Photoregulation of the biosynthetic activity of the edible medicinal mushroom Lentinula edodes in vitro.

The findings of the study demonstrate the impact of low-intensity laser and quasi-monochromatic light on the biosynthetic activity of the edible medicinal fungus L. edodes during submerged cultivation. An artificial lighting installation based on matrices of light-emitting diodes (LED) emitting light at 470 nm (blue), 530 nm (green), 650 nm (red), and argon gas laser (488 nm) was used. Irradiation with blue and red LED and laser led to a shortening of the lag phase by 2 days and an increase in the mycelial mass. Irradiation with laser light resulted in the highest mycelial mass yield (14.1 g/L) on the 8th day of cultivation. Irradiation in all used wavelength ranges caused an increase in the synthesis of both extracellular and intracellular polysaccharides. Laser light at 488 nm and LED at 470 nm proved to be the most effective. Irradiation with red, green, and blue laser light caused an increase in the total amount of fatty acids in the mycelial mass compared to the control. A significant distinction in qualitative composition was observed: short-chain acids C6‒C12 compounds were produced under red light irradiation, whereas long-chain C20‒C24 were formed under green light irradiation. The most significant changes in the aromatic profile of the mycelial mass and culture liquid were recorded upon irradiation with green light. The content of aromatic components increased 24.6 times in the mycelial mass and 38.5 times in the culture liquid. The results suggest the possibility of using low-intensity quasi-monochromatic light for targeted regulation of L. edodes biosynthetic activity.

Effect of Colloidal Metal Nanoparticles on Biomass, Polysaccharides, Flavonoids, and Melanin Accumulation in Medicinal Mushroom Inonotus obliquus (Ach.:Pers.) Pilát.

The article explores effect of colloidal nanoparticles (NPs) of Ag, Fe, and Mg metals on the growth activity of the medicinal mushroom Inonotus obliquus (Ach.:Pers.) Pilát and the synthesis of biologically active compounds (polysaccharides, flavonoids, and melanins). It was found that all the studied NPs stimulated growth activity. AgNPs inhibited polysaccharide and flavonoid synthesis, and stimulated melanin synthesis by 140%. Using MgNPs was effective to increase the level of accumulation of endopolysaccharides, flavonoids, and melanin pigments. FeNPs significantly increased the yield of endopolysaccharides. This effect should be used for biosynthesis stimulation for polysaccharides, flavonoids, and melanins obtaining from I. obliquus cultivated in vitro. The results demonstrate the potential of the use of metal colloidal solutions NPs for the development of environmentally friendly and effective biotechnology to produce biologically active compounds by medicinal macromycete I. obliquus.

Effect of Light Wavelengths and Coherence on Growth, Enzymes Activity, and Melanin Accumulation of Liquid-Cultured Inonotus obliquus (Ach.:Pers.) Pilát.

To investigate effects of light wavelengths and coherence on growth of liquid-cultured Inonotus obliquus mycelia, melanin accumulation and enzymes activity, culture condition as light of different wavelengths and coherence were studied. Short-term exposure of the vegetative mycelium by low-intensity coherent blue light was optimal for stimulation of growth, melanin synthesis, and increase in extracellular and intracellular activities of tyrosinase and polyphenoloxidase and extracellular catalase. Red coherent light, in the same mode, can effectively be used to stimulate the growth of mycelium and to increase intracellular and extracellular activity of polyphenoloxidase, extracellular catalase and tyrosinase, and intracellular peroxidase. Low-coherent light had less stimulating effect on the biosynthetic activity of I. оbliquus. It should be used in the cultivation directed at the obtaining endomelanin, polyphenoloxidase, and extracellular tyrosinase.