Introduction, Survival and Activity of Herbicide-Degrading Microorganisms, and Possible Effects of Inoculation on Native Microbial Ecosystems

• Unité de recherche: COST
• Numéro de projet: C98.0111
• Titre du projet anglais: Introduction, Survival and Activity of Herbicide-Degrading Microorganisms, and Possible Effects of Inoculation on Native Microbial Ecosystems

Mots-clé (Anglais)

Bioaugmentation; herbidice degradation; sphingomonas

Programme de recherche (Anglais)

COST-Action 830 - Microbial inoculants in agriculture and the environment

Description succincte (Anglais)

See abstract

Partenaires et organisations internationales (Anglais)

B, DK, FIN, F, D, GR, H, I, NL, N, PL, P, E, S, CH, GB

Résumé des résultats (Abstract) (Anglais)

Phenoxyacid herbicides like mecoprop, dichlorprop and 2,4-dichlorophenoxyacetic acid (2,4-D) are used in agriculture, private gardening, and roads and in construction for purposes of weed control. Since these chemicals are released into the environment on purpose, a significant fraction ends up as undegraded residues. This project focused on the possibilities to achieve targeted degradation of phenoxyacid herbicides in agricultural soils by applying specific microorganisms capable of completely metabolizing these compounds, and to study effects of introducing bacteria in the environment. Targeted degradation of mecoprop in natural non-sterile agricultural soil under laboratory conditions could be achieved by applying the bacterial strain Sphingomonas herbicidovorans MH. Application of the strain at 107 cells per gram soil resulted in two- to threefold faster rates of mecoprop degradation than spontaneously. Effects of introducing the bacterium on the natural bacterial community were investigated with the method of terminal restriction fragment length polymorphisms (T-RFLP). First, the level of natural fluctuations in the community structure was determined in a one-and-a-half year monitoring study of an agricultural soil by using the T-RFLP method. This showed that natural fluctuations seen with T-RFLP are very minor. Secondly, a field study was started to follow the community fluctuations in agricultural fields applied with herbicides, which showed more prominent changes after herbicide application. Currently running mesocosm studies will be used to address the capacity of S. herbicidovorans to degrade mecoprop under semi-field conditions and to monitor simultaneously community changes by T-RFLP induced by addition of the bacteria and/or the herbicides over a longer time period.

Références bases de données (Anglais)

Swiss Database: COST-DB of the State Secretariat for Education and Research Hallwylstrasse 4 CH-3003 Berne, Switzerland Tel. [phone] Swiss Project-Number: C98.0111