Identification and in Vitro Effectivenesstest of Four Isolates of Mercury-resistant Bacteriaas Bioaccumulation Agents of Mercury

Bioaccumulation of mercury is one of the reclamation methods in ex-gold mining areas. Mercury-resistant bacteria canbe used as a mercury bioaccumulation agent. The previous study in Mandor District West Kalimantan has collected four mercury-resistant bacteria from 62 samples with isolates code: HgTA1, HgTL2, HgRL and HgRA. The purpose of this study is to identify and verify the in vitro effectiveness ofthese four mercury-resistant bacteria. Identification of the bacteria is performed using16SrRNAsequencinganalysis, while the in vitro effectiveness test of the bacteriais done by using Canstein's selective media.The results show that the identification of bacterial isolates finds that HgTA1 and HgTL2 are Bacillus subtilis, HgRL is Burkholderia cepacia, and HgRA is Burkholderia cenosepacia. These three species of bacteria belong to the class of bacteria that are resistant to extreme conditions. Thus, these bacteria have anability toaccumulatemercury. Meanwhile, based on the test results of colony growth, detoxification abilities, mercury accumulation and bioaccumulation levels,three out of the four bacterial isolates are proven to be effective and superior to accumulate mercury i.e. HgRA, HgTA1 and HgTL2 isolates. Furthermore, these three isolates can be used as bioacculation agents of mercury-contaminated soil.