Abstract
We previously reported on bacteria that are able to degrade an organophosphorus insecticide, fenitrothion (MEP), which is a thionoester compound with a nitro group. In this, study, bacteria that can degrade chlornitrofen (CNP), a diphenylether herbicide with a nitro group, and diazinon, a thionoester organophosphorus compound without a nitro group were investigated. Biodegradability of CNP was observed in Tempaku river water at all time points and diazinon-biodegradability was observed in a range from no degradation to nearly 80% by Handai method. Bacteria with CNP-degrading abilities of over 10% were 46 of 158 isolates from river water and 43 of 77 isolates from the cultured fluid of river water with CNP, and many of those isolates belonged to types of bacteria with MEP-degrading ability. Diazinon-degrading bacterum with abilities of over 10% was only one of 40 isolates from river water, but many diazinon-degradable bacteria were isolated from the cultured fluid of river water with diazinon for 2 weeks. One of isolates, it was identified as Pseudomonas alcaligenes, showed a high CNP-degrading ability and a low MEP-degrading ability, but did not degrade diazinon. An Acinetobacter lwoffii from the cultured fluid of river water with diazinon degraded both MEP and diazinon, but did not degrade CNP.
