Atrazine is one of the most widespread chlorinated herbicides, leaving large bulks in soils and groundwater. The biodegradation of atrazine by bacteria is well described, but many aspects of the fungal metabolism of this compound remain unclear. Thus, we investigated the toxicity and degradation of atrazine by 13 rainforest basidiomycete strains. In liquid medium, Pluteus cubensis SXS320, Gloelophyllum striatum MCA7, and Agaricales MCA17 removed 30, 37, and 38%, respectively, of initial 25 mg L− 1 of the herbicide within 20 days. Deficiency of nitrogen drove atrazine degradation by Pluteus cubensis SXS320; this strain removed 30% of atrazine within 20 days in a culture medium with 2.5 mM of N, raising three metabolites; in a medium with 25 mM of N, only 21% of initial atrazine were removed after 40 days, and two metabolites appeared in culture extracts. This is the first report of such different outcomes linked to nitrogen availability during the biodegradation of atrazine by basidiomycetes. The herbicide also induced synthesis and secretion of extracellular laccases by Datronia caperata MCA5, Pycnoporus sanguineus MCA16, and Polyporus tenuiculus MCA11. Laccase levels produced by of P. tenuiculus MCA11 were 13.3-fold superior in the contaminated medium than in control; the possible role of this enzyme on atrazine biodegradation was evaluated, considering the strong induction and the removal of 13.9% of the herbicide in vivo. Although 88% of initial laccase activity remained after 6 h, no evidence of in vitro degradation was observed, even though ABTS was present as mediator. This study revealed a high potential for atrazine biodegradation among tropical basidiomycete strains. Further investigations, focusing on less explored ligninolytic enzymes and cell-bound mechanisms, could enlighten key aspects of the atrazine fungal metabolism and the role of the nitrogen in the process.

中文翻译：

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担子菌菌株对莠去津的生物降解和木质素分解酶的生产。


阿特拉津是最广泛使用的氯化除草剂之一，在土壤和地下水中残留大量。细菌对莠去津的生物降解已得到很好的描述，但该化合物的真菌代谢的许多方面仍不清楚。因此，我们研究了 13 种雨林担子菌菌株对莠去津的毒性和降解情况。在液体培养基中，Puteus Cubansis SXS320、Gloelophyllum striatum MCA7 和 Agaricales MCA17 在 20 天内分别去除了初始 25 mg L−1 除草剂的 30%、37% 和 38%。氮缺乏导致莠去津被Pluteus Cubansis SXS320降解；该菌株在含有 2.5 mM N 的培养基中 20 天内去除了 30% 的莠去津，并产生了三种代谢物；在含有 25 mM N 的培养基中，40 天后仅去除了 21% 的初始莠去津，并且培养物提取物中出现了两种代谢物。这是首次报道担子菌生物降解莠去津过程中与氮可用性相关的这种不同结果。该除草剂还诱导 Datronia caperata MCA5、Pycnoporus sanguineus MCA16 和 Polyporus tenuiculus MCA11 合成和分泌细胞外漆酶。 P. tenuiculus MCA11 产生的漆酶水平在受污染的培养基中比对照高 13.3 倍；考虑到体内强烈的诱导作用和去除13.9%的除草剂，评估了该酶对莠去津生物降解的可能作用。尽管 6 小时后仍保留 88% 的初始漆酶活性，但没有观察到体外降解的证据，即使 ABTS 作为介质存在。这项研究揭示了热带担子菌菌株中莠去津生物降解的巨大潜力。 进一步的研究，重点关注较少探索的木质素分解酶和细胞结合机制，可以启发莠去津真菌代谢的关键方面以及氮在该过程中的作用。