Selenium Biofortification of Pleurotus Mushrooms and Utilization of Spent Waste for Vermicomposting: A Sustainable Approach for Circular Agriculture

Background: Agro-wastes represent valuable resources for mushroom cultivation, particularly Pleurotus species, which offer significant nutritional benefits and are grown using cost-effective methods. Selenium (Se), an essential micronutrient crucial for human health, is vital for preventing various diseases. Sodium selenite has emerged as an effective method for increasing selenium levels in mushrooms, thereby enhancing their nutritional quality. Additionally, utilizing biofortified spent mushroom waste for vermicomposting presents a sustainable solution for recycling organic waste and improving soil fertility. Methods: This study examines the biofortification of three Pleurotus species by applying sodium selenite in paddy straw substrate. The research investigates selenium accumulation and its impact on yield and biological efficiency, in addition to assessing various biochemical parameters. Furthermore, the study explores the influence of selenium-biofortified spent mushroom waste on the growth of earthworms during the vermicomposting process. Result: Our investigation into the biofortification of mushrooms with selenium revealed that incorporating 5% of sodium selenite into the substrate significantly enhanced the selenium content of Pleurotus ulmarius (CO2), Pleurotus florida and Pleurotus eous (APK1). However, increasing selenium content in the substrate correlated with decreased biological efficiency. Selenium biofortification resulted in a noteworthy increase in protein content alongside a reduction in carbohydrate levels. Moreover, utilizing selenium-biofortified spent mushroom waste (SeSMS) at a concentration of 2.5% in combination with cow dung (1:10) yielded favorable outcomes, including enhanced cocoon production and the presence of young and adult worms during vermicomposting on both the 60th and 90th day.