Protection of bacteria against toxicity of phenol by immobilization in calcium alginate

Summary The antibacterial activity of phenol was determined by measuring inhibition of exponentially growing free and immobilized cells of Escherichia coli, Pseudomonas putida and Staphylococcus aureus. Immobilization of microorganisms in calcium alginate beads reduced the growth inhibition caused by bacteriostatic concentrations of phenol. The increase in phenol tolerance occurred at different culture conditions and growth rates of the cells. The strength of the effect, however, was found to correlate with the formation of colonies in the gel matrix. Dissolution of gel beads led to a substantial loss of the protection against phenol of immobilized-grown cells.