Enzyme production by immobilized Phanerochaete chrysosporium was evaluated in airlift bioreactor and agitated cultures. Free mycelium and immobilized mycelium on alginate beads were tested in the decolourization of 50 and 500 mg/L of Remazol Brilliant Blue R. Dye concentration did not inhibit the fungi development in all tests. In addition, high decolourization percentage of dye was found with free mycelium (99%) in agitated flasks and with immobilized mycelium in airlift (98%). However, decolourization period by immobilized mycelium (120 h) was greater than that by the free mycelium (14 h). Important manganese peroxidase, lignine peroxidase and laccase activities were identified in decolourization process. Manganese peroxidase appeared to be promoted by high dye concentrations during the treatment with immobilized mycelium, but this enzyme was not detected with free mycelium in airlift. Bioreactor prompted also laccase and lignine peroxidase actions in both tests; free mycelium registered a maximum laccase action of 31.569 × 10 3 U/L in 70 h, whereas immobilized mycelium registered 1.680 × 10 3 U/L in 170 h, while lignine peroxidase secretion by free P. chrysosporium was higher (1.300 × 10 3 U/L) than immobilized mycelium (1.250 × 10 3 U/L). Maximum laccase activity coincided with the maximum percentage of decolourization, however, high peroxidase activity was identified from the start of dye treatment.
Surface interactions with pollutants and photons are key factors that affect the applications of TiO in environmental remediation. In this study, the solubilizing agents dimethylsulfoxide and polyoxyethylene sorbitan monooleate, which act as photon competitors, had no effect on the photocatalytic activity of TiO-C-Ag film in phenanthrene (PHE) removal. Fiberglass with TiO-C-Ag coating removed 91.1 ± 5.2 and 99.7 ± 0.4% of PHE in treatments using UVA (365-465 nm) and UVC (254 nm) irradiation, respectively. The use of fiberglass as a support increased the superficial area, thus allowing PHE sorption. C and Ag, which are electrically active impurities in TiO, enhanced its photocatalytic activity and thus the attraction of the pollutant to its surface. The use of high-frequency UV light (UVC) decreased the amount of carbon species deposited on the TiOCAg film surface. X-ray photoelectron spectroscopy of the TiO-C-Ag film revealed extensive oxidation of the carbon deposited on the film under UVC light and loss of electrons from Ag clusters by conversion of Ag to Ag.
Abstract-The polycyclic aromatic hydrocarbons (PAHs) are classified as a public health hazard, and priority pollutants to be eliminated from water. The degradation of PAHs is abetted by its low water solubility, yet countered by its attached to organic matter complicating the PAHs' removal from wastewater. In this study, the use of two different types of mechanisms to overcome the drawbacks of the presence of dissolved organic matter was evaluated in PHE (phenanthrene) removal. The combination of crude enzymes entrapped in alginate gels with heterogeneous photocatalysis adds the catalytic activity of the enzymes to PHE treatment without requiring special conditions. The application of photocatalysis techniques for water recuperation is subject to photon incidence over the catalyst, which affects the efficiency of the process. The combined system removed 94.3 ± 2.0% of PHE in the presence of polyoxyethylene sorbitan monooleate and dimethyl sulfoxide. The alginate gels were able to maintain the catalytic activity of the enzymes, while the TiO 2 -C-Ag was activated under low-energy UV light (365-465 nm) with the Ag islands acting as electron donors. The latter was confirmed in the surface analysis by X-ray photoelectron spectroscopy, which presented an increase in carbonyl groups in both materials and a change from Ag 0 to Ag 3+ after 13 h of treatment. The combination of both treatments improved removal in a single TiO 2 -C-Ag treatment.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.