Abstract

VELEZ, Juan A. et al. Hexavalent chromium-reducing bacteria on biosolids from the San Fernando Wastewater Treatment Plant in Medellín (Colombia). Rev. colomb. biotecnol [online]. 2021, vol.23, n.1, pp.32-45.  Epub Aug 10, 2021. ISSN 0123-3475.  https://doi.org/10.15446/rev.colomb.biote.v23n1.94005.

During the most recent decades, advances have been made to reduce the environmental impact by anthropogenic activities that constantly release toxic components into the environment, generating instability and damage to the health of biological communities. Among the different pollutants, heavy metals are important by virtue of their properties, which hinder their degradation or transformation into other less toxic compounds. Chromium is one of the metals of greatest global interest due to its use in multiple industries. Conventional methods using chromed materials in their processes, not only throw considerable amounts of waste into the environment, but also give little account of the fraction of hexavalent chromium (Cr6+) present in certain ecosystems. Bioremediation has been proposed as an economically viable and environmentally sustainable alternative. This work aimed to evaluate the chromium reduction capacity by bacteria isolated from a biosolids matrix obtained at the San Fernando Wastewater Treatment Plant (WWTP), located in Medellín (Colombia). Biosolids samples were grown in a nutrient agar enriched with different concentrations of Cr6+. The strains presenting the greater tolerance to chromium were isolated to perform reduction tests by triplicate, monitoring the concentration of the metal over time. Seven different bacterial species were obtained, among which Staphylococcus saprophyticus, Ochrobactrum anthropic, and Bacillus cereus showed the greatest ability to reduce Cr6+ (29.0%, 61.1 and 100%, at 96 h) respectively.

Keywords : bacteria; bioremediation; biosolids; chromium; heavy metals; hexavalent; reduction.

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