Regeneration of yeast protoplasts prepared using Novozym 234.

Novozym 234 (Novo lndustri A/S, Bagsraerd, Denmark) is a comparatively cheap and highly effective commercial preparation, derived from the fungus 7richoderma harziunum, which is used for the enzymic degradation of the cell wall in many yeasts and filamentous fungi in order to release protoplasts [ 1 , 21. The factors involved in protoplast isolation using this system have been investigated by Collings et al. [3]. The regeneration of the protoplast cell wall and concomitant reversion to normal growth and morphology is a prerequisite for fusion and transformation studies. Factors affecting the regeneration of such Novozym 234-prepared protoplasts are addressed here.