Stress response in Lactococcus lactis and Streptococcus thermophilus induced by carbon starvation

L. lactis subsp. lactis IL1403, L. lactis subsp, cremoris MG1363, S. thermo philus A054, and S. thermophilus J34-3' were tested for growth in different sugar concentrations and for survival during stationary phase. Survival wa s improved when transition into stationary phase was induced by exhaustion of available carbon source in the growth medium. Carbon starvation induced resistance against 20 % ethanol in all four bacterial strains tested.L. lac tis subsp. lactis IL1403 became resistant upon carbon starvation against 3. 5 M NaCl and against 52 degrees C. L. lactis subsp. cremoris MG1363 also de veloped resistance against NaCl but not against heat. The two S. thermophil us strains developed resistance against heat (58 degrees C), ethanol (20 %) , and low pH (4.0) upon carbon starvation. For S. thermophilus A054 the pro tein patterns, as analysed by one-dimensional SDS-gel electrophoresis, indi cated that protein turn-over as well as de novo synthesis may be induced up on carbon starvation. The consequences of the carbon starvation induced transition from exponenti al to stationary growth phase for the performance of starter bacteria for c heese ripening are discussed.