Optimization and bioactivities of beta glucan extracted from Pleurotus ostreatus cultivated on germinated riceberry rice (Oryza sativa)

Abstract

Beta-glucan (β-glucan), a polysaccharide recognized for its prebiotic effects and potential to inhibit colon cancer cell proliferation, is derived from sources like grains (β-1,3/1,4-glucan) and fungi (β-1,3/1,6-glucan). This study focused on optimizing the co-culture of germinated Riceberry rice with Pleurotus ostreatus mycelium to enhance the yield of this valuable bioactive compound. Optimal conditions for beta-glucan production were achieved after 9 days of co-cultivation, resulting in a substantial yield of 222.94 ± 2.33 mg/g of dried Riceberry rice. The extracted β-glucan was confirmed as a β-1,3/1,6-glucan using FTIR spectroscopy. Biological activity assessment demonstrated the extract's promising prebiotic properties, significantly promoting the growth of Lacticaseibacillus rhamnosus and Bacillus coagulans, as indicated by their respective Prebiotic Indices (6.36±0.72 and 115.70±10.19) and Prebiotic Activity Scores (0.56±0.03 and 1.39±0.06). Notably, the extract exhibited potent anti-colorectal cancer activity in vitro, inhibiting 66.23% of SW480 cell growth at a concentration of 1 mg/mL, a more pronounced effect than observed with standard beta-glucan and 5-fluorouracil. Additionally, the extract induced a significant level of apoptosis (28.91%) in these cancer cells. The formulated beta-glucan extract shows strong nutritional value, reinforcing its role as a promising health-promoting and anticancer nutraceutical.