A new endosulfan-degrading fungus, Mortierella species, isolated from a soil contaminated with organochlorine pesticides

Abstract

Two new aerobic endosulfan-degrading fungal strains, Mortierella sp. strains W8 and Cm1-45, were isolated from soil contaminated with organochlorine pesticides. This is the first report on the biodegradation of endosulfan by Zygomycota. The strains isolated in this work degraded more than 70% and 50% of α and β-endosulfan, respectively, over 28 days at 25°C, whereas 8.2 μM of each a and β-endosulfan was added as the initial concentration in liquid cultures. Only a small amount of endosulfan sulfate, a persistent metabolite, was detected in both cultures, while these strains could not degrade endosulfan sulfate when incubated with endosulfan sulfate as the initial substrate. Both strains generate endosulfan diol as a first step in the degradation of endosulfan and then undergo further conversion to endosulfan lactone. The formation of these intermediates was confirmed by GC-MS. Mortierella spp. might be present as hyphae in contaminated soil because they were isolated using the soil washing method; therefore, these Mortierella spp. strains have potential for the bioremediation of contaminated sites with endosulfan.