Oxidation of benzo[a]pyrene by laccase in soil enhances bound residue formation and reduces disturbance to soil bacterial community composition.
Oxidation of benzo[a]pyrene by laccase in soil enhances bound residue formation and reduces disturbance to soil bacterial community composition.
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DOI：
10.1016/j.envpol.2018.06.075
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发表时间：
2018-11
影响因子：
8.9
通讯作者：
Jun Zeng;Qinghe Zhu;Yucheng Wu;J. Shan;R. Ji;Xiangui Lin
中科院分区：
文献类型：
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作者：
Jun Zeng;Qinghe Zhu;Yucheng Wu;J. Shan;R. Ji;Xiangui Lin
漆酶能够快速氧化苯并[a]芘。认为苯并[a]芘的氧化导致的水溶性增加的代谢产物可能刺激随后的矿化。然而，到目前为止，还没有实验证据支持这一点。本文研究了漆酶对苯并[a]芘在土壤中的归趋及其对土壤细菌的影响。漆酶处理促进了苯并[a]芘从土壤中的消散（15.6%），并伴随着微量矿化（<0.58 ± 0.02%）和大量结合残留物的形成（约80%）。漆酶处理后，胡敏素结合残基的比例增加了约15%，这主要是由于胡敏素与残基的共价结合。在培养过程中，细菌16S rRNA和多环芳烃环羟化双加氧酶基因的丰度没有明显变化。与此相反，苯并[a]芘与漆酶处理导致在一个较小的移动的细菌群落组成，表明减少干扰土壤微生物群落。这些结果表明，漆酶对苯并[a]芘污染土壤的解毒作用主要是通过共价键结合的方式增强了苯并[a]芘与土壤有机质的结合残留。
Laccases are capable of rapidly oxidizing benzo[a]pyrene. It is thought that the metabolites with an increase in water solubility caused by the oxidation of benzo[a]pyrene may stimulate the subsequent mineralization. However, to date, there has been no experimental evidence to support this. In this study, the fate of benzo[a]pyrene in soil affected by laccase amendment and the resulting soil bacterial responses were investigated. Laccase amendment promoted benzo[a]pyrene dissipation (15.6%) from soil, accompanied by trace mineralization (<0.58 ± 0.02%) and substantial bound residue formation (∼80%). An increase of ∼15% in the bound residue fraction was observed by laccase amendment, which mainly resulted from covalent binding of the residues to humin fraction. During the incubation, the abundance of bacterial 16S rRNA and polycyclic aromatic hydrocarbon ring-hydroxylating dioxygenase genes did not change markedly. In contrast, benzo[a]pyrene treated with laccase resulted in a smaller shift in the bacterial community composition, indicating a reduced disturbance to the soil microbial communities. These results here suggest that benzo[a]pyrene contaminated soil can be detoxified by laccase amendment mainly due to the enhanced bound residue formation to soil organic matter via covalent binding.