Trametes hirsuta and a purified laccase from this organism were able to degrade triarylmethane, indigoid, azo, and anthraquinonic dyes. Initial decolorization velocities depended on the substituents on the phenolic rings of the dyes. Immobilization of the T. hirsuta laccase on alumina enhanced the thermal stabilities of the enzyme and its tolerance against some enzyme inhibitors, such as halides, copper chelators, and dyeing additives. The laccase lost 50% of its activity at 50 mM NaCl while the 50% inhibitory concentration (IC50) of the immobilized enzyme was 85 mM. Treatment of dyes with the immobilized laccase reduced their toxicities (based on the oxygen consumption rate of Pseudomonas putida) by up to 80% (anthraquinonic dyes). Textile effluents decolorized with T. hirsuta or the laccase were used for dyeing. Metabolites and/or enzyme protein strongly interacted with the dyeing process indicated by lower staining levels (K/S) values than obtained with a blank using water. However, when the effluents were decolorized with immobilized laccase, they could be used for dyeing and acceptable color differences (E*) below 1.1 were measured for most dyes.
- American Society for Microbiology
- Decolorization and detoxification of textile dyes with a laccase ...
Pentachlorophenol degradation by Pseudomonas fluorescens
Fluorescent Pseudomonads strains were considered as plant growth promoting bacteria. They exhibited antagonistic activities against phytopathogens and showed bio-fertilizing properties. The strain Pseudomonas fluorescens PsWw128, isolated from wastewater, can use the pentachlorophenol (PCP) as the sole source of carbon and energy. High-performance liquid chromatography (HPLC) and spectrophotometric methods were used to follow the PCP degradation and biomass PsWw128 formation. However, the removal efficiency of...
Inhibitory effect of thiourea on biological nitrification process and its eliminating method
Thiourea is a typical nitrification inhibitor that shows a strong inhibitory effect against the biological nitrification process. The 50% inhibitory concentration (IC50) of thiourea on nitrification was determined to be 0.088 mg g VSS−1, and nitrifiers recovered from the thiourea inhibition after it was completely degraded. The thiourea-degrading ability of the sludge system was improved to 3.06 mg gVSS−1 h−1 through cultivation of thiourea-degrading bacteria by stepwise increasing the influent thiourea concentrati...
Mortality from selected diseases that can be transmitted by water – United States, 2003–2009
Diseases spread by water are caused by fecal–oral, contact, inhalation, or other routes, resulting in illnesses affecting multiple body systems. We selected 13 pathogens or syndromes implicated in waterborne disease outbreaks or other well-documented waterborne transmission (acute otitis externa, Campylobacter, Cryptosporidium, Escherichia coli (E. coli), free-living ameba, Giardia, Hepatitis A virus, Legionella (Legionnaires' disease), nontuberculous mycobacteria (NTM), Pseudomonas-related pneumonia or septicemia,...
Identification of the bacterial population in manganese removal filters
The aim of this study was to identify bacteria present in ripened manganese removal filters for drinking water production. The bacterial population was identified with ‘next generation’ DNA sequencing, and specific bacteria were quantified with quantitative polymerase chain reaction (qPCR) and characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis. The ‘next generation’ DNA sequencing analysis showed a bacteria population shift from the iron oxidizing...
EPA Proposes Two Test Methods and Guidance for Evaluating Antimicrobial Pesticides
The U.S. Environmental Protection Agency (EPA) has recently announced the availability of two proposed test methods and associated testing guidance for evaluating antimicrobial pesticides against two biofilm bacteria, Pseudomonas aeruginosa and Staphylococcus aureus, for comments. EPA states that registrants of antimicrobial products with public health claims are “required to submit efficacy data to EPA in support of the product’s registration” under the Federal Insecticide, Fungicide, and...