Fragile cells of Lactobacillus casei suitable for plasmid DNA isolation

Lactobacillus casei had a typical morphology (short rods) in complex medium but lost its rod form when grown in a minimal basal medium. Atypical morphologies were very fragile since they were lysed by treatments with 1% SDS and 1mg/ml proteinase K but they were efficiently used for plasmids isolation without treatment with phenol.