CHEMICALLY INDUCED MUTAGENESIS IN THE KING OYSTER MUSHROOM Pleurotus eryngii TO GENERATE HIGH-TEMPERATURE TOLERANT STRAIN

In this study, a high-temperature-tolerant strain of the king oyster mushroom (Pleurotus eryngii) was generated by chemical mutagenesis. Cultivation of P. eryngii generally involves incubating the mycelia at 25°C and then moving the spawns for further incubation at 18°C for fruitification. However, in tropical countries, the temperature is a major concern in the production of oyster mushroom where the average temperature is 32°C. In the current study, the mycelia were treated with ethyl methane sulphonate (EMS) or methyl methane sulphonate (MMS) for chemical-induced mutation. Seven mutants (EMS 1, 2, 6, 26, 35, 36, and 38) from EMS mutagenesis exhibited higher growth rates than the wild-type strain at 32°C. However, mutant strains from MMS mutagenesis showed a low growth rate when compared with wild-type. On sawdust substrate, the spawn running conditions for these strains were performed at 32°C, and fruitification occurred at 18°C. The yield and biological efficiency of EMS 36 and 38 mutants were higher than those of the wild-type strain. The activities of cellulase and xylanase of EMS 36 and 38 mutants showed that both these mutants had higher activities than the wild-type strain which may influence mushroom production. Therefore, these EMS 36 and 38 mutants can be cultivated in tropical countries, which could provide a high yield and reduce the cost during spawn running step.

OPTIMIZATION OF KING OYSTER MUSHROOM (PLEUROTUS ERYNGII) PRODUCTION AGAINST COTTON WASTE AND FENUGREEK STRAW

King oyster (Pleurotus eryngii) mushroom is a palatable mushroom with high commercial potential due to relative ease of its growing technology, less cost of production and better yield potential, making it popular throughout the world. Therefore, an experiment was set up to assess the efficacy of different agro-wastes [cotton waste (CW) and fenugreek straw (FS)] on the morphology, yield and nutritional components of two strains (Pleurotus eryngii P9 strain and Pleurotus eryngii P10 strain) of Pleurotus eryngii. Studied indicators regarding time for pinhead formation, fruiting body development, biological efficiency and yield of both strains were significantly affected by different formulations of substrates. Substrates with 100 % CW exhibited maximum number of pinheads, yield and biological efficiency for both strains of king oyster as compared to other substrates alone or in mixture. This experiment indicates the possibility of Pleurotus eryngii cultivation on cotton waste and fenugreek straw in controlled conditions for enhanced growth and yield.