Pleurotus ostreatus cultivation for more sustainable soybean and sunflower seed waste management

Abstract

The seed and edible oil (SEO) industry produces a significant amount of waste, from wastewater to organic solid waste such as soybean and sunflower seed husks. The inclusion of these materials as substrates for edible mushroom production was examined. Lignocellulosic characterization of the substrates was also performed to determine the exact nutrient requirements for fungal inoculation. Comparative analysis with the control sample cultured on traditional wheat straw showed that the solid wastes of SEO not only allowed a satisfactory growth rate of Pleurotus ostreatus, but also resulted in fruiting bodies with satisfactory sensory characteristics, chemical composition, and functional properties such as antioxidant activity. For the first time, emphasis was placed on cytotoxic and genotoxic properties to obtain baseline data for risk assessment. The results show that the maximum shelf life of P. ostreatus that allows overall quality to be maintained is seven days, as there is a genotoxic risk if the mushrooms are stored longer. Although the biological efficiency was <50 %, the fruiting bodies produced showed excellent characteristics, with growth yield of 1114 g for soybean seed husk (SBN) substrate. The only limitation was the duration of storage, considering the leakage of electrolytes >23 % on the day 14 which leads to increased growth of psychrotrophic microorganisms (2.65–3.20 log CFU/g). Considering the resource-intensive SEO industry and the significant amounts of waste associated with it, incorporating waste streams from this industry and converting them into valuable food contributes toward the research-backed realistic new avenues and moves beyond the status quo of the SEO industry.