抄録
An improved method for regenerating Bacillus subtilis protoplasts at the frequency of 92-100% on a semi-synth tic medium was found. Protoplasts were preincubated in HCP-3 medium, an isotonic semi-synthetic medium supplemented with polyvinylpyrrolidone, and then plated on HCP-1.5 agar medium by overlaying. By this method, even on the regeneration medium supplemented with minimal nutritional requirements protoplasts regenerated at a frequency of as high as 20%. The modified method was applicable to the direct-selection of prototrophic recombinants after fusion (the highest recombination yield from the input protoplasts was 1.3%) and to protoplast transformation with plasmid DNA.
