TRANSFORMATION OF BACILLUS-LICHENIFORMIS PROTOPLASTS BY PLASMID DNA

A simple and efficient protoplast regeneration and PEG-induced transfo rmation procedure was developed for Bacillus licheniformis. The protop last stabilizing osmoticum was 0.5 M sucrose in the regenerating media , and the restoration of cell wall was carried out at pH 8.4. The mean frequency of regeneration was 83%. The transformation efficiency was studied with four different strains and five plasmids, and ranged from 3.5 x 10(5) to 7.2 x 10(6) transformants per mu g plasmid DNA dependi ng on the plasmid, and on the donor and recipient strains used. Endonu clease digested and ligated plasmid DNA could also be used to transfor m the protoplasts, but at a lower frequency.