Bioprospecting of extremophilic perchlorate-reducing bacteria: report of promising Bacillus spp. isolated from sediments of the bay of Cartagena, Colombia.

Three extremophile bacterial strains (BBCOL-009, BBCOL-014 and BBCOL-015), capable of degrading high concentrations of perchlorate at a range of pH (6.5 to 10.0), were isolated from Colombian Caribbean Coast sediments. Morphological features included Gram negative strain bacilli with sizes averaged of 1.75 × 0.95, 2.32 × 0.65 and 3.08 × 0.70 µm, respectively. The reported strains tolerate a wide range of pH (6.5 to 10.0); concentrations of NaCl (3.5 to 7.5% w/v) and KClO4- (250 to 10000 mg/L), reduction of KClO4- from 10 to 25%. LB broth with NaCl (3.5-30% w/v) and KClO4- (250-10000 mg/L) were used in independent trials to evaluate susceptibility to salinity and perchlorate, respectively. Isolates increased their biomass at 7.5 % (w/v) NaCl with optimal development at 3.5 % NaCl. Subsequently, ClO4- reduction was assessed using LB medium with 3.5% NaCl and 10000 mg/L ClO4-. BBCOL-009, BBCOL-014 and BBCOL-015 achieved 10%, 17%, and 25% reduction of ClO4-, respectively. The 16 S rRNA gene sequence grouped them as Bacillus flexus T6186-2, Bacillus marisflavi TF-11 (T), and Bacillus vietnamensis 15 - 1 (T) respectively, with < 97.5% homology. In addition, antimicrobial resistance to ertapenem, vancomycine, amoxicillin clavulanate, penicillin, and erythromycin was present in all the isolates, indicating their high adaptability to stressful environments. The isolated strains from marine sediments in Cartagena Bay, Colombia are suitable candidates to reduce perchlorate contamination in different environments. Although the primary focus of the study of perchlorate-reducing and resistant bacteria is in the ecological and agricultural realms, from an astrobiological perspective, perchlorate-resistant bacteria serve as models for astrobiological investigations.

Studies of Endocrine Disruptors: Nonylphenol and Isomers in Biological Models.

Certain emerging pollutants are among the most widely used chemicals globally, causing widespread concern in relation to their use in products devoted to cleaniness and asepsis. Nonylphenol ethoxylate (NPEOn) is one such contaminant, along with its degradation product, nonylphenol, an active ingredient presents in nonionic surfactants used as herbicides, cosmetics, paints, plastics, disinfectants, and detergents. These chemicals and their metabolites are commonly found in environmental matrices. Nonylphenol and NPEOn, used, are particularly concerning, given their role as endocrine disruptors chemical and possible neurotoxic effects recorded in several biological models, primarily aquatic organisms. Limiting and detecting these compounds remain of paramount importance. The objective of the present review was to evaluate the toxic effects of nonylphenol and NPEOn in different biological models. Environ Toxicol Chem 2023;42:1439-1450. © 2023 SETAC.

Perchlorate-reducing bacteria from Antarctic marine sediments.

Perchlorate is a contaminant that can persist in groundwater and soil, and is frequently detected in different ecosystems at concentrations relevant to human health. This study isolated and characterised halotolerant bacteria that can potentially perform perchlorate reduction. Bacterial microorganisms were isolated from marine sediments on Deception, Horseshoe and Half Moon Islands of Antarctica. The results of the 16S ribosomal RNA (rRNA) gene sequence analysis indicated that the isolates were phylogenetically related to Psychrobacter cryohalolentis, Psychrobacter urativorans, Idiomarina loihiensis, Psychrobacter nivimaris, Sporosarcina aquimarina and Pseudomonas lactis. The isolates grew at a sodium chloride concentration of up to 30% and a perchlorate concentration of up to 10,000 mg/L, which showed their ability to survive in saline conditions and high perchlorate concentrations. Between 21.6 and 40% of perchlorate was degraded by the isolated bacteria. P. cryohalolentis and P. urativorans degraded 30.3% and 32.6% of perchlorate, respectively. I. loihiensis degraded 40% of perchlorate, and P. nivimaris, S. aquimarina and P. lactis degraded 22%, 21.8% and 21.6% of perchlorate, respectively. I. loihiensis had the highest reduction in perchlorate, whereas P. lactis had the lowest reduction. This study is significant as it is the first finding of P. cryohalolentis and. P. lactis on the Antarctic continent. In conclusion, these bacteria isolated from marine sediments on Antarctica offer promising resources for the bioremediation of perchlorate contamination due to their ability to degrade perchlorate, showing their potential use as a biological system to reduce perchlorate in high-salinity ecosystems.

Presence of perchlorate in marine sediments from Antarctica during 2017-2020.

Perchlorate of natural origin is a persistent pollutant that affects thyroid function by inhibiting iodine uptake, and this pollutant is frequently detected in different ecosystems at concentrations that can harm human health. In this study, we measured the perchlorate concentrations in 3,000 marine sediment samples from January to March in 2017, 2018, 2019, and 2020 during the 3rd, 4th, 5th, and 6th Colombian Scientific Expeditions to Antarctica. The sampling zones were located at 15 different points on the South Shetland Islands and Antarctic Peninsula, and they were measured using a selective perchlorate electrode. The concentration data indicate that perchlorate reached a minimum concentration of 90 ppm on Horseshoe Island and a maximum concentration of 465 ppm on Deception Island, suggesting a spatial variation in perchlorate concentrations that can be attributed to the natural formation of this pollutant due to volcanic eruptions. Additionally, homogeneous distribution of perchlorate was not observed in Antarctica.

Perchlorate Contamination: Sources, Effects, and Technologies for Remediation.

Perchlorate is a persistent pollutant, generated via natural and anthropogenic processes, that possesses a high potential for endocrine disruption in humans and biota. It inhibits iodine fixation, a major reason for eliminating this pollutant from ecosystems. Remediation of perchlorate can be achieved with various physicochemical treatments, especially at low concentrations. However, microbiological approaches using microorganisms, such as those from the genera Dechloromonas, Serratia, Propionivibrio, Wolinella, and Azospirillum, are promising when perchlorate pollution is extensive. Perchlorate-reducing bacteria, isolated from harsh environments, for example saline soils, mine sediments, thermal waters, wastewater treatment plants, underground gas storage facilities, and remote areas, including the Antarctica, can provide removal yields from 20 to 100%. Perchlorate reduction, carried out by a series of enzymes, such as perchlorate reductase and superoxide chlorite, depends on pH, temperature, salt concentration, metabolic inhibitors, nutritional conditions, time of contact, and cellular concentration. Microbial degradation is cost-effective, simple to implement, and environmentally friendly, rendering it a viable method for alleviating perchlorate pollution in the environment.

Perchlorate-Reducing Bacteria from Hypersaline Soils of the Colombian Caribbean.

Perchlorate (ClO4 -) has several industrial applications and is frequently detected in environmental matrices at relevant concentrations to human health. Currently, perchlorate-degrading bacteria are promising strategies for bioremediation in polluted sites. The aim of this study was to isolate and characterize halophilic bacteria with the potential for perchlorate reduction. Ten bacterial strains were isolated from soils of Galerazamba-Bolivar, Manaure-Guajira, and Salamanca Island-Magdalena, Colombia. Isolates grew at concentrations up to 30% sodium chloride. The isolates tolerated pH variations ranging from 6.5 to 12.0 and perchlorate concentrations up to 10000 mg/L. Perchlorate was degraded by these bacteria on percentages between 25 and 10. 16S rRNA gene sequence analysis indicated that the strains were phylogenetically related to Vibrio, Bacillus, Salinovibrio, Staphylococcus, and Nesiotobacter genera. In conclusion, halophilic-isolated bacteria from hypersaline soils of the Colombian Caribbean are promising resources for the bioremediation of perchlorate contamination.

Ecotoxicological assessment of perchlorate using in vitro and in vivo assays.

Perchlorate is an inorganic ion widespread in the environment, generated as a natural and anthropogenic pollutant, with known endocrine disruption properties in the thyroid gland. Nonetheless, there are few reports of its ecotoxicological impact on wildlife. The aim of this study was to evaluate the adverse effects of KClO4 exposure on different cell lines, HEK, N2a, and 3T3, as well as in ecological models such as Vibrio fischeri, Pseudokirchneriella subcapitata, Daphnia magna, and Eisenia fetida. Perchlorate exhibited similar toxicity against tested cell lines, with LC50 values of 19, 15, and 19 mM for HEK, N2a, and 3T3, respectively; whereas in V. fischeri, the toxicity, examined as bioluminescence reduction, was considerably lower (EC50 = 715 mM). The survival of the freshwater algae P. subcapitata was significatively impaired by perchlorate (LC50 = 72 mM), and its effect on the lethality in the crustacean D. magna was prominent (LC50 = 5 mM). For the earthworm E. fetida, the LC50 was 56 mM in soil. In this organism, perchlorate induced avoidance behavior, weight loss, and decreased egg production and hatchling, as well as morphological and histopathological effects, such as malformations, dwarfism, and necrosis. In conclusion, perchlorate toxicity varies according to the species, although E. fetida is a sensitive model to generate information regarding the toxicological impact of KClO4 on biota.