Psychrobacter sp: perchlorate reducing bacteria, isolated from marine sediments from Margarita Bay, Antarctica.

Abstract

Perchlorate (ClO -) is an ion that occurs naturally in Antarctica, it is considered an emerging pollutant because it is a powerful endocrine disruptor that affects the functioning of the thyroid gland and the growth and development of humans and biota. The objective of this study was to characterize salt-tolerant bacteria that reduce (ClO -) from marine sediments of Bahía Margarita, Antarctica, collected in the V Colombian Scientific Expedition to Antarctica "Almirante Tono" in 2019. The methodology used included three stages: [1] Isolation of the bacteria: for which broth and LB agar modified with seawater were used [2] Morphological and biochemical characterization of the isolated strains: through Gram staining, tests for catalase, oxidase and BBL Crystal; [3] Susceptibility tests (NaCl and ClO -) and ClO4-reduction test using selective electrode. The bacterial isolates grew at 10 °C for 7 days, tolerated NaCl concentrations up to 20% v/v and (ClO -)concentrations up to 10,000 mg/L; with pH variations between 6.5 to 12.0. This contaminant was reduced by the isolated strains in percentages between 18% and 41%. The morphological and biochemical characterization of the isolated strains indicated that they were related to the genus Psychrobacter. In conclusion, salttolerant bacteria isolated from marine sediments in Margarita Bay, Antarctica are promising resources for bioremediation of (ClO -) pollution in ecosystems. Keywords-extreme environments, halotolerant bacteria, marine sediments, polar environments, toxicity.