Improvement of Cellulolytic Activity of Pleurotus florida through Radiation Mutagenesis

A mushroom mutant with increased cellulolytic activity was developed through radiation mutagenesis. The homogenized hypha suspension of Pleurotus florida was exposed to gamma radiation ($^{60}Co$, AECL) at the dose of $LD_{99}$ (0.51 kGy, $D_{10}$; 0.26 kGy). Among 16 mutants, Pf CM4 showed 17.24% more cellulolytic activity than the wild type (p<0.05). It was observed that Pf CM4 can utilize all kinds of carbon sources tested for their mycelia growth. Starch, xylan, and glucose favourably supported the radial mycelia extension. Yeast extract and $NH_4NO_3$ have been recorded as the best organic and inorganic nitrogen sources, respectively. Pf CM4 was found to grow significantly faster, even at high temperature ($30^{\circ}C$), than wild type (p<0.05), and the optimal pH was 5.5~6.5. This study reveals that the mutant Pf CM4 could be employed for the effective recycling of cellulosic wastes, in addition to mushroom farming.