We investigated the use of POXA1b laccase from Pleurotus ostreatus for the oxidation of anthracene into anthraquinone. We show that different pathways can occur depending on the nature of the redox mediator combined to laccase, leading to different structural isomers. The laccase combined with 2,2′-azine-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) leads to the formation of 1,4-anthraquinone and/or 1,2-anthraquinone. The unprecedented role of carbon nanotubes (CNTs) as redox mediators for oxidation of anthracene into 9,10-anthraquinone is shown and corroborated by density-functional theory (DFT) calculations. Owing to the efficient adsorption of anthraquinones at CNT electrodes, anthracene can be detected with low limit-of-detection using either laccase in solution, CNT-supported laccase or laccase immobilized at magnetic beads exploiting the adhesive property of a chimeric hydrophobin-laccase.

Fungi produce surface-active proteins, among which hydrophobins are the most characterized and attractive also for their ability to form functional amyloids. Our most recent findings show that these abilities are shared with other classes of fungal proteins. Indeed, in this paper, we compared the characteristics of a class I hydrophobin (Vmh2 from Pleurotus ostreatus) and an unknown protein (named PAC3), extracted from the marine fungal strain Acremonium sclerotigenum, which does not belong to the same protein family based on its sequence features. They both proved to be good biosurfactants, stabilizing emulsions in several conditions (concentration, pH, and salinity) and decreasing surface tension to a comparable value to that of some synthetic surfactants. After that, we observed for both Vmh2 and PAC3 the formation of giant fibers without the need for harsh conditions or long incubation time, a remarkable ability herein reported for the first time.

A chimeric enzyme based on the genetic fusion of a laccase with a hydrophobin domain was employed to functionalize few-layer graphene, previously exfoliated from graphite in the presence of the hydrophobin. The as-produced, biofunctionalized few-layer graphene was characterized by electrochemistry and Raman spectroscopy, and finally employed in the biosensing of phenols such as catechol and dopamine. This strategy paves the way for the functionalization of nanomaterials by hydrophobin domains of chimeric enzymes and their use in a variety of electrochemical applications.