Characterization of Psychrotrophic Microorganism Isolated from Extraordinary Oxidative Condition
Isao YUMOTO*a, Hideaki IWATAa,b, Kosei KAWASAKIa, Nobutoshi ICHISEa,c, Naoki MORITAa, Hidetoshi MASTUYAMAb, and Hidetoshi OKUYAMAa,c
a Bioscience and Chemistry Division, Hokkaido National Industrial Research Institute, Tsukisamu Higashi, Toyohira-ku, Sapporo 062 Japan
b Departmet of Bioscience and Technology School of engineering Hokkaido Tokai University Minaminosawa, Minami-ku, Sapporo 005 Japan
c Laboratory of Environmental Molecular Biology, Graduate School of Earth Science, Hokkaido University, Sapporo 060, Japan
In the presence of oxygen, strictly aerobic and facultative anaerobic bacteria utilize oxygen as a terminal electron acceptor in acquiring energy. Aerobic organism produce lethal reactive oxygen species, including the superoxide anion, hydrogen peroxide and hydroxy radical as a result of oxygen metabolism. These reactive oxygen species oxidize fatty acids, initiating lipid peroxidation, oxidize protein, and damage DNA. The response of bacteria against oxidative stress has been extensively studied in enteric bacteria. However, little is known about the bacterium adapting oxidative environment. We initiated studies to understand how the bacteria adapt oxidative stress in the extraordinary oxidative environment. A psychrotrophic bacterium exhibiting high catalase activity constitutively was isolated from drain pool of fishery product processing plant. The drain pool is very oxidative condition causing large amount of hydrogen peroxide was used as a bleaching agent in the plant. A phylogenetic analysis based on 16S rRNA sequence showed that the isolate was very closely related to the genus Vibrio. According to the phylogenetic position and phenotypic characterization, although the isolate was not motile by means of flagella, it was assigned to the genus Vibrio. The strain was different from other reported Vibrio species in phylogenetic position and in some phenotypic characteristics.
