Carbon-nanotube-supported POXA1b laccase and its hydrophobin chimera for oxygen reduction and picomolar phenol biosensing

The laccase mediator system at carbon nanotubes for anthracene oxidation and femtomolar electrochemical biosensing

“…We have recently shown its facile adsorption on MWCNT electrodes for sensitive catechol and dopamine sensing. 20 Fig. 3 shows the detection of anthraquinone products at different concentrations of anthracene in the presence of POXA1b laccase in solution or adsorbed at MWCNT electrodes, with and without ABTS.…”

“…[16][17][18][19] We recently produced in Pichia pastoris a chimera by fusion of POXA1b with a hydrophobin, a self-assembling adhesive protein produced by the same fungus P. ostreatus, making laccase prone to be immobilized at different types of materials such polystyrene beads, graphene nanosheets or CNTs. 16,18,20 Laccase redox mediators, the most common being the diammonium salt of 2,2′-azine-bis(3-ethylbenzothiazoline-6sulfonic acid (ABTS), have been used for many years, acting as electron relays when laccase are immobilized at electrode surface 12,13 or acting as an enhancer/promoter of the ability of laccase to catalyze the oxidation of high potential nonphenolic substrate. 21 Several studies have shown that this so-called laccase-mediator system is able to oxidize several PAHs such as anthracene or benzo(a)pyrene into quinoid products.…”

Fabrication of D–A–D type conducting polymer, carbon nanotubes and silica nanoparticle-based laccase biosensor for catechol detection

“…13 C NMR (100 MHz, CDCl 3 ): d 157. [1,2,5]selenadiazole (540 mg, 1.23 mmol) was added and dissolved at room temperature. The solution was stirred for 36 hours after the addition of bromine (0.52 mL, 10.1 mmol).…”

“…2 Among the other enzymes that are used for the detection of phenolic compounds, laccase enzyme is the most preferred because of its ease of use and preclusion of co-factors. [4][5][6] In literature, different laccase-based electrochemical biosensors have been developed for catechol determination using different sensor architectures. 2,3,[7][8][9][10] Conducting polymers (CPs) have been recognized as excellent materials that offer a variety of advantages for designing electrochemical biosensors with proper functionalization.…”

Innovative surface bio-functionalization by fungal hydrophobins and their engineered variants

“…Once the immobilization conditions were optimized, biofunctionalized few-layer graphene was deposited on glass carbon electrodes to detect catechol at micromolar sensitivity. An improvement of this biosensor was later developed by immobilizing the same fusion protein on multi-walled carbon nanotubes reaching higher sensitivity ( Sorrentino et al, 2021 ). More recently, Vmh2–laccase fusion protein was also immobilized on magnetic beads and used to detect three PAHs, upon their oxidation into quinones in the presence of a redox mediator.…”