Cold adaptation of Lactobacillus paraplantarum C7 isolated from kimchi

The effect of preadaptation at low temperature on cryoprotection was studied for Lactobacillus paraplantarum C7, a bacteriocin producer isolated from kimchi. L paraplantarum C7 cells in their log growth phase were incubated at 15 degreesC, 10 degreesC, or 5 degreesC for 2, 4, and 6 h, respectively, before being frozen at -70 degreesC. After 24 h of freezing, viable cells were counted after brief thawing. The freezing-thawing cycles were repeated three more times. Cells preadapted at 10 degreesC or 5 degreesC before freezing survived better than control cells, but preadaptation at 15 degreesC did not confer cryoprotection. Chloramphenicol addition did not destroy the cryoprotection, indicating that protein synthesis was not required for the development of cryoprotection. SDS-PAGE showed induction of a 6.5-kDa protein, a major cold-shock protein, in preadapted cells.