Protoplast Formation and Regeneration of Clostridium acetobutylicum Strain N1-4080

SUMMARY: A method for the production of protoplasts of Clostridium acetobutylicum strain N1-4080 utilizing lysozyme and penicillin G was optimized to yield about 100% protoplasts. Treatment of 109 cells left fewer than 102 that were viable and osmo-resistant. With a mutant strain deficient in autolytic activity, about 1% of the protoplasts regenerated walled cells, whereas most gave rise to stable L-form colonies. Addition of sodium polyanethole sulphonate to the medium improved the regeneration frequency by at least a factor of 10, probably by somehow inhibiting the residual autolytic activity of the strain.