Growth and Phylogenetic Characteristics of a Pelagic Marine Bacterium, Alteromonas sp. KE10, Adapted to Low-nutrient Environments

抄録

Growth of the marine bacterial strain KE10, Vibrio harveyi, Cytophaga latercula, and Escherichia coli was examined in two different concentrations of organic nutrients; 0.2 and 200mg carbon per liter (C/1). All bacteria grew at these two concentrations with a relatively lower growth rate at 0.2mg C/1. The ratio of the growth rate at 0.2mg C/1 to 200mg C/1 ranged from 0.70 to 0.44 for KE10 and 0.34 to 0.16 for the other bacterial strains tested. At the lower concentration, 0.2mg C/1, KE10 showed the highest growth rate among the strains examined. At the stationary growth phase, KE10 reached 2.8×10⁶cells/ml, which was ten times higher than the maximum cell densities of other bacterial species. KE10 was a gram-negative, aerobic, rod-shaped bacterium and was motile by flagella. A phylogenetic analysis based on 16S rRNA gene and phenotypic characteristics showed that KE10 belonged to the genus Alteromonas and was closely related to Alteromonas infernus.