Effect of salts on luminescence of natural and recombinant luminescent bacterial biosensors

Effect of cations K(+), Na(+), Mg(2+), and Ca(2+) and anions Cl(-), SO(4)(2-), HCO(3)(-) , and CO(3)(2-) on the luminescence intensity of the marine luminescent bacterium Photobacterium phorphoreum (Microbiosensor B-17 677f) and the recombinant strain Escherichia coli with cloned lux operon of P. leiognathi (Ecolum-9). It is found that small concentrations of chlorides and sulfates of the cations studied had a concentration-dependent stimulatory effect on bacterial bioluminescence; as the concentration of agents increased, activation was succeeded by quenching. The strength of the inhibitory effect, which is characterized by EC(50), decreased in the series Ca(2+) > Na(+) > Mg(2+) > K(+). Carbonates and hydrocarbonates had a pronounced inhibitory effect on the bioluminescence intensity, determined by an increase in pH. We showed that some types of highly mineralized water with a high hydrocarbonate content have a marked inhibitory effect on the luminescence intensity of microbial luminescent biosensors, mimicking the effect of chemical pollutants.