Anoxic biodegradation of dimethyl phthalate (DMP) by activated sludge cultures under nitrate-reducing conditions

The process performance of an activated sludge system during acclimation to phthalate esters was examined. Concentration of the phthalate esters was increased gradually, and over about a two-week period, the acclimation to a mixture of 410 mg/L diethyl phthalate and 540 mg/L dimethyl phthalate was complete. It was observed that the effluent Chemical Oxygen Demand (COD) was not affected adversely in spite of increasing influent COD. Other indicators of process performance, for example, effluent suspended solids, were at acceptable levels at the completion of acclimation. The system responded well when 2,4-dinitrophenol, up to 4 mg/L, was included in the influent in addition to phthalate esters. Actually an improvement in system effluent COD was observed possibly due to increasing Mixed Liquor Suspended Solids (MLSS). At a 2,4-dinitrophenol concentration of 8 mg/L, system performance deteriorated considerably but the recovery was fast, and within a two-week period system performance returned to normal.

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Abundance and Phylogenetic Affiliation of Iron Reducers in Activated Sludge as Assessed by Fluorescence In Situ Hybridization and Microautoradiography

Applied and Environmental Microbiology ◽

10.1128/aem.68.9.4629-4636.2002 ◽

2002 ◽

Vol 68 (9) ◽

pp. 4629-4636 ◽

Cited By ~ 68

Author(s):

Jeppe Lund Nielsen ◽

Stefan Juretschko ◽

Michael Wagner ◽

Per Halkjær Nielsen

Keyword(s):

In Situ Hybridization ◽

Activated Sludge ◽

Fluorescence In Situ Hybridization ◽

Most Probable Number ◽

Probable Number ◽

Iron Reducing Bacteria ◽

Reducing Conditions ◽

Phylogenetic Affiliation ◽

Reducing Bacteria

ABSTRACT Microautoradiography (MAR) was used to enumerate acetate-consuming bacteria under Fe(III)-reducing conditions in activated sludge. This population is believed to consist of dissimilatory iron-reducing bacteria, because the applied incubation conditions and the use of specific inhibitors excluded consumption of radiolabeled acetate by other physiological groups such as sulfate reducers. By use of this approach, dissimilatory iron reducers were found in a concentration of 1.1 × 108 cells per ml, corresponding to approximately 3% of the total cell count as determined by DAPI (4′,6′-diamino-2-phenylindoledihydrochloride-dilactate) staining. The MAR enumeration method was compared to the traditional most-probable-number (MPN) method (FeOOH-MPN) and a modified MPN method, which contains Ferrozine directly within the MPN dilutions to determine the production of small amounts of ferrous iron (Ferrozine-MPN). The Ferrozine-MPN method yielded values 6 to 10 times higher than those obtained by the FeOOH-MPN method. Nevertheless, the MAR approach yielded counts that were 100 to 1,000 times higher than those obtained by the Ferrozine-MPN method. Specific in situ Fe(III) reduction rates per cell (enumerated by the MAR method) were calculated and found to be comparable to the respective rates for pure cultures of dissimilatory iron-reducing bacteria, suggesting that the new MAR method is most reliable. A combination of MAR and fluorescence in situ hybridization was used for phylogenetic characterization of the putative iron-reducing bacteria. All activated-sludge cells able to consume acetate under iron-reducing conditions were targeted by the bacterial oligonucleotide probe EUB338. Around 20% were identified as gamma Proteobacteria, and 10% were assigned to the delta subclass of Proteobacteria.

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Biodegradation of dimethyl phthalate, diethyl phthalate and di-n-butyl phthalate by Rhodococcus sp. L4 isolated from activated sludge

Journal of Hazardous Materials ◽

10.1016/j.jhazmat.2009.02.126 ◽

2009 ◽

Vol 168 (2-3) ◽

pp. 938-943 ◽

Cited By ~ 97

Author(s):

Yi Lu ◽

Fei Tang ◽

Ying Wang ◽

Jinhui Zhao ◽

Xin Zeng ◽

...

Keyword(s):

Activated Sludge ◽

Diethyl Phthalate ◽

Dimethyl Phthalate ◽

Butyl Phthalate ◽

Rhodococcus Sp

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Functional Characterization of PM6/13, a β3-specific (GPIIIa/CD61) Monoclonal Antibody that Shows Preferential Inhibition of Fibrinogen Binding over Fibronectin Binding to Activated Human Platelets

Thrombosis and Haemostasis ◽

10.1055/s-0037-1614247 ◽

1998 ◽

Vol 79 (01) ◽

pp. 177-185 ◽

Cited By ~ 10

Author(s):

Ashia Siddiqua ◽

Michael Wilkinson ◽

Vijay Kakkar ◽

Yatin Patel ◽

Salman Rahman ◽

...

Keyword(s):

Monoclonal Antibody ◽

Platelet Aggregation ◽

Platelet Rich Plasma ◽

Functional Characterization ◽

Human Platelets ◽

Western Blots ◽

Activated Platelets ◽

Reducing Conditions ◽

Fibronectin Binding

SummaryWe report the characterization of a monoclonal antibody (MAb) PM6/13 which recognises glycoprotein IIIa (GPIIIa) on platelet membranes and in functional studies inhibits platelet aggregation induced by all agonists examined. In platelet-rich plasma, inhibition of aggregation induced by ADP or low concentrations of collagen was accompanied by inhibition of 5-hydroxytryptamine secretion. EC50 values were 10 and 9 [H9262]g/ml antibody against ADP and collagen induced responses respectively. In washed platelets treated with the cyclooxygenase inhibitor, indomethacin, PM6/13 inhibited platelet aggregation induced by thrombin (0.2 U/ml), collagen (10 [H9262]g/ml) and U46619 (3 [H9262]M) with EC50 = 4, 8 and 4 [H9262]g/ml respectively, without affecting [14C]5-hydroxytryptamine secretion or [3H]arachidonate release in appropriately labelled cells. Studies in Fura 2-labelled platelets revealed that elevation of intracellular calcium by ADP, thrombin or U46619 was unaffected by PM6/13 suggesting that the epitope recognised by the antibody did not influence Ca2+ regulation. In agreement with the results from the platelet aggregation studies, PM6/13 was found to potently inhibit binding of 125I-fibrinogen to ADP activated platelets. Binding of this ligand was also inhibited by two other MAbs tested, namely SZ-21 (also to GPIIIa) and PM6/248 (to the GPIIb-IIIa complex). However when tested against binding of 125I-fibronectin to thrombin stimulated platelets, PM6/13 was ineffective in contrast with SZ-21 and PM6/248, that were both potent inhibitors. This suggested that the epitopes recognised by PM6/13 and SZ-21 on GPIIIa were distinct. Studies employing proteolytic dissection of 125I-labelled GPIIIa by trypsin followed by immunoprecipitation with PM6/13 and analysis by SDS-PAGE, revealed the presence of four fragments at 70, 55, 30 and 28 kDa. PM6/13 did not recognize any protein bands on Western blots performed under reducing conditions. However Western blotting analysis with PM6/13 under non-reducing conditions revealed strong detection of the parent GP IIIa molecule, of trypsin treated samples revealed recognition of an 80 kDa fragment at 1 min, faint recognition of a 60 kDa fragment at 60 min and no recognition of any product at 18 h treatment. Under similar conditions, SZ-21 recognized fragments at 80, 75 and 55 kDa with the 55kDa species persisting even after 18 h trypsin treatment. These studies confirm the epitopes recognised by PM6/13 and SZ-21 to be distinct and that PM6/13 represents a useful tool to differentiate the characteristics of fibrinogen and fibronectin binding to the GPIIb-IIIa complex on activated platelets.

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