Pharmaceutical and personal care products (PPCPs) discharged with wastewater treatment plant (WWTP) effluents are an emerging surface water quality concern. Biological transformation has been identified as an important removal mechanism during wastewater treatment. The aim of this research was the identification of bacteria with characteristics for potential bioaugmentation to enhance PPCP removal. We report here the cultivation and characterization of bacteria capable of degrading PPCPs to ng/L concentrations. An isolation approach was developed using serial enrichment in mineral medium containing 1 mg/L of an individual PPCP as the sole organic carbon source available to heterotrophs until the original activated sludge inocula was diluted to ~10(-8) of its initial concentration, followed by colony growth on solid R2A agar. Eleven bacteria were isolated, eight that could remove triclosan, bisphenol A, ibuprofen, or 17β-estradiol to below 10 ng/L, one that could remove gemfibrozil to below 60 ng/L, and two that could remove triclosan or E2, but not to ng/L concentrations. Most bacterial isolates degraded contaminants during early growth when grown utilizing rich carbon sources and were only able to degrade the PPCPs on which they were isolated. Seven of the bacterial isolates were sphingomonads, including all the triclosan and bisphenol A degraders and the ibuprofen degrader. The study results indicate that the isolated bacteria may have a positive influence on removal in WWTPs if present at sufficient concentrations and may be useful for bioaugmentation.

Diversity, habitat range, and activities of sulfate-reducing prokaryotes within hot springs in Yellowstone National Park were characterized using endogenous activity measurements, molecular characterization, and enrichment. Five major phylogenetic groups were identified using PCR amplification of the dissimilatory sulfite reductase genes (dsrAB) from springs demonstrating significant sulfate reduction rates, including a warm, acidic (pH 2.5) stream and several nearly neutral hot springs with temperatures reaching 89°C. Three of these sequence groups were unrelated to named lineages, suggesting that the diversity and habitat range of sulfate-reducing prokaryotes exceeds that now represented in culture.Sulfate-reducing prokaryotes (SRP) are widely distributed in the environment. Their habitat range includes freshwater, marine, and hypersaline aquatic systems, cold oceanic sediments, the deep subsurface, hydrothermal vents, and hot springs (7,13,14,21,22,24). Although cultivated SRP are phylogenetically and physiologically diverse, they are restricted to four divisions within the Bacteria and one within the Archaea (25). Over 90% of described species are affiliated with the delta subdivision of the Proteobacteria (ca. 14 genera and 50 species) or the Fermicutes (Desulfotomaculum spp.). Those few that do not associate with these two divisions are affiliated with the thermophilic bacterial genera Thermodesulfobacterium and Thermodesulfovibrio or a single archaeal genus, Archaeoglobus. We now know their natural diversity is much greater than represented in culture, as revealed by endogenous activity measurements and more recent use of explicit molecular criteria (4-6, 8, 9, 17, 19). The report of sulfate respiration at 110°C in hydrothermal marine sediments is well beyond the maximum growth temperature of any isolate (16). Direct environmental surveys based on comparative sequencing of genes encoding the dissimilatory sulfite reductase (dsrAB) enzyme have identified novel clades in different environments, including a hypersaline microbial mat community, a uranium tailing site, a coastal fjord, and a hydrothermal vent worm (5,6,17,19).A more complete census of the environmental diversity of SRP has considerable importance for resolving their varied environmental roles, not necessarily restricted to sulfate reduction, and developing a better understanding of their origins and evolution. Since the genes in the pathway for sulfate respiration are sufficiently conserved to be recovered by PCR amplification, and since virtually all recognized genera have been characterized by comparative sequencing of genes encoding the 16S rRNA and the dissimilatory sulfite reductase (dsrAB) (18), these sequences now provide a framework to explicitly identify environmental populations. In the present study, we used a threefold approach, incorporating endogenous activity measurements, molecular characterization, and enrichment to characterize the diversity and activity of SRP in various thermal springs in Yellowstone National Park, Wyo.Site...

[1] Little is known about the long-term impacts of metal contamination on the microbiota of anoxic lake sediments. In this study, we examined microbial biomass and metals (arsenic, cadmium, chromium, copper, iron, lead, manganese, and zinc) in the sediments of Lake DePue, a backwater lake located near a former zinc smelter. Sediment core samples were examined using two independent measures for microbial biomass (total microscopic counts and total phospholipid phosphate concentrations) and for various fractions of each metal (pore water extracts, sequential extractions, and total extracts of all studied metals and zinc speciation by X-ray absorption fine structure). Zinc concentrations were up to 1000 times higher than reported for sediments in the adjacent Illinois River and ranged from 21,400 mg/kg near the source to 1,680 mg/kg near the river. However, solid metal fractions were not well correlated with pore water concentrations and were not good predictors of biomass concentrations. Instead, biomass, which varied among sites by as much as 2 times, was inversely correlated with concentrations of pore water zinc and arsenic as established by multiple linear regression. Monitoring of other parameters known to naturally influence biomass in sediments (e.g., organic carbon concentrations, nitrogen concentrations, pH, sediment texture, and macrophytes) revealed no differences that could explain observed biomass trends. This study provides strong support for control of microbial abundance by pore water metal concentrations in contaminated freshwater sediments.

Contamination, such as by heavy metals, has frequently been implicated in altering microbial community structure. However, this association has not been extensively studied for anaerobic communities, or in freshwater lake sediments. We investigated microbial community structure in the metal-contaminated anoxic sediments of a eutrophic lake that were impacted over the course of 80 years by nearby zinc-smelting activities. Microbial community structure was inferred for bacterial, archaeal and eukaryotic populations by evaluating terminal restriction fragment length polymorphism (TRFLP) patterns in near-surface sediments collected in triplicate from five areas of the lake that had differing levels of metal contamination. The majority of the fragments in the bacterial and eukaryotic profiles showed no evidence of variation in association with metal contamination levels, and diversity revealed by these profiles remained consistent even as metal concentrations varied from 3000 to 27 000 mg kg À1 total Zn, 0.125 to 11.2 lM pore water Zn and 0.023 to 5.40 lM pore water As. Although most archaeal fragments also showed no evidence of variation, the prevalence of a fragment associated with mesophilic Crenarchaeota showed significant positive correlation with total Zn concentrations. This Crenarchaeota fragment dominated the archaeal TRFLP profiles, representing between 35% and 79% of the total measured peak areas. Lake DePue 16S rRNA gene sequences corresponding to this TRFLP fragment clustered with anaerobic and soil mesophilic Crenarchaeota sequences. Although Crenarchaeota have been associated with metal-contaminated groundwater and soils, this is a first report (to our knowledge) documenting potential increased prevalence of Crenarchaeota associated with elevated levels of metal contamination.