In the absence of sunlight energy, microbial community survival in subterranean aquifers depends on integrated mechanisms of energy and nutrient scavenging. Because karst aquifers are particularly sensitive to agricultural land use impacts due to rapid and direct hydrologic connections for pollutants to enter the groundwater, we examined the fate of an exogenous pesticide (atrazine) into such a...

because of the importance of microbial metabolites of cholesterol as precursors in the synthesis of steroidal drugs, we decided to study the ability of arthrobacter simplex to degrade cholesterol. arthrobacter simplex cleaves the side chain of cholesterol in the presence of 2,2'-dipyridyl and produces 4-androstene-3,17- dione (ad) and androsta- 1,4-diene-3,17-dione(add). two other intermed...

In order to examine the microbial degradation of p-nitrophenol (PNP) by a mixed culture system and simultaneous removal of nitrite released via the degradation, an activated sludge retained in porous carrier particles and a suspension culture as a control were acclimated to artificial sewage containing PNP as the sole carbon source. The adaptation of microbes retained in porous carrier particle...

We investigated the effects of various factors (brij 30, brij 35, yeast extract, hydrogen peroxide and compost) on the aerobic degradation of nonylphenol (NP) in soil and characterized the structure of the microbial community in that soil. Residues of NP were measured using gas chromatography-mass spectrometry (GC-MS) and a change of microbial communities was demonstrated using denaturing gradi...

Benzalkonium chlorides (BACs) are disinfectants widely used in a variety of clinical and environmental settings to prevent microbial infections, and they are frequently detected in nontarget environments, such as aquatic and engineered biological systems, even at toxic levels. Therefore, microbial degradation of BACs has important ramifications for alleviating disinfectant toxicity in nontarget...

[1] Molecular level characterizations of dissolved lignin were conducted in Mississippi River plume waters to study the impact of various removal mechanisms (photooxidation, microbial degradation, and flocculation) on dissolved organic material (DOM) concentrations and compositions. Prior to analysis, dissolved (<0.2-mm pore size) samples were size fractionated by ultrafiltration into high mole...

Bioremediation approaches for the treatment of oily sludge from a refinery were evaluated using a 2(3) factorial design. The three strategies tested were bioaugmentation with indigenous microbial consortia (MO) isolated from oily sludge, biostimulation with nutrients (NP) and biostimulation with the surfactant Triton X-100 (TX). Eight experimental runs were conducted in triplicate with factor s...

Introduction: Chlorpyrifos is an organophosphorus pesticide that is commonly used in agriculture. This toxin is harmful to a wide range of organisms, including living organisms, useful arthropods, fish, birds, humans, animals, and plants. There are many physical, chemical, and biological methods for the removal of organophosphorus pesticides from ecosystems, among which biodegradation is prefer...

The sorption of organic contaminants by natural organic matter (NOM) often limits substrate bioavailability and is an important factor affecting microbial degradation rates in soils and sediments. We hypothesized that reduced substrate bioavailability might influence which microbial assemblages are responsible for contaminant degradation under enrichment culture conditions. Our primary goal was...