Aims: The use of herbicide effectively controls weeds in agricultural practice. However, its release to the surrounding surface water bodies may lead to environmental issues. The aim of this study was to isolate the bacteria that were able to remove 2,2-dichloropropionic acid (2,2-DCP) from a paddy field located in Malang. Methodology and results: The 2,2-DCP degrading bacteria were isolated and their ability to grow on higher 2,2-DCP concentrations (50 and 80 mM) was tested. Bacterial degradation of 2,2-DCP was examined through measurement of released chloride ions. The potential isolates were identified according to their 16S rDNA sequences. Two potential isolates, BB9.2 and BC14.3 were observed for their growth on 20, 50, and 80 mM 2,2-DCP. Isolate BC14.3 had the shortest cell doubling time of approximately 4.1 h with 100% 2,2-DCP (20 mM) utilization, whereas BB9.2 was only able to degrade 80% of 2,2-DCP at the same concentration. The 16S rDNA gene sequences suggested that BB9.2 and BC14.3 belong to Acinetobacter calcoaceticus and Pseudomonas plecoglossicida, respectively. Conclusion, significance and impact of study Bacterial strains with 2,2-DCP degrading potentials were successfully isolated from long-term exposed agricultural soil. They demonstrated notable utilization of the organic halide. This is the first time that strains of A. calcoaceticus and P. plecoglossicida were reported to utilize 2,2-DCP.

Halogenated compounds create the most important class of xenobiotic which commonly lead to pollution. Some of these compounds are very toxic and cause enormous problems to human health and to the environment. Many of these toxic chemicals have been shown to occur in various extreme habitats. Pollutant-degrading microorganisms, adapted to grow in various environments, play an important role in the biological treatment of polluted extreme habitats. The presence of dehalogenase producing microorganisms in extreme habitat in particular is necessary since the enzyme can catalyze the removal of a halogen atom from a substrate. Therefore, it can reduce the toxicity of the halogenated compound and some are of interest for study in industrial application. Thermophiles, psychrophiles, acidophiles, alkaliphiles and halophiles are types of extremophiles. Knowledge of the biodegradation of toxic chemicals in extreme environment is limited. Here, examples of dehalogenase producing bacteria isolated from various extreme conditions and its special characteristics/features will be discussed in this review.