Enhancement of water-soluble polysaccharide extraction yield from the industrial exhaustive extracted spent of Ganoderma lucidum biomass by combination of gamma irradiation and hydrogen peroxide treatment

Objective The industrial exhaustive extracted spent of G. lucidum biomass was irradiated in the presence of hydrogen peroxide to improve the recovery of water-soluble and high biological activity polysaccharides. Methods The spent G. lucidum biomass was irradiated at 10 and 20 kGy in 2% hydrogen peroxide before extraction to obtain water-soluble polysaccharides. The structural characteristics of the extracted polysaccharides were analyzed by gel permeation chromatography, Fourier transform infrared spectroscopy, X-ray diffraction, and high-performance anion-exchange chromatography with pulsed amperometric detection. The in vitro antioxidant activity and antiproliferative effects against A549 lung cancer cells were evaluated using the 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, respectively. Results The spent G. lucidum biomass irradiated at 10 kGy achieved the highest extraction yield and contents of total polysaccharide (84.9%) and β -glucan (44.3%). In addition, the FTIR and XRD analyzed results revealed that the structural characteristics the water-soluble polysaccharide extrated from spent G. lucidum biomass irradiated at 10 kGy are similar to the sample extracted from unirradiation spent G. lucidum biomas. However, differences in the types and proportions of constituent monosaccharides were still observed. Furthermore, the water-soluble polysaccharide extrated from spent G. lucidum biomass irradiated at 10 kGy exhibited relatively high radical-scavenging activity and protein peroxidation-inhibitory capacity, with IC 50 values of about 68.34 and 407.33 μg/mL, respectively. In addition, this sample also exhibited a strong dose-dependent inhibitory activity against A549 cell proliferation while showing a none toxicity toward normal cells (L929). Conclusions The application of γ-ray irradiation in combination with hydrogen peroxide for treating G. lucidum discard waste to recover water-soluble polysaccharides with high antioxidant and anticancer effects boosts product value, efficiently utilizes waste within a circular economy model, and promotes green growth through waste minimization.