Study of the role of indigenous actinobacteria from activated sludge in the degradation of the fungicide fenhexamid

Fenhexamid is a fungicide from hydroxyanil family with excellent activity against phyto-pathogenic fungi such as Botrytis cinerea, Monilinia spp and Scleorotinia sclerottioum. The rate of disappearance of this fungicide in natural water seems to be slow and can be accumulated in the body of aquatic organisms. Therefore, it can be an endocrine disruptor for people who consume these contaminated organisms. Because of its toxicity to non-target species, finding microorganisms with ability to degrade this fungicide is of great interest in the bioremediation of polluted sites. Actinobacteria are microorganisms with an impressive enzymatic potential and are therefore able to live and adapt to the most polluted ecosystems. In the present study, seven strains of Actinobacteria were isolated from the activated sludge of the Ibn Ziad wastewater treatment plant (City of Constantine). The screening of these strains for the degradation of fenhexamid was evaluated by growth on a minimum solid mineral medium supplemented with fenhexamid at 50 ppm, 200 ppm and 500 ppm as sole carbon source. According to the results of phenotypic and molecular analysis, the Actinobacteria isolates were assigned to three different genera: Streptomyces, Actinomadura and Micrococcus. This study showed that the Actinobacteria recovered from activated sludge of a wastewater treatment plant on Algeria, could be used in the bioremediation of aquatic environments contaminated by this type of pesticides.