Factors affecting protoplast release from some mesophilic, thermophilic and thermotolerant species of filamentous fungi using Novozym 234.

Factors affecting the release of protoplasts from mycelia of Aspergillus fumigatus, Aspergillus niger, Penicillium ochrochloron and Geosmithia emersonii were investigated. Protoplast yields were found to be greatly dependent on the growth temperature, incubation conditions, lytic enzyme system, mycelial age and mycelial concentration. High yields of protoplasts were obtained from all four organisms after a 3 h incubation with 1 mg/ml Novozym 234 in 0.1 M 2-N-[morpholino] ethane sulphonic acid (MES) buffer at pH 5.0, containing 0.6 M sodium chloride. Supplementation of the incubation medium with 0.03 M calcium chloride enhanced protoplast release in P. ochrochloron but not in the other three fungi.