Bacteria isolated from explosive contaminated environments transform pentaerythritol tetranitrate (PETN) under aerobic and anaerobic conditions.

Pentaerythritol tetranitrate (PETN) is a nitrate ester explosive that may be persistent with scarce reports on its environmental fate and impacts. Our main objective was to isolate and characterize bacteria that transform PETN under aerobic and anaerobic conditions. Biotransformation of PETN (100 mg L-1) was evaluated using mineral medium with (M + C) and without (M - C) additional carbon sources under aerobic conditions and with additional carbon sources under anaerobic conditions.

Bioremediation of heavy oily sludge: a microcosms study.

Oily sludge is a residue from the petroleum industry composed of a mixture of sand, water, metals, and high content of hydrocarbons (HCs). The heavy oily sludge used in this study originated from Colombian crude oil with high density and low American Petroleum Institute (API) gravity. The residual waste from heavy oil processing was subject to thermal and centrifugal extraction, resulting in heavy oily sludge with very high density and viscosity.

Metagenomic and genomic characterization of heavy metal tolerance and resistance genes in the rhizosphere microbiome of Avicennia germinans in a semi-arid mangrove forest in the tropics.

Mangroves are often exposed to heavy metals that accumulate in the food chain, generate toxicity to mangrove plants and affect microbial diversity. This study determined the abundance of genes associated with resistance and tolerance to heavy metals in the rhizosphere microbiome of Avicennia germinans from a semi-arid mangrove of La Guajira-Colombia by metagenomics and genomics approach. Twenty-eight genes associated with tolerance and 49 genes related to resistance to heavy metals were detected.

Metagenomic Analysis of Biochemical Passive Reactors During Acid Mine Drainage Bioremediation Reveals Key Co-selected Metabolic Functions.

Acid mine drainage (AMD) is the major pollutant generated by the mining industry, and it is characterized by low pH and high concentration of metals and sulfate. The use of biochemical passive reactors (BPRs) is a promising strategy for its bioremediation. To date, there are various studies describing the taxonomical composition of BPR microbial communities, generally consisting of an assemblage of sulfate-reducing organisms inside Deltaproteobacteria, and a diverse set of anaerobic (ligno)cellulolytic bacteria; however, insights about its functional metagenomic content are still scarce.

Liver biomarkers response of the neotropical fish to environmental stressors associated with the oil industry.

The Acacias River in Colombia receives large volumes of industrial effluents mostly derived from the oil industry. To contribute to the study of the possible effects of industrial wastewaters on the aquatic environment and particularly on fish populations, a native neotropical fish, was used as a sentinel species. Wild specimens of were caught at three different places of the Acacias River taking as reference the point of discharge of an oil industry effluent; upstream, downstream, and at the vicinity of the discharge pipe.

Transformation of TNT, 2,4-DNT, and PETN by Raoultella planticola M30b and Rhizobium radiobacter M109 and exploration of the associated enzymes.

The nitrated compounds 2,4-dinitrotoluene (2,4-DNT), 2,4,6-trinitrotoluene (TNT), and pentaerythritol tetranitrate (PETN) are toxic xenobiotics widely used in various industries. They often coexist as environmental contaminants. The aims of this study were to evaluate the transformation of 100 mg L of TNT, 2,4-DNT, and PETN by Raoultella planticola M30b and Rhizobium radiobacter M109c and identify enzymes that may participate in the transformation.

Effect of hydraulic retention time on microbial community in biochemical passive reactors during treatment of acid mine drainage.

The effect of hydraulic retention time (HRT) on the microbial community during acid mine drainage (AMD) treatment was investigated. Physicochemical and molecular (illumina and qPCR) analyses were performed on reactive mixtures collected from seven bioreactors in three-operation period (8, 17 and 36weeks). Long HRT (4day) favored the relative abundance of SRB, causing the increase of residual sulfides and short HRT (1day) affected the anaerobic conditions of the bioreactors and favored the presence the acidophilic chemolithotrophic microorganisms.

Biochemical passive reactors for treatment of acid mine drainage: Effect of hydraulic retention time on changes in efficiency, composition of reactive mixture, and microbial activity.

Biochemical passive treatment represents a promising option for the remediation of acid mine drainage. This study determined the effect of three hydraulic retention times (1, 2, and 4 days) on changes in system efficiency, reactive mixture, and microbial activity in bioreactors under upward flow conditions. Bioreactors were sacrificed in the weeks 8, 17 and 36, and the reactive mixture was sampled at the bottom, middle, and top layers.

Persistence of pentolite (PETN and TNT) in soil microcosms and microbial enrichment cultures.

Pentolite is a mixture (1:1) of 2,4,6-trinitrotoluene (TNT) and pentaerythritol tetranitrate (PETN), and little is known about its fate in the environment. This study was aimed to determine the dissipation of pentolite in soils under laboratory conditions. Microcosm experiments conducted with two soils demonstrated that dissipation rate of PETN was significantly slower than that of TNT.

Prevalence of the gene trzN and biogeographic patterns among atrazine-degrading bacteria isolated from 13 Colombian agricultural soils.

The following study evaluated the diversity and biogeography of 83 new atrazine-degrading bacteria and the composition of their atrazine degradation genes. These strains were isolated from 13 agricultural soils and grouped according to rep-PCR genomic fingerprinting into 11 major clusters, which showed biogeographic patterns. Three clusters (54 strains) belonged to the genus Arthrobacter, seven clusters (28 strains) were similar to the genus Nocardioides and only one strain was a gram-negative from the genus Ancylobacter.

Improved purification and PCR amplification of DNA from environmental samples.

Purification and PCR amplification procedures for DNA extracted from environmental samples (soil, compost, and river sediment) were improved by introducing three modifications: precipitation of DNA with 5% polyethylene glycol 8000 (PEG) and 0.6 M NaCl; filtration with a Sepharose 4B-polyvinylpolypyrrolidone (PVPP) spin column; and addition of skim milk (0.3% w/v) to the PCR reaction solution.

Treatment of high-strength dairy wastewater in an anaerobic deep reservoir: analysis of the methanogenic fermentation pathway and the rate-limiting step.

The wastewater of the largest dairy factory in Israel (Tnuva, Tel-Yosef), discharging approximately 6000 tons BOD per year, is treated in two serial, deep reservoirs (anaerobic/facultative). In this study, which focused on the anaerobic reservoir, we combined in situ measurements (over 18 months) and supporting lab experiments, in order to evaluate its efficiency and to identify the rate-limiting step of the methanogenic fermentation pathway. The anaerobic reservoir could remove above 75% of the BOD and COD all year round, but this was not enough to prevent malodors during the winter.

Reductive dehalogenation of tetrabromobisphenol-A by sediment from a contaminated ephemeral streambed and an enrichment culture.

This study was aimed at improving our understanding of the physiology of the microorganisms that reductively dehalogenate tetrabromobisphenol-A (TBBPA). Activity was followed in contaminated sediments from a polluted streambed as well as from fracture filling material underlying the stream. Reductive dehalogenation was observed in surface sediments but not in fracture filling samples from a depth of 3m.

Enrichment of a microbial culture capable of reductive debromination of the flame retardant tetrabromobisphenol-A, and identification of the intermediate metabolites produced in the process.

Tetrabromobisphenol-A is a reactive flame retardant used in the production of many plastic polymers. In previous research, it was demonstrated that anaerobic microorganisms from contaminated sediment debrominate tetrabromobisphenol-A to bisphenol-A, but an enrichment culture was not established. The current study was carried out to identify the intermediate metabolites in this process and to determine the factors facilitating enrichment of debrominating microorganisms.

Metabolism of diphenylurea by a Marinobacter sp. isolated from a contaminated ephemeral stream bed in the Negev Desert.

A moderate halophilic Marinobacter sp. (designated strain DPUZ) able to metabolize 1,3-diphenylurea (DPU) was isolated from a contaminated ephemeral desert stream bed near an industrial complex in the northern part of the Negev Desert (Israel). Metabolism of DPU was accompanied by a transient accumulation of a metabolite identified as aniline using gas chromatography-mass spectrometry, thus indicating a metabolic pathway involving cleavage of the urea bridge between the phenyl structures.