Isolation of new toluene-tolerant marine strains of bacteria and characterization of their solvent-tolerance properties

Abstract

To isolate and characterize new marine bacteria capable of tolerating high concentrations of organic solvents, and to understand the toxic effects of these chemicals on marine bacteria. Five marine bacteria able to tolerate 0.1% (v/v) toluene were isolated and characterized on the basis of their growth and survival rates in the presence of different organic solvents. The toluene-tolerant marine bacteria identified in this study could not grow in the presence of 0.1% (v/v) of several organic solvents with a log P(ow) higher than that of the toluene (which in theory should be less toxic than toluene). The mechanisms underlying solvent tolerance were explored. Isolates of four different genera were identified as toluene-tolerant. Toxicity of a second phase of an organic solvent toward these isolates could not be predicted on the basis of the solvents' log P(ow). To improve the biodegradation rate of some water-insoluble compounds, double-phase bioreactors can be used. This type of bioreactor will require strains able to grow in a salt-containing environment and able to tolerate a second phase of an organic solvent.