Monitoring of Pseudomonas pseudoalcaligenes KF707 Labeled with gfp As a Reporter Gene

초록

Polychlorinated biphenyls (PCBs) are toxic pollutants and their degradation is quite slow in the environment. Recently, interests in bioremediation using PCB-degrading bacteria have increased. Terpenes are natural substrates with structural similarities to PCB. They also have been known to be widely present in the environment and relatively non-toxic to human. In a previous report, plant terpenes [p-cymene, (S)-(-)-limonene, α-pinene, and α-terpinene] have been found to be utilized by a PCB degrader and to induce bph (biphenyl dioxygenase) gene in pure culture. Therefore, it has been proposed that using terpenes rather than PCB congeners is very useful to stimulate PCB degradation. In this study, Pseudomonas pseudoalcaligenes KF707, a PCB-degrading gram-negative soil bacterium was used to determine whether the terpenoid stimulation of PCB degrader occurs in natural environment. First, P. pseudoalcaligenes KF707 was genetically tagged using transposon with gfp (green fluorescent protein) as a reporter gene. The population dynamics of gfp-labeled P. pseudoalcaligenes KF707 in PCB contaminated environment was examined with or without terpenoids added in microcosm. We found about 10-100 folds increase in population of PCB degraders with added terpenoids compared with control (non-terpenoids samples and biphenyl added samples). We proposed that gfp-monitoring system is very useful and terpenoids enhance the survivability of PCB degraders in PCB contaminated environment.