AME 51:97-103 (2008)  -  DOI:

Extracellular peroxidase activity in an experimentally divided lake (Große Fuchskuhle, northern Germany)

Ulrike Buck1,3,*, Hans-Dietrich Babenzien1, Elke Zwirnmann2

1Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Department of Limnology of Stratified Lakes, Alte Fischerhuette 2, 16775 Stechlin, Germany
2Central Chemical Laboratory, Mueggelseedamm 310, 12587 Berlin, Germany
3Present address: Max Planck Institute of Marine Microbiology, Department of Molecular Ecology, Celsiusstr. 1, 28359 Bremen, Germany

ABSTRACT: Extracellular peroxidases act on aromatic compounds such as humic substances resulting in the formation of unstable radicals. Most organisms that are known to produce extracellular peroxidases are terrestrial, e.g. the wood-rotting fungus Phanerochaete chrysosporium and the Actinobacterium Streptomyces viridosporus. Only few studies focus on the action of these enzymes in the aquatic environment. In this study, the activities of extracellular peroxidases in 2 distinct compartments of the experimentally divided Lake Große Fuchskuhle, Germany (an acidic humic rich compartment and an almost neutral eutrophic compartment) and in the catchment area were investigated. Additionally, the effects of pH on extracellular peroxidase activity and of the size fractions of water samples associated with extracellular peroxidase activity were determined. Enzyme activity and the characterisation of the enzymes were assayed by oxididation of 2,2’-azino-di-(3-ethyl-benzthiazoline-6-sulphonic acid) (ABTS). In the humic rich compartment, extracellular peroxidase activity was (except for 1 month) significantly higher than in the eutrophic compartment, with highest activities during fall and winter. In contrast, no peroxidase activity was detected in the catchment area. The pH optimum of extracellular peroxidases was pH 3, and highest activity was detected in the 10 kDa–0.2 µm molecular weight class. Thus we documented the occurrence of extracelluar peroxidases in Lake Große Fuchskuhle and suggest that these enzymes are involved in the degradation of aromatic compounds such as humic substances.

KEY WORDS: Extracellular peroxidase · Exoenzymes · ABTS · Humic substances · Catchment area

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Cite this article as: Buck U, Babenzien HD, Zwirnmann E (2008) Extracellular peroxidase activity in an experimentally divided lake (Große Fuchskuhle, northern Germany). Aquat Microb Ecol 51:97-103.

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