Abstract

Ethidium bromide (EtBr) is a powerful carcinogen. Most molecular biology laboratories use EtBr in the research for nucleic acid visualization. However, EtBr waste seems to be efficiently degraded by only chemical method to date. In this study, Bacillus thuringiensisisolated from soil sample uncontaminated with EtBr was investigated for its ability in EtBr degradation. B. thuringiensis, strain PSU9 demonstrated the ability to degrade EtBr shown by clear zone formation on EtBr-supplemented Tryptic soy agar and thin layer chromatography (TLC). In TLC experiment, the results suggested that the large portion of EtBr could be degraded within 18 h using bacterial culture as well as cell-free supernatant of B. thuringiensis PSU9. These results may suggest the promising solution using microorganism to solve the problem of EtBr waste in the laboratory for the decrease of pollutant in the environment.

Key words: Ethidium bromide, biodegradation, Bacillus thuringiensis