Ecological and Physiological Studies on Marine Methane-Oxidizing Bacteria.

甲烷被称为“甲烷营养菌”的有限微生物群在生物学上利用。这些群体是由一些有限种类的酵母和细菌组成的。在淡水地区和发酵方面对甲烷氧化菌进行了大量的研究。尽管甲烷气体不仅分布在富营养化的海岸沉积物中，而且最近也发现了热喷口和冷渗区，但对海洋甲烷氧化细菌的研究还不多。在不添加有机物的基础培养基中，以甲烷+空气（1:1）为气相，尝试培养海洋甲烷化养菌群。海岸沉积物在培养基中孵育一个月后，将一部分转移到新鲜培养基中。重复培养3 ~ 4次。研究了培养基中微生物利用甲烷的能力，使用静息细胞与基础培养基、甲烷和空气。随着时间的推移，证实了这些细胞利用甲烷和氧气并产生二氧化碳。利用该方法对大池湾、Aburatsubo湾、东京湾等沿海地区和相模湾冷渗区等近海地区的甲烷氧化菌分布情况进行了研究。由于难以在琼脂平板上形成菌落，目前用纯培养方法分离这些细菌是不成功的。电镜观察这些微生物的薄片，发现存在甲烷氧化菌特征的II型膜结构。对沿海地区沉积物芯水和水柱中甲烷的分布进行了研究。

Methane is utilized biologically by limited groups of microorganisms called "methanotroph". These groups are composed of some limited spe-cies of yeasts and bacteria. There has been rather a lot of works on methanotrophs in freshwater areas and fermentasion aspects. There has been not so many works on marine methane oxidizing bacteria in spite of the methane gas distribution not only in the eutrophicated coastal sediments but also recently found areas of hot thermal venting and cold seep. We tried to culture marine groups of methanotroph using basal medium of noaddition of organic matter, and addition of methane + air (1:1) as air phase. After incubation of coastal sediment in the medium for one month, a portion was transferred to fresh medium. Such culture was repeated 3 to 4 times. Microorganisms in the medium was studied for the ability to utilize methane using resting cells with basal medium, methane and air. It was confirmed that these cells utilized mthane and oxygen and produced carbon dioxide with the progress of time. This method was used to check the distribution of methane oxidizing bacteria in coastal areas, such as Otsuchi bay, Aburatsubo Inlet and Tokyo Bay, and in off shore area like cold seep area of Sagami Bay. Isolation of these bacteria as pure culture was not successflu at present time because of the dificulty of colony formation on agar plates. Electron microscopicobservation with thin section of such microorganisms revealed the presence of II types of membrane structure which is charecteristics of methanotrophs. Distribution of methane in the core waters of sediments and in the water columns was also studied in the coastal areas.