Exoproteomic Study and Transcriptional Responses of Laccase and Ligninolytic Peroxidase Genes of White-Rot Fungus Trametes hirsuta LE-BIN 072 Grown in the Presence of Monolignol-Related Phenolic Compounds

Abstract

Being an abundant renewable source of aromatic compounds, lignin is an important component of future bio-based economy. Currently, biotechnological processing of lignin through low molecular weight compounds is one of the conceptually promising ways for its valorization. To obtain lignin fragments suitable for further inclusion into microbial metabolism, it is proposed to use a ligninolytic system of white-rot fungi, which mainly comprises laccases and peroxidases. However, laccase and peroxidase genes are almost always represented by many non-allelic copies that form multigene families within the genome of white-rot fungi, and the contributions of exact family members to the overall process of lignin degradation has not yet been determined. In this article, the response of the Trametes hirsuta LE-BIN 072 ligninolytic system to the presence of various monolignol-related phenolic compounds (veratryl alcohol, p-coumaric acid, vanillic acid, and syringic acid) in culture media was monitored at the level of gene transcription and protein secretion. By showing which isozymes contribute to the overall functioning of the ligninolytic system of the T. hirsuta LE-BIN 072, the data obtained in this study will greatly contribute to the possible application of this fungus and its ligninolytic enzymes in lignin depolymerization processes.

Xenobiotic Removal by Trametes hirsuta LE-BIN 072 Activated Carbon-Based Mycelial Pellets: Remazol Brilliant Blue R Case Study

“…A possible explanation for the induction of T. hirsuta laccases by activated carbon is the presence of polycyclic aromatic hydrocarbons or other aromatic compounds formed during pyrolysis in its composition [59]. As it was previously shown, these compounds could be laccase inducers [23,[60][61][62][63][64]. Thus, at least in the case of T. hirsuta, the inclusion of activated carbon not only improves the adsorption properties of fungal pellets but also increases the production of laccase.…”

“…As a result, it was shown that for T. hirsuta, the presence of RBBR induced the transcription of lacA and lacB, while the transcription of the other laccase genes was either suppressed or unaffected. Previously, we have already shown that, as a universal "expressed by default" oxidative exoenzyme, LacA plays an important role in the detoxification of small aromatic compounds by T. hirsuta [21,23]. With respect to LacB, most probably its delayed induction was related to the accumulation of specific degradation products formed by the action of LacA.…”

“…Trametes hirsuta (Wulfen) Lloyd 1924 is a white-rot fungus belonging to the order Polyporales. Its ligninolytic system has been extensively studied for the degradation of lignin, xenobiotics, and monolignol-related compounds [20][21][22][23]. It was shown that, depending on the structure of the compound being degraded, T. hirsuta may prefer either laccases or peroxidases for its degradation.…”