Diclofenac is a non-steroidal anti-inflammatory drug for human, livestock and poultry. It has become a new pollutant of concern and can be frequently detected in the environment such as surface water, groundwater and sediments. So far, however, little is known about the environmental behavior of this new pollutant, especially its microbial degradation and transformation under anaerobic conditions.

Research scientist YAN Jun and associate researcher LI Xiuying of the Environmental Microbial Ecology Group at the Institute of Applied Ecology (IAE) of the Chinese Academy of Sciences (CAS) established an anaerobic microbial enrichment culture using river sediments polluted by Diclofenac. 

After an incubation of 160 days, the researchers found that in the anaerobic culture system, the microbial community was dominated by a Dehalogenimonas population, and this organohalogen-respiring bacterium accounted for approximately 56% of total microbial abundance. Their study showed that this Dehalogenimonas sp. was able to obtain energy for growth through dechlorinating Diclofenac to monochlorinated products and non-chlorinated aniline phenylacetic acid in the end. The quantitative real-time PCR analyses (Polymerase Chain Reaction) confirmed that the Dehalogenimonas sp. is a newly discovered strain capable of driving the dechlorination, so the researchers designated it as Dehalogenimonas sp. strain DCF.

The findings of this study expand the knowledge about the genus Dehalogenimonas, and provide new insights for understanding the environmental behavior, biodegradation and removal of the halogenated pollutants.

The study entitled "Organohalide Respiration with Diclofenac by Dehalogenimonas" has been published in Environmental Science & Technology. This study was funded by the National Natural Science Foundation of China, the National Key R&D Program of the Ministry of Science and Technology, and the Key Research Program of CAS for Frontier Sciences.