20 research outputs found
Antimicrobial lubricant formulations containing poly(hydroxybenzene)-trimethoprim conjugates synthesized by tyrosinase
Poly(hydroxybenzene)-trimethoprim conjugates were prepared using methylparaben as substrate of the oxida- tive enzyme tyrosinase. MALDI-TOF MS analysis showed that the enzymatic oxidation of methylparaben alone leads to the poly(hydroxybenzene) formation. In the presence of tri- methoprim, the methylparaben tyrosinase oxidation leads poly(hydroxybenzene)-trimethoprim conjugates. All of these compounds were incorporated into lubricant hydroxyethyl cellulose/glycerol mixtures. Poly(hydroxybenzene)-trimetho- prim conjugates were the most effective phenolic structures against the bacterial growth reducing by 96 and 97 % of Escherichia coli and Staphylococcus epidermidis suspen- sions, respectively (after 24 h). A novel enzymatic strategy to produce antimicrobial poly(hydroxybenzene)-antibiotic conjugates is proposed here for a wide range of applications on the biomedical field.The authors Idalina Gonçalves and Cláudia
Botelho would like to acknowledge the NOVO project (FP7-HEALTH-
2011.2.3.1- 5) for funding. Loïc Hilliou acknowledges the financial support
by FCT – Foundation for Science and Technology, Portugal
(501100001871), through Grant PEst-C/CTM/LA0025/2013 - Strategic
Project - LA 25 - 2013–2014, and by Programa Operacional Regional
do Norte (ON.2) through the project BMatepro – Optimizing Materials
and Processes^, with reference NORTE-07-0124-FEDER-000037
FEDER COMPETE
Efficiency of xenoestrogen 4-tert-octylphenol degradation by photochemical method
W pracy przestawiono wyniki badań nad fotodegradacją 4-tert-oktylofenolu (OP). Celem przeprowadzonych eksperymentów było porównanie efektywności metod unieszkodliwiania tego związku w homogenicznym roztworze wodnym. Degradację OP zbadano przy użyciu następujących metod: fotolizy bezpośredniej przy wykorzystaniu trzech różnych źródeł światła, fotosenybilizowanego utleniania oraz układu H2O2/UV.Results of the study on photodegradation of 4-tert-octylphenol (OP) are presented with the aim to compare its removal efficiency from aqueous solution. Various methods of OP degradation were tested: direct photolysis with the use of three different radiation sources, H2O2 UV advanced oxidation process and photosensitized oxidation
Removal of Emerging Contaminants by Fenton and UV-Driven Advanced Oxidation Processes
This paper is closed access.The removal efficiencies of four different
parabens (methylparaben (MP), ethylparaben (EP),
propylparaben (PP), and butylparaben (BP)) using
Fenton reagent, UV irradiation, UV/H2O2, and UV/
H2O2/Fe2+ were evaluated to assess the level of
paraben degradation achieved using different advanced
oxidation processes (AOPs). UV irradiation
by itself provided paraben conversions between 27
and 38 % after a reaction time of 180 min. The UV/
H2O2 system increased the paraben conversion to
values between 62 and 92 %, and the Fenton process
was revealed as inefficient in paraben degradation
within the experimental conditions used. Photo-
Fenton presented similar removal rates to the UV/
H2O2 process. Among the four parabens studied,
butylparaben was the most easily removed, and it
was possible to attain degradations higher than
90 %. In the UV/H2O2 and photo-Fenton processes,
the overall kinetic constant could be split into two
main components: direct oxidation by UV radiation
(photolysis) and oxidation by free radicals (mainly
HO•) generated from the photodecomposition of
H2O2. This work reveals that UV-driven oxidation
processes can be widely used to remove parabens
from contaminated aqueous solution