Physiological and emission characteristics of the luminescent bacterium <Emphasis Type="Italic">Photobacterium Phosphoreum</Emphasis> from the White Sea

Growth and emission characteristics of the luminescent bacterium Photobacterium phosphoreum strain KM MGU 331 originating from the White Sea and isolated from the intestine of a bottom-dwelling fish, the European sculpin, Myoxocephalus scorpius, were analyzed. The strain is characterized by a high rate of colony formation and high intensity of light emission on agarized medium at 4° C as well as by highly efficient (5 × 10⁵ quanta s⁻¹ cell⁻¹) and prolonged (over 100 h) light generation upon submerged cultivation at 20°C. The acidic shift of pH in the medium didn’t exceed 0.3 pH units. Effects of temperature, pH, and sodium chloride concentration on emission characteristics of intact photobacterium cells were studied. The optimal temperature for luminescence was found to be 15°C. The maximum luminescence activity was stable in a wide pH range from 7.0 to 9.0. Luminescence occurred within the range of 0.2–3.8% NaCl with the maximum at 2.5%. The results obtained confirm the literature data suggesting that luminescent bacteria adapted to low-temperature conditions possess a highly conjugated system of electron transfer to luciferase.