Influence of low-intensity artificial light on the fatty acid profile of the biotechnologically important culinary mushroom Pleurotus eryngii in vitro.

Background: The problem of searching for environmentally friendly regulators of the biosynthetic activity of edible and medicinal mushrooms is crucial for creating highly effective biotechnologies. One such regulator is light. This study aimed to compare and evaluate the fatty acid profile and fat quality indices of lipids from the mycelial mass of Pleurotus eryngii under various light-emitting diode (LED) and laser light irradiation regimes.

Methods: To determine the effect of artificial light on the biosynthetic activity of P. eryngii, an artificial lighting system based on LED matrices with wavelengths of 470 nm (blue), 530 nm (green), and 650 nm (red), as well as an argon gas laser as a coherent visible light source at 488 nm, was used. For all experimental variants, the energy density on the surface of the samples was set to the same, providing an energy dose of 240 mJ/cm². Irradiation was carried continuously.

Results: Twenty-seven fatty acids were identified in the studied P. eryngii mycelial mass samples, including nine saturated fatty acids (SFAs), eight monounsaturated fatty acids (MUFAs) and ten polyunsaturated fatty acids (PUFAs). The control sample (without irradiation) contained the lowest number of fatty acids (fourteen). With irradiation in all modes, a decrease in the amount of SFA and the formation of new MUFA and PUFA with a chain length of C20-C24, which were absent in the control, were observed. Blue light stimulated the synthesis of significant amounts of α-linolenic acid (C18:3ω-3). The ratios of ΣPUFA/ΣSFA, ΣPUFA/ΣMUFA and ΣPUFAω-6/ω-3 in the mass of mycelium irradiated with blue light were within the optimal values for the human diet.

Conclusions: The selected mycelial photoactivation modes using low-intensity laser and LED light of different spectral composition and coherence may have potential in the biotechnology of submerged cultivation of P. eryngii to obtain mycelial mass with an improved fatty acid profile, which can be considered as a useful source of lipids.