Optimization of 2,4-dichlorophenol biodegradation by Priestia megaterium SA3

Chlorophenols pose significant risks to both ecosystems and human health. They are released into the environment for a variety of reasons. 2,4-D, a chlorophenol, is a herbicide and is extensively used in agricultural areas. 2,4-DCP is one of the degradation products of 2,4-D and is highly harmful to health. Degradation of 2,4-DCP is crucial for eliminating the risks it poses. Degradation is possible using various approaches, but biodegradation is the most environmentally friendly approach considering the end product it produces. In this study, the biodegradation of 2,4-DCP by a local isolate, Priestia megaterium SA3, was studied. For this purpose, cultures containing certain amounts of 2,4-DCP were cultivated in minimal medium, and after incubations, 2,4-DCP degradation was confirmed by phenol determination analysis. Subsequently, the bacterial isolate's 2,4-DCP degradation was optimized in culture. Degradation was confirmed by HPLC analysis. Transcriptome analysis revealed changes in gene regulation in Priestia megaterium SA3 during 2,4-DCP degradation in culture. Furthermore, the toxicity of the final degradation products formed during culture incubation was demonstrated by phytotoxicity and cytotoxicity tests. The study revealed that Priestia megaterium SA3 can biodegrade 2,4-DCP at concentrations around 50-100 ppm, and the toxicity of the final products is much lower than that of 2,4-DCP. Considering this, the study results demonstrate an environmentally friendly approach.