As a feasible alternative for biological degradation of halogenated organic compounds that are not utilized by organisms as carbon sources, a cometabolic oxidative conversion by methane-utilizing organisms, which produces nonspecific monooxygenases, has been suggested. Three unidentified methylotrophic strains, Me046, Me082, and Me096 and three identified methylotrophic strains, Methylocystis parvus (KCTC 1618) Methylosinus trichosporium(KCTC1619) and Methylomonas methy lovora(KCTC 1688) were investigated for their capacities of growing on methane or methanol and of transforming TCE at different conditions. Me082 and Me096 were appeared to grow rapidly on methane and transform TCE with high initial transformation rates and high transformation capacities. Resting cells of Me096 degraded TCE more raidly than cells with cosubstrates such as methane or methanol. Formate amendment increased transformation capacity of Me096 while copper contnet in medium inactivated cells. Me096 was enriched in a batch culture and continuously methane-fed culture and inoculated in twotage dispersed growth reactor to remove 10mg/1 of TCE contained in medium. The performance and characteristics of two-stage dispersed-growth reactor was analyzed by growing-biofilm model. Operation results for 25 hours were compared with the model prediction to verify the validity of model and were used to predict the long-term operation results.