An extracellular thermostable humic acid peroxidase (HaP3) was isolated from a Streptomyces sp. strain AH4. MALDI-TOF MS analysis showed that the purified enzyme was a monomer with a molecular mass of 60,215.18Da. The 26N-terminal residues of HaP3 displayed high homology with Streptomyces peroxidases. Optimal peroxidase activity was obtained at pH 5 and 80°C. HaP3 was stable at pH and temperature ranges of 4-8 and 60-90°C for 72 and 4h, respectively. HaP3 catalyzed the oxidation of 2,4-dichlorophenol, commercial humic acid, guiacol, and 2,6-dichlorophenol (50mM); L-3,4-dihydroxyphenylalanine (40 mM); 4-chlorophenol, 2,4,5-trichlorophenol, and 2,4,6-trichlorophenol (30 mM) in the presence of hydrogen peroxide. Sodium azide and potassium cyanide inhibited HaP3, which indicated the presence of heme components. These properties make HaP3 a potential strong candidate for future application in the elimination of natural humic acids in drinking water.
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http://dx.doi.org/10.1016/j.biortech.2012.01.153 | DOI Listing |
Nat Commun
January 2025
Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA, 01003, USA.
The extensive application of graphene nanosheets (GNSs) has raised concerns over risks to sensitive species in the aquatic environment. The humic acid (HA) corona is traditionally considered to reduce GNSs toxicity. Here, we evaluate the effect of sorbed HA (GNSs-HA) on the toxicity of GNSs to Gram positive Bacillus tropicus.
View Article and Find Full Text PDFEnviron Pollut
December 2024
Department of Safety, Health and Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung, Taiwan. Electronic address:
This is the first study to investigate the possible release of microplastic-derived dissolved organic matter (MP-DOM) in water from three major types of bio-based MPs, namely, polylactic acid (PLA), polyhydroxyalkanoate (PHA) and PLA-PHA mixtures, under ultraviolet (UV) irradiation conditions. At an initial MP concentration of approximately 5 g per liter, the release of MP-DOM from the studied MPs ranged from 1.55-6.
View Article and Find Full Text PDFChem Soc Rev
January 2025
Department of Chemistry, Purdue University, West Lafayette, Indiana, 47906, USA.
The light-absorbing chemical components of atmospheric organic aerosols are commonly referred to as Brown Carbon (BrC), reflecting the characteristic yellowish to brown appearance of aerosol. BrC is a highly complex mixture of organic compounds with diverse compositions and variable optical properties of its individual chromophores. BrC significantly influences the radiative budget of the climate and contributes to adverse air pollution effects such as reduced visibility and the presence of inhalable pollutants and irritants.
View Article and Find Full Text PDFHumic substances, such as Fulvic acid (FA) and humic acid (HA), are widely used for the remediation of heavy metal-contaminated soils due to their ability to enhance metal mobility and facilitate plant uptake. In this study, we conducted a pot experiment with alfalfa to investigate the effects of FA and HA amendments on the mobility of molybdenum (Mo) in the soil, its uptake by alfalfa plants, and subsequent changes in the microbial community. The results demonstrated that both FA and HA influence Mo accumulation in the soil and plants.
View Article and Find Full Text PDFEnviron Technol
December 2024
Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, Rennes, France.
A natural water sampled after a sand filtration step and spiked with four organic micropollutants (metolachlor ESA, metolachlor NOA, desethylatrazine and metaldehyde) was treated by a loose nanofiltration membrane. The Steric, Electric, and Dielectric model (SEDE model) was then used to predict the separation performance of the membrane towards the various ions and micropollutants in the water matrix in order to study the transport mechanism of ions and micropollutants through the membrane. The SEDE model was found to satisfactorily predict the rejection sequences of inorganic anions and cations, as well as neutral (desethylatrazine and metaldehyde) and charged (metolachlor ESA and metolachlor NOA) micropollutants.
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