The objective of this work was to improve bioluminescence stability of Photobacterium phosphoreum when it stored in view of developing continuous on-line monitoring system for pullutants. Long-term experiments were made to determine the effect of immobilization and storage temperature on the maintenance and stability of bioluminescence from luminescent bacteria. The immobilized cells of P. phosphoreum were compared with free cells in terms of maintenance of bioluminescence at room temperature. The bioluminescence of cells immobilized showed higher bioluminescence intensity that free and strontium bioluminescence stability was investigated with free and immobilized cells stored at $20^{circ}C,; 4^{circ}C,; -20^{circ}C;and;-70^{circ}C$for 20 days. Both free and immobilized cells stored at $4^{circ}C$ emitted a stable bioluminescence while the bioluminescence markedly decreased with those stored at $20^{circ}C,;-20^{circ}C;and; -70^{circ}C$.