absorption of metals, reaching 0,063 mg kg-1 and 90.5% efficiency in the removal of Ni2+ ions, and 0,012 mg kg-1 capacity and 47.9% efficiency in the removal of Zn2+ ions. These results suggest that the Pseudomonas sp. bacteria are promising for the bioremediation of soils contaminated with potentially toxic metals.