| Pleurotus ostreatus has the characteristics of high lignocellulose degradation rate and lignocellulose enzyme activity. The breeding technique of protoplast mutagenesis is an effective method for edible fungi breeding. In order to use straw, which is a kind of renewable resources of great significance, more effectively, straw-degrading strain breeding of Pleurotus ostreatus was studied by using protoplast regeneration and UV mutagenesis techniques.The optimal conditions of protoplast output and regeneration was as follows:The lytic enzyme solution containing mixture of 1%(W/V) Cellulase andl%(W/V) Snailase; the volume ratio of Cellulase and Snailase was 1.5:1;using 0.6mol/L MgSO4 as osmotic stabilizer, the mycelium being incubated for 96 hours, and enzymatic time for 1 hour at 30℃;using 0.6 mol/L mannitol as regeneration osmotic stabilizer and MYG as regeneration medium.Under the optimization system, the yield rate and regeneration rate of Pleurotus ostreatus has been enhanced dramaticly:reaching 20.60×104 n/mg and 3.7%, respectively.After the protoplast was induced by ultraviolet radiation, the strain 08P217 was obtained and it's lignocellulose enzyme activity were much higher than that of the original strain. The degradation rates of lignin, cellulose, and hemicellulose of 08P217 were 1.75,1.71,3.22 times as much as those of the original strain, respectively. Comparing with the original strain, the yield increase rate of 08P217 was 10.3% in the fruiting experiment using wheat straw as the main culture substrates. Study on esterase isoenzyme showed that 08P217 was a new variant strain, which is different from the original strain, because there were some differences in their esterase isoenzyme pattern.By analyzing the biological efficiency in the fruiting experiment, we concludede the best doses of wheat straw in culture medium of 08P217 was 40%.Stability test showed that 08P217 was genetieally stable, and its application is feasible. |
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