An efficient method for the preparation of protoplasts fromTrichoderma viride

Regeneration and molecular characterization of an intergeneric hybrid between Graphium putredinis and Trichoderma harzianum by protoplasmic fusion

The fungal strains Graphium putredinis and Trichoderma harzianum were selected as parents for fusant development. Protoplasts were isolated using the combination of lysing enzymes Novozym 234 and cellulase with 0.6M KCl as osmotic stabilizer. The optimum conditions for release of viable protoplasts from the fungal mycelium viz. age of the mycelium, lytic enzymes, osmotic stabilizers, pH, incubation period and regeneration medium were determined. Intergeneric protoplast fusion was carried out using 50% polyethylene glycol with calcium chloride (CaCl(2)) and glycine buffer and the conditions for effective protoplast fusion, viz. fusogen, osmotic stabilizer, pH, incubation period and regeneration medium were optimized. At optimum conditions, the regeneration frequency of the fused protoplasts on potato dextrose agar (PDA) medium and fusion frequency were calculated. The regeneration frequency on non-selective (PDA) and selective media (PDA amended with starch) was determined for the parental and fusant strains in which, fusant showed a higher rate of regeneration. Fusant formation was confirmed by morphological markers (colony morphology and spore size and shape) and genetical markers like, mycelial protein pattern, restriction digestion pattern and random amplified polymorphic DNA (RAPD) analysis. The efficiency of these parental strains and their intergeneric fusant in the production of hydrolytic enzymes - amylases (treatment plant for sago factory effluent), cellulases (bioethanol), xylanases (bleaching agents for waste paper pulp) and proteases (additives in commercial detergents) - have probable applications in various industrial processes.

Release and regeneration of protoplasts from the fungus Trichothecium roseum

A protocol for isolating and regenerating protoplasts from Trichothecium roseum has been described. Protoplasts from T. roseum were isolated using (i) a lytic enzyme combination composed of Novozym 234, chitinase, cellulase, and pectinase at a 5-mg/mL concentration and (ii) 0.6 M KCl as an osmotic stabilizer. A maximum number of 28 x 10(4) protoplasts/mL were obtained at pH 5.5. Experiments on the regeneration and reversion of protoplasts revealed a maximum regeneration (60.8%) in complete medium (potato dextrose--yeast extract agar) amended with 0.6 M KCl. The regenerated protoplasts were similar to the original parent strain in morphology, pigmentation, growth, and sporulation.