Protoplast formation,regeneration and fusion in Bacillus polymyxa

Two-hour lysozyme treatment (1 mg/ml) of mid-logarithmic phase Bacillus polymyxa cells at 37°C resulted in 99% protoplasting efficiency. Among three typical regeneration media, HCP 1.5 gave the highest regeneration frequency of 1.8 × 10⁻². Protoplast fusion between B. polymyxa B1103 Str⁺ His and B1104 Tyr⁻ produced 39.6% recombinants of the total regenerants, Str^r His⁺ Tyr⁻ and Str^r His⁻ Tyr⁻ being the major recombinant phenotypes.