engleski

Evolution of bacteria Lactobacillus plantarum strains from Croatian autochthonous fermented products during prolonged stationary phase

By growing bacterial strains in nutrient deprivation conditions we have shown that lactic acid bacteria are capable to live during long term growth and to enter in prolonged stationary phase. We also showed that evolution of bacterial strains, as well as mutation, is a random process. We have obtained the differences in metabolism between 1-day-old and 10-day-old strains. During long term growth, the mutations that affect genes encoding proteins involved in metabolism occurred. Long term growth also had an impact on differential expression of proteins involved in cell division, homologous recombination, translation and transcription. Proteins involved in cell division enable cells to adopt stress conditions and live during prolonged stationary phase. We concluded that long term growth do not have affect L. plantarum competition against S. enterica, although production of lactic acid, which decreases pH and has antibacterial effects, was reduced in the 10-day-old L. plantarum strain. The studies on the lactic acid bacteria growth and adaptation to stress conditions are of great interest due to the extensive use of these microorganisms in the food industry. Obtained 10-day old L. plantarum strains with different production of lactic can be used as new starter culture in food industry to get products with new nutritional, organoleptic, and shelf-life characteristics. 10-day-old L. plantarum strains can also help fermented food not to spoil and to be safe for human consummation based on its competition over food borne pathogens.

Lactobacillus plantarum; evolution; long term starvation

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