Transcriptional response of lignin-degrading enzymes to 17α-ethinyloestradiol in two white rots

Abstract

Fungal, ligninolytic enzymes have attracted a great attention for their bioremediation capabilities. A deficient knowledge of regulation of enzyme production, however, hinders the use of ligninolytic fungi in bioremediation applications. In this work, a transcriptional analyses of laccase and manganese peroxidase (MnP) production by two white rots was combined with determination of pI of the enzymes and the evaluation of 17α-ethinyloestradiol (EE2) degradation to study regulation mechanisms used by fungi during EE2 degradation. In the cultures of Trametes versicolor the addition of EE2 caused an increase in laccase activity with a maximum of 34.2±6.7U g-1 of dry mycelia that was observed after 2 days of cultivation. It corresponded to a 4.9 times higher transcription levels of a laccase-encoding gene (lacB) that were detected in the cultures at the same time. Simultaneously, pI values of the fungal laccases were altered in response to the EE2 treatment. Like T.versicolor, Irpex lacteus was also able to remove 10mg l-1 EE2 within 3 days of cultivation. While an increase to I. lacteusMnP activity and MnP gene transcription levels was observed at the later phase of the cultivation. It suggests another metabolic role of MnP but EE2 degradation. A deficient knowledge of regulation of enzyme production hinders the use of ligninolytic fungi in bioremediation applications. In the cultures of Trametes versicolor the addition of 17α- ethinylestradiol (EE2) caused an increase in laccase activity with a maximum of 34.2 ± 6.7 Ug-1 of dry mycelia that corresponded to a 4.9 times higher transcription levels of a laccase encoding gene lacB. Simultaneously, pI values of the fungal laccases were altered in response to the EE2 treatment. While an increase to MnP activity and MnP gene transcription levels was observed in Irpex lacteus first after the removal of EE2 from the cultures. It suggests another metabolic role of MnP but EE2 degradation. © 2012 The Authors. Published by Society for Applied Microbiology and Blackwell Publishing Ltd.