a Institute for Environmental Research , RWTH Aachen University , Aachen , Germany.
J Environ Sci Health B. 2014;49(2):69-78. doi: 10.1080/03601234.2014.844600.
Extracellular, oxidative soil enzymes like monophenol oxidases and peroxidases play an important role in transformation of xenobiotics and the formation of organic matter in soil. Additionally, these enzymes may be involved in the formation of non-extractable residues (NERs) of xenobiotics during humification processes. To examine this correlation, the fate of the fungicide (14)C metalaxyl in soil samples from Ultuna (Sweden) was studied. Using different soil sterilization techniques, it was possible to differentiate between free, immobilized, and abiotic ("pseudoenzyme"-like) oxidative activities. A correlation between the formation of metalaxyl NER and soil organic matter content, biotic activities, as well as extracellular phenoloxidase and peroxidase activities in the bulk soil and its particle size fractions was determined. Extracellular soil-bound enzymes were involved in NER formation (up to 8% of applied radioactivity after 92 days) of the fungicide independently from the presence of living microbes and different distributions of the NER in the soil humic subfractions.
细胞外氧化土壤酶，如单酚氧化酶和过氧化物酶，在土壤中转化外来化合物和形成有机质方面发挥着重要作用。此外，这些酶可能参与了腐殖化过程中外来化合物的不可提取残留物（NER）的形成。为了研究这种相关性，研究了来自瑞典乌特努（Ultuna）的土壤样本中杀菌剂（14）C 金属axyl 的命运。使用不同的土壤灭菌技术，可以区分自由、固定和非生物（类似“伪酶”）氧化活性。确定了金属axyl NER 的形成与土壤有机质含量、生物活性以及土壤中多酚氧化酶和过氧化物酶活性及其颗粒大小分数之间的相关性。细胞外土壤结合酶参与了杀菌剂 NER 的形成（92 天后达到施用量的 8%），而与微生物的存在与否以及 NER 在土壤腐殖质亚组分中的不同分布无关。
