Laccases for removal of recalcitrant and emerging pollutants.

Bioremediation of wastewater can be enhanced by the use of lignolytic enzymes such as laccases. Laccases oxidize, polymerize or transform phenolic or anthropogenic compounds to less toxic derivatives. Laccase substrates are diverse, and include phenols, dyes, pesticides, endocrine disrupters and polycyclic aromatic hydrocarbons, some of which can be oxidized by extracellular fungal or bacterial laccase. Despite their enormous potential, the use of laccases for decontamination has so far usually been limited to the laboratory scale due to high enzyme production costs. The use of lignocellulosic waste material and/or wastewater as culture media for the growth of microorganisms producing laccase is gaining popularity, but is still low profile due to the ever-present challenges of this approach. The last two decades have seen the publication of numerous reviews on laccases; however, information on laccase properties and production parameters remains sketchy. Hence, a global overview of parameters affecting the biocatalysis of pollutants by laccases, particularly with regard to the economical production of these enzymes using synthetic media and waste materials, is timely.

The N-terminal half of the core protein of hepatitis C virus is sufficient for nucleocapsid formation.

The core (C) protein of hepatitis C virus (HCV) appears to be a multifunctional protein that is involved in many viral and cellular processes. Although its effects on host cells have been extensively discussed in the literature, little is known about its main function, the assembly and packaging of the viral genome. We have studied the in vitro assembly of several deleted versions of recombinant HCV C protein expressed in E. coli. We demonstrated that the 75 N-terminal residues of the C protein were sufficient to assemble and generate nucleocapsid-like particles (NLPs) in vitro. However, homogeneous particles of regular size and shape were observed only when NLPs were produced from at least the first 79 N-terminal amino acids of the C protein. This small protein unit fused to the endoplasmic reticulum-anchoring domain also generated NLPs in yeast cells. These data suggest that the N-terminal half of the C protein is important for formation of NLPs. Similarities between the HCV C protein and C proteins of other members of the Flaviviridae are discussed.