Chemostat production of plantaricin C by Lactobacillus plantarum LL441

Plantaricin C, a bacteriocin synthesized by Lactobacillus plantarum LL441, was optimally produced in chemostats kept at pH 5.0, 30°C, 150 rpm, and a dilution rate of 0.05 h21 when glucose was used as carbon source and a dilution rate of 0.10 to 0.12 h21 when sucrose or fructose was used instead. Production was abolished at high dilution rates, i.e., when the cells grew rapidly in all carbon sources. During a screening for bacteria with good technological properties, Lactobacillus plantarum LL441 was isolated from homemade cheese whey. It produces one bacteriocin, planta-ricin C (6), a 3.5-kDa peptide that is resistant to harsh envi-ronmental conditions and active at pH values from 2.0 to 7.0. It is bactericidal, and in some cases bacteriolytic, to a range of gram-positive organisms that include members of the genera Clostridium, Bacillus, and Staphylococcus and also to Listeria monocytogenes (6). Plantaricin C induces the formation of pores in the plasma membrane of sensitive cells, resulting in the dissipation of the proton motive force and in leakage o