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Research article - Peer-reviewed, 2009

Degradation of glyphosate and other pesticides by ligninolytic enzymes

Pizzul, Leticia; Castillo, Maria del Pilar; Stenström, John

Abstract

The ability of pure manganese peroxidase (MnP), laccase, lignin peroxidase (LiP) and horseradish peroxidase (HRP) to degrade the widely used herbicide glyphosate and other pesticides was studied in separate in vitro assays with addition of different mediators. Complete degradation of glyphosate was obtained with MnP, MnSO(4) and Tween 80, with or without H(2)O(2). In the presence of MnSO(4), with or without H(2)O(2), MnP also transformed the herbicide, but to a lower rate. Laccase degraded glyphosate in the presence of (a) 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), (b) MnSO(4) and Tween 80 and (c) ABTS, MnSO(4) and Tween 80. The metabolite AMPA was detected in all cases where degradation of glyphosate occurred and was not degraded. The LiP was tested alone or with MnSO(4), Tween 80, veratryl alcohol or H(2)O(2) and in the HRP assay the enzyme was added alone or with H(2)O(2) in the reaction mixture. However, these enzymes did not degrade glyphosate. Further experiments using MnP together with MnSO(4) and Tween 80 showed that the enzyme was also able to degrade glyphosate in its commercial formulation Roundup(A (R)) Bio. The same enzyme mixture was tested for degradation of 22 other pesticides and degradation products present in a mixture and all the compounds were transformed, with degradation percentages ranging between 20 and 100%. Our results highlight the potential of ligninolytic enzymes to degrade pesticides. Moreover, they suggest that the formation of AMPA, the main metabolite of glyphosate degradation found in soils, can be a result of the activity of lignin-degrading enzymes.

Keywords

Glyphosate; Manganese peroxidase; Laccase; Ligninolytic enzymes; Herbicide; Pesticides

Published in

Biodegradation
2009, Volume: 20, number: 6, pages: 751-759
Publisher: SPRINGER