Pseudomonas putida B2 is able to grow on o-nitrophenol (ONP) as the sole source of carbon and nitrogen. ONP was converted by a nitrophenol oxygenase to nitrite and catechol. Catechol was then attacked by a catechol 1,2-dioxygenase and further degraded through an ortho-cleavage pathway. ONP derivatives which were para-substituted with a methyl-, chloro-, carboxy-, formyl- or nitro-group failed t...

A new method, named "re-growth etching", which introduces a unique etchant "Au(I)", has been developed to fabricate large-sized porous gold nanostructures. The size of nanostructures and the number of pores can be regulated by the molar ratio of Ag and Au in the precursor. We have evaluated their performance by a model reaction of the reduction of 4-nitrophenol. The catalytic property of porous...

Inorganic polyphosphates, linear polymers of orthophosphate, occur naturally throughout biology and have many industrial applications. Their biodegradable nature makes them attractive for a multitude of uses, and it would be important to understand how polyphosphates are turned over enzymatically. Studies of inorganic polyphosphatases are, however, hampered by the lack of high-throughput method...

Using alkaline pH adjustment, the reaction between graphene oxide and L-ascorbic acid led to the formation of a carbocatalyst film with numerous graphene edges protruding out of basal planes, which had a markedly enhanced carbocatalytic activity for conversion of 4-nitrophenol to 4-aminophenol, as compared to that of the carbocatalyst counterpart without involving pH mediation.

CO(2)-switchable gold nanoparticles (AuNPs) were prepared by functionalizing AuNPs with CO(2)-switchable polymers. Their dispersion-re-dispersion in and separation from aqueous solution can be easily and reproducibly adjusted by CO(2) bubbling through and removal from the solution, enabling unique CO(2) controllable, efficient in situ recycling of NPs. As compared to non-functionalized AuNPs, t...

Highly ordered noncrystalline boron-doped nickel nanotube arrays are rapidly synthesized within 150 s by template-based electroless deposition. The as-prepared nanotubes have tunable magnetic properties and exhibit super efficient catalytic activity (∼70 s) for the reduction of 4-nitrophenol.

A new nanocluster of atomic precision, Au44(SC2H4Ph)32, is obtained by an oxidation-decomposition-recombination (ODR) process from Au25(SC2H4Ph)18 under mild conditions with high yield (75%). Among the investigated gold nanoclusters, Au44(SC2H4Ph)32 exhibits the highest catalytic activity for the reduction of 4-nitrophenol, especially at low temperature, indicating that the catalytic properties...

We have developed a spectrophotometric assay for the quantitative determination of feruloyl esterase activity based on release of 4-nitrophenol from a novel substrate, 4-nitrophenyl ferulate in an emulsion of Triton X-100 in aqueous buffer solution. The release of 4-nitrophenol was linear with reaction time at an early stage of the reaction with various esterase preparations. The method propose...

The design and synthesis of novel cyanopropyl polysilsesquioxane hollow spheres lead to production of a highly active and stable catalyst in the reduction of 4-nitrophenol catalyzed by Au nanoparticles.

This work reports a comparative electrochemical behaviour study and p-nitrophenol analytical detection using silver solid amalgam, hanging dropping mercury, and silver electrodes. For this, square wave voltammetry was employed, where the analytical responses and the redox mechanisms could be compared for reduction processes of 4-nitrophenol by analysis of the voltammetric responses. The analyti...