벼 재배지 시료로부터 분리한 Methylomonas sp. SM-4의 특성

Abstract

A methane-oxidizing bacterium was isolated from rice paddy field soil sample in Jeollanam-do province, Korea, and characterized. The isolate was gram-negative, pink-orange pigmented and short rod (1.1~1.2 × 1.6~1.9 ㎛). The strain utilized methane and methanol as sole carbon and energy sources. It had an ability to grow at pH range of 5~8 with an optimum pH 7 and an optimum growth temperature of 30℃. Furthermore, the isolate could use KNO3, ammonium amidosulfate, yeast extract, L-alanine, L-glutamine, L-glutamic acid and DL-asparagine as a nitrogen source. The strain had antibiotic resistance towards polymyxin B but was negative to streptomycin, kanamycin, ampicillin, chloramphenicol and rifampicin. It was catalase and urease negative but observed to be oxidase positive. The isolate required copper concentration for their growth up to concentration range of 2 ~ 25𝜇M with an optimum of 10𝜇M. Phylogenetic analysis based on 16S rDNA sequences indicated that the strain formed a tight phylogenetic lineage with Methylomonas DH-1 with a value of 99.3% gene sequence similarity. So, we named the isolate an Methylomonas sp. SM-4.