Šrédlová Kamila, Šírová Kateřina, Stella Tatiana, Cajthaml Tomáš
Faculty of Science, Institute for Environmental Studies, Charles University, Benátská 2, 12801 Prague 2, Czech Republic.
Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 14220 Prague 4, Czech Republic.
Toxics. 2021 Apr 8;9(4):81. doi: 10.3390/toxics9040081.
Metabolites of polychlorinated biphenyls (PCBs)-hydroxylated PCBs (OH-PCBs), chlorobenzyl alcohols (CB-OHs), and chlorobenzaldehydes (CB-CHOs)-were incubated in vitro with the extracellular liquid of , which contains mainly laccase and low manganese-dependent peroxidase (MnP) activity. The enzymes were able to decrease the amount of most of the tested OH-PCBs by > 80% within 1 h; the removal of more recalcitrant OH-PCBs was greatly enhanced by the addition of the laccase mediator syringaldehyde. Conversely, glutathione substantially hindered the reaction, suggesting that it acted as a laccase inhibitor. Hydroxylated dibenzofuran and chlorobenzoic acid were identified as transformation products of OH-PCBs. The extracellular enzymes also oxidized the CB-OHs to the corresponding CB-CHOs on the order of hours to days; however, the mediated and nonmediated setups exhibited only slight differences, and the participating enzymes could not be determined. When CB-CHOs were used as the substrates, only partial transformation was observed. In an additional experiment, the extracellular liquid of , which contains predominantly MnP, was able to efficiently transform CB-CHOs with the aid of glutathione; mono- and di-chloroacetophenones were detected as transformation products. These results demonstrate that extracellular enzymes of ligninolytic fungi can act on a wide range of PCB metabolites, emphasizing their potential for bioremediation.
多氯联苯（PCBs）的代谢产物——羟基化多氯联苯（OH - PCBs）、氯苄醇（CB - OHs）和氯苯甲醛（CB - CHOs），在体外与[具体对象]的细胞外液一起孵育，该细胞外液主要含有漆酶和低锰依赖性过氧化物酶（MnP）活性。这些酶能够在1小时内将大多数测试的OH - PCBs的量减少80%以上；通过添加漆酶介体丁香醛，更难降解的OH - PCBs的去除率大大提高。相反，谷胱甘肽极大地阻碍了反应，表明它起到了漆酶抑制剂的作用。羟基化二苯并呋喃和氯苯甲酸被鉴定为OH - PCBs的转化产物。细胞外酶还能在数小时到数天的时间内将CB - OHs氧化为相应的CB - CHOs；然而，介导和非介导的实验设置仅表现出轻微差异，且无法确定参与的酶。当使用CB - CHOs作为底物时，仅观察到部分转化。在另一个实验中，主要含有MnP的[具体对象]的细胞外液能够在谷胱甘肽的帮助下有效地转化CB - CHOs；检测到单氯和二氯苯乙酮作为转化产物。这些结果表明，木质素分解真菌的细胞外酶可以作用于多种PCB代谢产物，强调了它们在生物修复方面的潜力。
