Enhanced production and antioxidant activity of endo-polysaccharides from Phellinus igniarius mutants screened by low power He-Ne laser and ultraviolet induction

In this study, a Phellinus igniarius mutant was screened through low power He-Ne laser and ultraviolet (UV) induction. The mutant was then used to improve the production of endo-polysaccharides. In the shake flasks, the dry weight of the mycelial biomass and the production of endo-polysaccharides derived from the screened mutant (JZx) fermentation were 20.715 g/L and 1.428 g/L, respectively, which were 40.31% and 56.58% higher than those of the control strain (CK). In addition, isozyme electropheresis spectrogram analysis results indicated that the genetic materials of the screened mutants were altered. The endo-polysaccharides obtained from the JZx fermentation were mainly composed of D-glucose, L-rhamnose, and D-mannose in a molar ratio of 2.0:16.0:1.0 and with low-molecular weights (MWs) (1.5 kDa, 61%). These endo-polysaccharides exhibited stronger antioxidant activities in vitro, contained stronger hydroxyl radical scavenging capacity, and higher Trolox equivalent antioxidant capacity (TEAC) (195.43 μmol Trolox/g sample) and ferric reducing ability of plasma (FRAP) (20.57 μmol Fe2+/g sample) values compared with those of the CK. Therefore, the mutant screening through low power He-Ne laser and UV-induction could be an efficient and practical method for the development of the Phellinus strains and thus could improve the production and antioxidant activities of their endo-polysaccharides.