Using spent mushroom substrate (SMS) as a casing boosted bacterial activity and enhanced the mineral profile of the Calocybe indica

Summary

Researchers tested using leftover mushroom material (spent mushroom substrate) as a growing medium for milky mushrooms instead of traditional loamy soil. While traditional soil produced more mushrooms overall, the mushrooms grown in the recycled substrate contained significantly higher levels of beneficial minerals like zinc, copper, and phosphorus. The study found that beneficial bacteria in the recycled material helped make nutrients more available to the mushrooms, making this approach both environmentally friendly and nutritionally advantageous.

Background

Calocybe indica is a summer-adapted mushroom variety suitable for tropical and subtropical regions with extended warm seasons. Casing is essential for its cultivation, traditionally using loamy soil (LS), a non-renewable resource. This study explored spent mushroom substrate (SMS) as a sustainable alternative casing material.

Objective

To evaluate SMS as an alternative to loamy soil for Calocybe indica cultivation by analyzing physio-chemical properties, bacterial composition, yield, biological efficiency, and mineral content of mushrooms grown on these substrates.

Results

SMS exhibited higher water-holding capacity, C/N ratio, and electrical conductivity compared to LS. Dominant bacteria in SMS included Bacillus, Priestia, and Lysinbacillus, which enhance temperature tolerance and phosphorus uptake. LS produced higher yield and biological efficiency, while SMS-grown mushrooms showed significantly elevated Cu, Zn, and P content, with notably higher phosphorus levels attributed to phosphorous-solubilizing bacteria.

Conclusion

Loamy soil remains more effective for maximizing yield, while SMS emerged as a sustainable alternative that enhances nutritional content of mushrooms. Calocybe indica is a hyperaccumulator of potassium and shows synergistic interactions between calcium and iron, making SMS a feasible choice for ecologically aware farming.
Scroll to Top