Turn Waste into Treasure: Spent Substrates of Auricularia heimuer Can Be Used as the Substrate for Lepista sordida Cultivation

Abstract

Mudanjiang is a major producer of black wood ear (Auricularia heimuer) mushrooms in China. It has been estimated that more than 1.5 million tons of spent substrates of A. heimuer (SSA) are produced each year. Most of these are discarded or burned and have become an important source of pollution, which urgently merits research to find appropriate uses for them. To explore the feasibility of SSA as a substrate for cultivating Lepista sordida mushrooms, experiments were conducted to assess the effects of the addition of 0, 40%, 73%, and 98% SSA on the days required for the mycelia to fully colonize the substrate and initiate primordia, biological efficiency (BE), yield, and composition of the chemical biomass of the L. sordida fruiting bodies. The yield of fruiting bodies with 0, 40%, 73%, and 98% SSA supplementation for three flushes was 3.90 ± 0.74 kg m−2, 4.06 ± 0.77 kg m−2, 4.03 ± 0.62 kg m−2, and 4.51 ± 0.65 kg m−2, respectively. The addition of 98% SSA significantly delayed the number of days for the mycelia to fully colonize and form primordia by 6 and 3 d, respectively. This treatment also significantly increased the yield and BE by 15.64% compared with that of the control group. The crude polysaccharide content of 25.64 ± 0.38 g 100 g−1 was higher in the samples grown on the 98% SSA substrate, which was shown to increase by 78.93% compared with that of the control substrate with 73% corn straw (14.33 ± 0.03 g 100 g−1). The content of crude protein of 51.10 ± 0.08 g 100 g−1 was higher in the samples grown on the 40% SSA substrate, which increased by 11.14% compared with the protein content of the control group. This study reveals that SSA would be a good substrate for the cultivation of L. sordida and is an efficient, promising, and cost-effective substrate additive that can improve the quality and yield of these mushrooms, while substantially reducing the problems of disposing of SSA.