Identification of various laccases induced by anthracene and contribution to its degradation in a Mediterranean coastal pine litter

Abstract

Mediterranean coastal ecosystems are known to be highly subject to natural and anthropic environmental stress. In this study, we examine the effects of anthracene as a common pollutant on the total microbial communities from a Pinus halepensis litter of a typical Mediterranean coastal site (Les Calanques, Marseille). The main objective was to identify the microbial factors leading the resilience of this ecosystem. Two questions were addressed: (i) how lignin-degrading enzymes (Laccase, Lignin-peroxidase and Mn-peroxidase) are affected by the presence of this molecule, (ii) whether the indigenous consortia are involved in its degradation in mesocosms under favorable incubation conditions (25 °C, 60% WHC) and after different time intervals (1 and 3 month(s)). We found a strong increase in laccase production in the presence of anthracene after 3 months, together with anthracene degradation (28%±5). Moreover 9,10-anthraquinone is detected as the product of anthracene oxidation after 3 months. However neither lignin-peroxidase activity nor Mn-peroxidase activity is detected. Laccase proteins directly extracted from litter were sequenced via Nano-LC-MS/MS and reveal twelve different peptide sequences induced by the presence of anthracene in the mesocoms. Our study confirms the major detoxification role of this enzymatic system and highlights the high degradation potential of fungal species inhabiting P. halepensis litter, a factor in the resilience of Mediterranean ecosystems.

Does anthracene affect microbial activities and organic matter decomposition? A comparative study in Pinus halepensis litters from Mediterranean coastal and inland areas

“…Enzyme extracts were further subjected to gel electrophoresis according to Qasemian et al (2011) in order to compare the phenoloxidase bands, as revealed by activity, under each treatment.…”

“…While the ways in which microorganisms mineralize organic contaminants have been extensively documented in studies on bioremediation technologies (Gianfreda and Rao, 2004;Novotný et al, 2004;D'Annibale et al, 2006;Wu et al, 2008), little is known about how far autochthonous microbial communities can withstand PAHs and whether they may be involved in degrading theses pollutants. In our previous study, we showed that anthracene, a model PAH, artificially added in laboratory experiments (Qasemian et al, 2011(Qasemian et al, , 2012 has no toxic effects on microbial activities expressed by whole microbial communities in Pinus halepensis litter from a coastal Mediterranean site. It therefore appeared useful to compare these results obtained from litters in coastal environments with the responses of microbial communities from inland areas.…”

Halotolerant laccases from Chaetomium sp., Xylogone sphaerospora, and Coprinopsis sp. isolated from a Mediterranean coastal area

“…In a previous study, we tested the effects of various metal and halide salts on the laccases from Marasmius quercophilus and we found that certain laccase isoforms were actually strongly inhibited by chloride ions (Farnet et al 2009). On the other hand, we found high laccase activities in a Pinus halepensis litter from Mediterranean coastal areas subjected to high osmotic pressure (Qasemian et al 2011). Furthermore, coastal areas are known to be highly urbanized and thus chronically subjected to anthropic pollutants such as PAHs.…”

Fate of carbamazepine and anthracene in soils watered with UV-LED treated wastewaters

“…They also play an important role in aromatic pollutant transformation. Previous studies have shown that fungal activities considerably enhanced anthracene transformation in soil microcosms (Steffen et al, 2007) and in litter microcosms (Qasemian et al, 2011). Moreover, recent studies on emerging pharmaceutical pollutants have reported that carbamazepine can also be transformed by laccases (Jelic et al, 2012;RodriguezeRodriguez et al, 2010;Zhang and Geißen, 2012).…”