The removal of metallic species at low concentrations in order to reach the standards required by current legislation has been a challenge. Biosorption can be defined as a physicochemical process that removes substances from an aqueous solution where the sorbent is a biological matrix. This is a fast and reversible binding process between the metallic species and the functional groups present on the surface of the biomass. The main objective of this work was to evaluate the biosorptive capacity of the bacterial strain Rhodococcus erythropolis and banana peel chemically modified on the removal of Ni2 positive and Co2 positive in aqueous solutions in batch. Biosorptive flotation was also evaluated using R. erythropolis due to its high hydrophobicity degree. The appropriate pH value for biosorption with R. erythropolis was around 7 for both metals and for biosorbent modified banana peel was between 6 and 7 for both metals. The results of the uptake capacity of the biosorbents were well adjusted by the Langmuir isotherm model, where the maximum capture capacities using the modified banana peel were 29.35 mg/g for Ni2 positive and 24.70 mg/g for Co2 positive, and, using the Rhodococcus erythropolis bacteria were 14.46 mg/g for Ni2 positive and 16.06 mg/g for Co2 positive. The surface properties of the biosorbents were evaluated before and after interaction with the metallic species in order to determine the possible mechanisms of biosorption, through electrokinetic measurements, infrared spectroscopy and scanning electron microscopy. In the biosorptive flotation experiments it was verified that R. erythropolis presents properties as biocollector and biofrother, achieving removal percentages of 40.20 percent and 23.52 percent for nickel and cobalt, respectively. The results show that although both biosorbents present significant behavior for metal removal at low concentration the modified banana peel showed a greater removal.