- Monterotondo, Italy
The diversity of filamentous bacteria present in industrial wastewater treatment plants was analysed by a combination of classical and molecular-biological approaches. Many unknown filamentous bacteria were observed in about 80 screened... more
The diversity of filamentous bacteria present in industrial wastewater treatment plants was analysed by a combination of classical and molecular-biological approaches. Many unknown filamentous bacteria were observed in about 80 screened activated sludge samples from different industries with sometimes severe bulking sludge problems. A special focus was paid to filaments which resembled "Nostocoida limicola", a filamentous bacterium which was found to be present in many WWTPs. These filamentous bacteria are hardly cultivable and only one strain was obtained and maintained in co-culture with a yeast. The 16S rRNA sequences of several other "Nostocoida limicola"-like filamentous bacteria from different sludge samples were obtained by micromanipulation and different molecular-biological methods. The sequences were phylogenetically analyzed and specific molecular probes were developed and applied. The results clearly demonstrate that "Nostocoida limicola"-li...
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Solutions to global water stress problems are urgently needed yet must be sustainable, economical and safe. The utilisation of alternative water sources like reclaimed municipal wastewater is one of the most obvious and promising options... more
Solutions to global water stress problems are urgently needed yet must be sustainable, economical and safe. The utilisation of alternative water sources like reclaimed municipal wastewater is one of the most obvious and promising options in integrated water resources management. Among the various beneficial uses of reclaimed wastewater Managed aquifer recharge (MAR) receives growing attention because it features advantages such as additional natural treatment, storage capacity to buffer seasonal variations of supply and demand as well as mixing with natural water bodies which promotes the acceptance of further uses, particularly indirect potable use. Major concerns about the safety of this exploitation route of an alternative water source are connected to microbial and chemical contaminants occurring in wastewater, among which are emerging trace organics like endocrine disrupters and pharmaceuticals. This paper presents the European RECLAIM WATER research project on safe water recla...
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Batch bench-scale tests under strictly controlled conditions were carried out to evaluate nitrate and nitrite reduction kinetics. For nitrate reduction, the concentrations of limiting substrates have been characterized: the rate of... more
Batch bench-scale tests under strictly controlled conditions were carried out to evaluate nitrate and nitrite reduction kinetics. For nitrate reduction, the concentrations of limiting substrates have been characterized: the rate of nitrate reduction with methanol was found to be limited when the concentration of organic carbon goes below 40 mg chemical oxygen demand (COD)/l, whereas under noncarbon limiting conditions denitrification kinetics were seen to be zero-order even at low nitrate concentrations (<1 mg N/l). As for nitrite reduction, tests show that the nitrogenous substrate itself markedly inhibits denitrification-probably because of the presence of free nitrous acid. That biomass inhibition does not necessarily occur if nitrite concentrations higher than threshold values are reached gradually shows that denitrifying biomass may acclimatize to nitrites.
Denitrification kinetics parameters are evaluated for a phenol carbon source. Batch and continuous anoxic‐aerobic lab‐scale plant test results are compared.
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This paper describes a theoretical and experimental approach to evaluating nitrification inhibition (types and degrees) by some substances to be found in coke plant discharges.
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Biological nutrient removal (BNR) systems across the globe frequently experience bulking and foaming episodes, which present operational challenges such as poor sludge settling due to excessive filamentous bacteria. A full-scale BNR plant... more
Biological nutrient removal (BNR) systems across the globe frequently experience bulking and foaming episodes, which present operational challenges such as poor sludge settling due to excessive filamentous bacteria. A full-scale BNR plant treating primarily domestic wastewater was monitored over a period of 1 year to investigate filamentous bacterial growth response under various plant operating parameters. Identification of filamentous bacteria by conventional microscopy and fluorescent in situ hybridisation indicated the dominance of Eikelboom Type021N, Thiothrix spp., Eikelboom Type 1851 and Eikelboom Type 0092. A cumulative logit model (CLM) was applied to elucidate significant relationships between the filamentous bacteria and plant operational parameters. The model could predict the potential abundance of dominant filamentous bacteria in relation to wastewater treatment plant operational parameters. Data obtained from the model corroborated with previous findings on the dominance of most filaments identified, except for Type 0092, which exhibited some unique traits. With further validation, the model could be successfully applied for identifying specific parameters which could contribute towards filamentous bulking, thus, providing a useful tool for regulating specific filamentous growth in full-scale wastewater treatment plants.
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Two microbial cultures able to degrade high concentrations of VC as the sole carbon source have been obtained by enrichment from activated sludge. The cultures began consuming VC (0.02 mmol l(-1)) only after a long initial acclimation... more
Two microbial cultures able to degrade high concentrations of VC as the sole carbon source have been obtained by enrichment from activated sludge. The cultures began consuming VC (0.02 mmol l(-1)) only after a long initial acclimation period (1-2 months). After then the concentration of VC was gradually increased (from 0.02 to 0.8 mmol l(-1)) and the cultures were able to maintain VC degrading ability for long time (over 500 days). VC-degrading biomass in the two cultures was characterized by low specific maximum growth rates (0.19-0.21 d(-1)) compared to heterotrophic organisms typically present in activated sludge processes. Monod half-saturation constant was rather low (0.7-1.6 mg VC l(-1)) indicating that it is possible to effectively remove VC to low residual concentrations. The cultures were highly sensitive to even short periods of VC lack (with quick decrease of VC degradation rates) whereas they were not to sudden load increases (up to 3.4 mmol l(-1)). After being cultured ...
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An anaerobic consortium taken from brackish sediments, enriched by PCE/CH3OH sequential feeding, was capable of completely dechlorinating tetrachloroethene (PCE) to ethene (ETH). In batch experiments, PCE (0.5 mM) was dechlorinated to... more
An anaerobic consortium taken from brackish sediments, enriched by PCE/CH3OH sequential feeding, was capable of completely dechlorinating tetrachloroethene (PCE) to ethene (ETH). In batch experiments, PCE (0.5 mM) was dechlorinated to ethene (ETH) in approximately 75 h with either CH3OH or H2 as the electron donor. When VC (0.5 mM) was added instead of PCE it was dechlorinated without any initial lag by the PCE/CH3OH enriched consortium, although at a lower dechlorination rate. In batch tests H2 could readily replace CH3OH for supporting PCE dechlorination, with a similar PCE dechlorination rate and product distribution with respect to those observed with methanol. This indicates that H2 production during CH3OH fermentation was not the rate-limiting step of PCE or VC dechlorination. Acetogenesis was the predominant activity when methanol was present. A remarkable homoacetogenic activity was also observed when hydrogen was supplied instead of methanol.
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The diversity of filamentous bacteria present in industrial wastewater treatment plants was analysed by a combination of classical and molecular-biological approaches. Many unknown filamentous bacteria were observed in about 80 screened... more
The diversity of filamentous bacteria present in industrial wastewater treatment plants was analysed by a combination of classical and molecular-biological approaches. Many unknown filamentous bacteria were observed in about 80 screened activated sludge samples from different industries with sometimes severe bulking sludge problems. A special focus was paid to filaments which resembled "Nostocoida limicola", a filamentous bacterium which was found to be present in many WWTPs. These filamentous bacteria are hardly cultivable and only one strain was obtained and maintained in co-culture with a yeast. The 16S rRNA sequences of several other "Nostocoida limicola"-like filamentous bacteria from different sludge samples were obtained by micromanipulation and different molecular-biological methods. The sequences were phylogenetically analyzed and specific molecular probes were developed and applied. The results clearly demonstrate that "Nostocoida limicola"-li...
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An activated sludge was cultivated on a mixture of several soluble substrates (acetate, ethanol, glucose, glutamic acid, peptone, Tween 80, starch, yeast extract) in an anoxic/aerobic SBR. Highly dynamic conditions in the SBR (feast... more
An activated sludge was cultivated on a mixture of several soluble substrates (acetate, ethanol, glucose, glutamic acid, peptone, Tween 80, starch, yeast extract) in an anoxic/aerobic SBR. Highly dynamic conditions in the SBR (feast famine regime) caused fast removal of most COD in the anoxic phase (in particular acetate, ethanol, glutamic acid and glucose were totally removed) and relevant contribution of storage. In spite of that, filament abundance was always high, as is typical of bulking sludges. Filaments which developed in the reactor were characterized on a morphological basis and on the basis of their ability to grow and to store polyhydroxyalkanoates (PHAs). Three main filaments prevailed in the biocenosis, whose relative abundance was varyng with time: Nostocoida limicola II, (two different morphological types), Haliscomenobacter hydrossis and an unidentified one. It was found that maximum growth rate was higher for flocformers than for filaments on each of the tested sub...
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We have been studying an anaerobic enrichment culture which, by using methanol as an electron donor, dechlorinates tetrachloroethene (PCE) to vinyl chloride and ethene. Our previous results indicated that H2 was the direct electron donor... more
We have been studying an anaerobic enrichment culture which, by using methanol as an electron donor, dechlorinates tetrachloroethene (PCE) to vinyl chloride and ethene. Our previous results indicated that H2 was the direct electron donor for rductive dechlorination of PCE by the methanol-PCE culture. Most-probable-number counts performed on this culture indicated low numbers (< or equal to 10(4)/ml)) of methanogens and PCE dechlorinators using methanol and high numbers (> or equal to 10(6)/ml)) of sulfidogens, methanol-utilizing acetogens, fermentative heterotrophs, and PCE dechlorinators using H2. An anaerobic H2-PCE enrichment culture was derived from a 10(-6) dilution of the methanol-PCE culture. This H2-PCE culture used PCE at increasing rates over time when transferred to fresh medium and could be transferred indefinitely with H2 as the electron donor for the PCE dechlorination, indicating that H2-PCE can serve as an electron donor-acceptor pair for energy conservation an...
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We investigated the bacterial community compositions and phosphorus removal performance under sludge bulking and non-bulking conditions in two biological wastewater treatment systems (conventional A²/O (anaerobic/anoxic/aerobic) and... more
We investigated the bacterial community compositions and phosphorus removal performance under sludge bulking and non-bulking conditions in two biological wastewater treatment systems (conventional A²/O (anaerobic/anoxic/aerobic) and inverted A²/O (anoxic/anaerobic/aerobic) processes) receiving the same raw wastewater. Sludge bulking resulted in significant shift in bacterial compositions from Proteobacteria dominance to Actinobacteria dominance, characterized by the significant presence of filamentous 'Candidatus Microthrix parvicella'. Quantitative real-time polymerase chain reaction (PCR) analysis revealed that the relative abundance of 'Candidatus Accumulibacter phosphatis', a key polyphosphate-accumulating organism responsible for phosphorus removal, with respect to 16s rRNA genes of total bacteria was 0.8 and 0.7%, respectively, for the conventional and inverted A²/O systems when sludge bulking occurred, which increased to 8.2 and 12.3% during the non-bulking pe...
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Solutions to global water stress problems are urgently needed yet must be sustainable, economical and safe. The utilisation of alternative water sources like reclaimed municipal wastewater is one of the most obvious and promising options... more
Solutions to global water stress problems are urgently needed yet must be sustainable, economical and safe. The utilisation of alternative water sources like reclaimed municipal wastewater is one of the most obvious and promising options in integrated water resources management. Among the various beneficial uses of reclaimed wastewater Managed aquifer recharge (MAR) receives growing attention because it features advantages such as additional natural treatment, storage capacity to buffer seasonal variations of supply and demand as well as mixing with natural water bodies which promotes the acceptance of further uses, particularly indirect potable use. Major concerns about the safety of this exploitation route of an alternative water source are connected to microbial and chemical contaminants occurring in wastewater, among which are emerging trace organics like endocrine disrupters and pharmaceuticals. This paper presents the European RECLAIM WATER research project on safe water recla...
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A pure culture of Amaricoccus kaplicensis was aerobically cultured at a long culture residence time (Theta(C)&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;12d), under periodic acetate feeding in a sequencing... more
A pure culture of Amaricoccus kaplicensis was aerobically cultured at a long culture residence time (Theta(C)&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;12d), under periodic acetate feeding in a sequencing batch reactor (SBR). The cycle length and, correspondingly, the volumetric organic load rate (vOLR) were varied in the range 4-24h and 0.76-0.12gCODl(-1)d(-1), respectively. The transient response of the microorganism to the acetate spike was investigated throughout batch tests, as a function of SBR cycle length and vOLR. In all tested conditions, a rapid transient response was observed, mainly due to acetate storage in the form of polyhydroxybutyrate, since growth (production of active biomass) played a minor role. Apart from this general trend, the maximum rates under transient conditions increased as the cycle length increased from 4 to 24h. In the SBR, the longest cycle also caused a decrease in floc size and settleability as well as an increase in the observed yield. The observed effect of SBR operating conditions on the physiological state of cells and their related transient response may have great significance on the performance of full scale activated sludge processes.
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Salmonella is one of the leading causes of intestinal illness all over the world as well as the etiological agent of more severe systemic diseases such as typhoid and paratyphoid fevers. While water is known to be a common vehicle for the... more
Salmonella is one of the leading causes of intestinal illness all over the world as well as the etiological agent of more severe systemic diseases such as typhoid and paratyphoid fevers. While water is known to be a common vehicle for the transmission of typhoidal Salmonella serovars, non-typhoidal salmonellae are mainly known as foodborne pathogens. This paper provides a brief review of the last ten years of peer reviewed publications on the prevalence of Salmonella in natural freshwaters and drinking waters, and on the relevance of these sources for Salmonella dissemination. In industrialized countries, Salmonella was rarely reported in water-borne outbreaks despite it being frequently detected in surface waters including recreational waters and waters used for irrigation or as a drinking water source. Consistent contamination with irrigation waters has been shown to be a common route of crop contamination in produces related Salmonella outbreaks. Multiple drug resistant (MDR) Sal...
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A strain of broad-spectrum, mercury-resistant Pseudomonas putida FB1 was used to remove mercury as the gaseous element (Hg(0)) from a continuous axenic culture, fed with a synthetic medium containing 1 mg Hg l(-1) as HgCl2. Mercury... more
A strain of broad-spectrum, mercury-resistant Pseudomonas putida FB1 was used to remove mercury as the gaseous element (Hg(0)) from a continuous axenic culture, fed with a synthetic medium containing 1 mg Hg l(-1) as HgCl2. Mercury determinations were performed in steady-state cultures using various culture fractions [whole culture, filtered supernatant, bacterial cells (dry wt), recovery trap liquid] in order to determine the removal efficiency at different dilution rates (from 0.1 to 3.0 day(-1)). The removal efficiency ranged from 99.2% to 99.8%, and the residual Hg was maintained below 5 μ l(-1) (the maximum allowable concentration of Hg in liquid wastes according to Italian law) at a dilution rate of 1.0 day(-1), corresponding to a Hg flux of 40 μg l(-1) h(-1). Hg accumulation by cell biomass was negligible for dilution rates under 1.0 day(-1). A progressive accumulation of Hg, both in the liquid phase and in cells, occurred at a higher dilution rate (3.0 day(-1); close to washout), corresponding to a Hg concentration of 25 μg g(-1) (dry wt). The estimated Km and Vmax for Hg reduction were 0.241 mg l(-1) and 9.5 mg g(-1) h(-1), respectively. In batch experiments maximum Hg removal occurred at the optimum growth temperature (28°C) of P. putida. The maximum recovery of Hg in the liquid trap was 78%.
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ABSTRACT This is the first study that investigates in detail the effect of different sulfate concentrations on trichloroethene-dechlorinating microbial communities, both in terms of dechlorinating performance and microbial composition.... more
ABSTRACT This is the first study that investigates in detail the effect of different sulfate concentrations on trichloroethene-dechlorinating microbial communities, both in terms of dechlorinating performance and microbial composition. The study used a series of Dehalococcoides-containing trichloroethene-dechlorinating microbial communities, which operated for more than 800 days in the presence of different sulfate concentrations and limiting-electron donor conditions. This study proves the ability of Dehalococcoides spp., the only genus able to completely dechlorinate trichloroethene, to predominate in mixed anaerobic microbial communities regardless of the magnitude of sulfate concentration, even under limiting-electron donor conditions. Although other microorganisms, such as the Sulfurospirillum spp. bacteria and members of the sulfate-reducing bacteria group were able to thrive, they were not able to predominate in such a competitive environment. However, this picture was not reflected in reductive dechlorination, which demonstrated a much better performance under methanogenic conditions or in the presence of low sulfate concentration (30 mg/l) than in the presence of higher sulfate concentrations (&gt;400 mg/l). Therefore, different species of Dehalococcoides or other dechlorinating bacteria, which are not able to thrive in the presence of high sulfate concentrations (&gt;400 mg/l), are possibly responsible for the higher dechlorination efficiency that was observed under methanogenic conditions.
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ABSTRACT In various activated sludge systems, sludge grows under transient (unbalanced) conditions and storage of internal polymers becomes important. Differences in storage capacity under transients are often used to explain kinetic... more
ABSTRACT In various activated sludge systems, sludge grows under transient (unbalanced) conditions and storage of internal polymers becomes important. Differences in storage capacity under transients are often used to explain kinetic control of bulking, but storage is neither studied in detail nor usually included in modelling. For this reason, the transient response of different aerobic mixed cultures was studied by experimentally determining the role of storage. Two different mixed cultures (bulking and non-bulking) were selected in an acetate-limited medium, by continuous or intermittent feeding of a CSTR, respectively. Batch tests were used to investigate the transient response of the selected cultures as a function of the starvation time and of the ratio of the initial concentration of the substrate and sludge biomass (So/Xo). In most experimental conditions, both cultures showed that the storage of poly-bydroxybutyrate (PHB) is in general the prevailing mechanism of substrate removal. In particular, the culture dominated by floc-formers showed very fast response to the substrate spike with a high observed yield. Storage was practically the only metabolism occurring. The ratio So/Xo did not have a major role in determining the type and extent of the response. Starvation did not affect the response of the floc-formers to transient conditions. For the filamentous bacteria, both the growth response and, even more significantly, the storage response were negatively affected. Hence, the difference in storage capacity between filamentous and floc-forming bacteria was further increased.
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Activated sludge was submitted to aerobic dynamic substrate feeding for the production of biodegradable plastics. Two sequencing batch reactors were operated with acetate or propionate as sole carbon substrates. With acetate a homopolymer... more
Activated sludge was submitted to aerobic dynamic substrate feeding for the production of biodegradable plastics. Two sequencing batch reactors were operated with acetate or propionate as sole carbon substrates. With acetate a homopolymer of polyhydroxybutyrate (PHB) was obtained and with propionate a copolymer of hydroxybutyrate and hydroxyvalerate P(HB/HV) was produced. Three main morphotypes were identified in both sludges: two belong to the Alphaproteobacteria class and the third to the Betaproteobacteria class. Bacilli belonging to Betaproteobacteria were shown by FISH analysis, applied in combination with Nile Blue post-staining, to be the main responsible for PHAs storage. The latter were affiliated to Azoarcus genus within Betaproteobacteria.
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Microthrir parvicella strain RN1, isolated by micromanipulation from an activated sludge treatment plant in Italy, is phylogenetically identical to two other isolates from Australia. Our Italian isolate of M. parvicella is a slow... more
Microthrir parvicella strain RN1, isolated by micromanipulation from an activated sludge treatment plant in Italy, is phylogenetically identical to two other isolates from Australia. Our Italian isolate of M. parvicella is a slow growing (μmax ranging from 0.3 to 0.5 d-1), ...
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... Bayly RC, Duncan A., May JW, Schembri M., Semertjis A., Vasiliadis G. and Rape WGC (1990b) Microbio-logical and genetic aspects of the synthesis of polyphos-phate by species ... Presented at 61st Annual Conference of the Water... more
... Bayly RC, Duncan A., May JW, Schembri M., Semertjis A., Vasiliadis G. and Rape WGC (1990b) Microbio-logical and genetic aspects of the synthesis of polyphos-phate by species ... Presented at 61st Annual Conference of the Water Pollution Control Federation, Dallas, Tex., pp ...
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A pure culture of Thiothrix strain CT3 has been aerobically cultured under periodic acetate feeding in a Sequencing Batch Reactor (SBR) at volumetric organic load rate of 0.12gCODL(-1)d(-1). Two different culture residence times (12d or... more
A pure culture of Thiothrix strain CT3 has been aerobically cultured under periodic acetate feeding in a Sequencing Batch Reactor (SBR) at volumetric organic load rate of 0.12gCODL(-1)d(-1). Two different culture residence times (12d or 20d) were adopted as well as two different feed frequencies (1 and 4d(-1), for each culture residence time), the volumetric organic load rate being the same under all conditions. The transient response of the microorganism to the periodic acetate feed was investigated through batch tests with biomass withdrawn from the SBR, as function of the different SBR operating conditions. In all tested conditions, a quick transient response to the acetate spike was observed with fast increase of acetate uptake rate (ranging from 71 to 247mgCODgCOD(-1)h(-1)). This transient response was mainly due to acetate storage in form of poly-hydroxybutyrate (ranging from 45% to 64% of the observed yield) whereas the growth response (i.e. increase of production rate of active biomass) generally played a minor role (ranging from 21% to 38% of the observed yield). Apart from this general trend, culture residence time as well as feed frequency had a strong impact on transient behaviour of cultured cells. The overall transient response (i.e. maximum specific substrate removal rate) increased as culture residence time decreased or as feed frequency increased. Moreover, the ratio of storage response and growth response increased as the overall transient response decreased, i.e. the storage response was preferentially maintained when cells presented a lower transient response. The ability of the cells to increase their growth rate with respect to SBR average value was the lowest under the most unfavourable conditions (residence time 20d, feed frequency 1d(-1)) and increased with the increase in maximum substrate uptake rate.
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The presence of a specialized physiological group, the so-called poly-P bacteria, in activated sludge has been proposed to explain the uptake of organic carbon sources under anaerobic conditions and the cyclic release and uptake of... more
The presence of a specialized physiological group, the so-called poly-P bacteria, in activated sludge has been proposed to explain the uptake of organic carbon sources under anaerobic conditions and the cyclic release and uptake of phosphate in activated-sludge ...
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Research Interests: Water quality, Environmental Monitoring, Water Reuse, Multidisciplinary, Water Supply, and 17 moreEurope, Escherichia coli, Campylobacter, Animals, Seasonal variation, Salmonella, Drinking Water Quality, Enterococcus, Fresh water, Cryptosporidium, Water Quality, Water Microbiology, Helminths, Clostridium, Water Storage, Giardia, and Salmonella spp.
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In this study two different microbial cultures (one constructed with lagoon sediments from an industrial area in Venice, Italy and the other with aquifer material from a chlorinated solvent-contaminated site in Rho, Italy) were... more
In this study two different microbial cultures (one constructed with lagoon sediments from an industrial area in Venice, Italy and the other with aquifer material from a chlorinated solvent-contaminated site in Rho, Italy) were investigated for their ability to dechlorinate perchloroethylene (PCE), 1,1,2,2-tetrachloroethane (TeCA) and their mixtures with butyrate as the primary electron donor (i.e., the H2-releasing substrate) in the
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Nowadays several advanced molecular techniques are applied for quantifying bacteria involved in contaminant degradation processes. However, despite the fact that significant efforts have been taken to make these tools more reliable and... more
Nowadays several advanced molecular techniques are applied for quantifying bacteria involved in contaminant degradation processes. However, despite the fact that significant efforts have been taken to make these tools more reliable and specific, their application for the analysis of field samples is hardly ever applied. In this study, a combination of three methods (CARD-FISH, qPCR and RT-qPCR) was successfully applied to evaluate the distribution and the activity of known chlorinated solvent dechlorinating bacteria in a contaminated site where no remedial actions have been undertaken. CAtalysed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) specifically provided the cell densities of known dechlorinating bacteria and was found to be more sensitive than quantitative PCR (qPCR) for the quantification of &#39;Dehalococcoides&#39; cell numbers in the aquifer. Among the screened dechlorinators, &#39;Dehalococcoides&#39; spp. were mainly found and nearly homogenously distributed in the aquifers at concentrations ranging from 8.1×10(5)±1.2×10(5) to 2.5×10(7)±5.6×10(6)cells per liter of groundwater (with a relative abundance out of the total Bacteria of 0.7-15%). Further, the dechlorination potentialities of &#39;Dehalococcoides&#39; species living in the aquifer were evaluated by analyzing the abundance and the expression of 16S rRNA genes and reductive dehalogenase (RDase) encoding functional genes by qPCR and Reverse Transcription qPCR (RT-qPCR). &#39;Dehalococcoides&#39;tceA gene, known to be associated to strains capable of reducing chlorinated solvents beyond cis-DCE, was found and expressed in the field. Overall, this study proved the existence of a well-established dechlorinating microbial community able to use contaminants as substrates for their metabolic activity and indicated the occurrence of reductive dechlorination at the site.
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A mixed culture capable of dechlorinating perchloroethylene (PCE) to ethene was analyzed under non steady and pseudo-steady state conditions. Dehalococcoides mccartyi, considered to be the primary dechlorinating bacterium able to... more
A mixed culture capable of dechlorinating perchloroethylene (PCE) to ethene was analyzed under non steady and pseudo-steady state conditions. Dehalococcoides mccartyi, considered to be the primary dechlorinating bacterium able to completely degrade chlorinated hydrocarbons to non toxic ethene, could be detected by CAtalyzed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) since the beginning of culture operation but highlighted by conventional FISH only during active PCE dechlorination to ethene and vinyl chloride (VC). Data generated from FISH and CARD-FISH analyses were compared to those generated from applying PCR-based techniques directed at defining cell abundances (Real Time PCR, qPCR) and assessing cell activities (Reverse Transcription qPCR, RT-qPCR) of Dehalococcoides strains involved in the PCE reductive dechlorination (RD) process. qPCR targeting reductive dehalogenase genes coding for enzymes involved in the individual steps of the RD process, showed that Dehalococcoides strains carrying the tceA gene dominated the community. This observation was consistent with PCE conversion products detected under pseudo-steady state (ethene and VC production), since this tceA gene is known to be associated to strains capable of reducing chlorinated solvents beyond 1,2-cis-dichloroethene (cis-DCE). In line with the FISH data, Dehalococcoides 16S rRNA and tceA genes were expressed only during pseudo-steady state conditions when PCE was converted completely to the final metabolic product ethene. Furthermore, Dehalococcoides cell abundances estimated by CARD-FISH correlated positively with their 16SrRNA gene copy numbers quantified by qPCR. This is consistent with the ability of both these methods to estimate total Dehalococcoides cell numbers including those with low metabolic activities. Thus, this study shows that application potential of FISH analysis to quantify rapidly and efficiently only active dechlorinators in complex communities.
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Research Interests: Microbiology, Water Purification, Activated Sludge, Polymers, Multidisciplinary, and 17 moreEnzymes, Fatty acids, Ethanol, Nitrates, Amino Acids, Alphaproteobacteria, Ecosystem, Fluorescent in situ hybridization, Carbohydrate metabolism, Sewage, Control Strategy, Group, Industrial wastewater, Enzyme activity, Amino Acid Profile, Water Microbiology, and Nitrites
After 25 editions carried out , the course this year has a new venue and a new organizational structure. It has been recognized that it had the great merit of having contributed much to the spread of knowledge about the problems of... more
After 25 editions carried out , the course this year has a new venue and a new organizational structure. It has been recognized that it had the great merit of having contributed much to the spread of knowledge about the problems of dysfunctions of activated sludge plants, in Italy and also abroad. We hope to continue to ensure the quality of previous editions while addressing also new issues connected with the application of new and emerging treatment technologies. The Course is organized by DICAM University of Palermo, IRSA-CNR and ABP.it (www.unipa.it/26aspmico)
Dopo 25 edizioni svoltesi con successo, il Corso questo anno trova una nuova sede e una nuova struttura organizzativa. Al corso è stato riconosciuto il merito di avere contribuito molto alla diffusione della conoscenza sui problemi delle disfunzioni degli impianti di depurazione a fanghi attivi sia in Italia che all’estero. Contiamo di poter continuare ad assicurare la qualità delle precedenti edizioni pur affrontando nuovi temi connessi con l’applicazione di nuove tecnologie di depurazione emergenti. . Il Corso è organizzato daDICAM University of Palermo, IRSA-CNR and ABP.it (www.unipa.it/26aspmico)
Dopo 25 edizioni svoltesi con successo, il Corso questo anno trova una nuova sede e una nuova struttura organizzativa. Al corso è stato riconosciuto il merito di avere contribuito molto alla diffusione della conoscenza sui problemi delle disfunzioni degli impianti di depurazione a fanghi attivi sia in Italia che all’estero. Contiamo di poter continuare ad assicurare la qualità delle precedenti edizioni pur affrontando nuovi temi connessi con l’applicazione di nuove tecnologie di depurazione emergenti. . Il Corso è organizzato daDICAM University of Palermo, IRSA-CNR and ABP.it (www.unipa.it/26aspmico)