Induction and Transcriptional Regulation of Laccases in Fungi

Abstract

Fungal laccases are phenol oxidases widely studied for their use in several industrial applications, including pulp bleaching in paper industry, dye decolourisation, detoxification of environmental pollutants and revalorization of wastes and wastewaters. The main difficulty in using these enzymes at industrial scale ensues from their production costs. Elucidation of the components and the mechanisms involved in regulation of laccase gene expression is crucial for increasing the productivity of native laccases in fungi. Laccase gene transcription is regulated by metal ions, various aromatic compounds related to lignin or lignin derivatives, nitrogen and carbon sources. In this manuscript, most of the published results on fungal laccase induction, as well as analyses of both the sequences and putative functions of laccase gene promoters are reviewed. Analyses of promoter sequences allow defining a correlation between the observed regulatory effects on laccase gene transcription and the presence of specific responsive elements, and postulating, in some cases, a mechanism for their functioning. Only few reports have investigated the molecular mechanisms underlying laccase regulation by different stimuli. The reported analyses suggest the existence of a complex picture of laccase regulation phenomena acting through a variety of cis acting elements. However, the general mechanisms for laccase transcriptional regulation are far from being unravelled yet.

Influence of Trace Elements on Ligninolytic Enzyme Activity of Pleurotus ostreatus and P. pulmonarius

“…Among those external factors, trace elements are recognized as agents that can interact with the enzymes or participate in gene regulation processes, mainly on a transcriptional level (Baldrian 2003;Piscitelli et al 2011). Generally, these elements in low concentrations are necessary for synthesis and function of the ligninolytic enzymes, while their higher amounts present potent inhibitors of enzymatic reactions (Vallee and Ulmer 1972).…”

Ultrasound-intensified laccase production from Trametes versicolor

“…The white-rot fungus, Trametes versicolor, is reported to be an excellent producer of laccase, and significant research has been conducted to evaluate T. versicolor laccase production [15][16][17]. However, no studies investigating the ultrasonic-stimulation of laccase in T. versicolor have been reported.…”

Fungal Bioremediation of Emerging Micropollutants in Municipal Wastewaters

“…Laccases are glycosylated multicopper oxidases whose production is barely constitutive in fungi; gene transcription is regulated by metal ions, various aromatic compounds related to lignin, nitrogen and carbon: all these factors act synergically, stimulating laccase production (Piscitelli et al 2011). Moreover, laccase stability in a wide range of chemical-physical condition makes them good candidates to be used as biocatalysts for industrial purposes (Riva 2006).…”