MYCOLab Ai Logo - gold and army green

Impact of bottom ash addition on Pleurotus ostreatus cultivation on coffee ground substrate

Summary

This study investigated growing oyster mushrooms on a mixture of used coffee grounds and coal plant bottom ash. The researchers found that adding small amounts of bottom ash (1-5%) slowed mushroom growth slightly but actually reduced harmful heavy metals in the final mushrooms compared to using only coffee grounds. The leftover substrate after mushroom harvest could be used as a fertilizer for poor soils, creating a complete recycling system that turns industrial and food waste into useful products.

Background

Pleurotus ostreatus is the second most widely cultivated edible mushroom and can grow on agricultural and food waste materials. Spent coffee grounds are suitable substrates for mushroom cultivation, representing an innovative recycling approach. Bottom ash from coal-fired power plants contains high concentrations of heavy metals and requires safe disposal, making its potential use in agriculture relevant for circular economy applications.

Objective

This study aimed to explore the potential use of coal-fired power plant bottom ash in Pleurotus ostreatus cultivation using spent coffee grounds as substrate. The research also evaluated the accumulation of heavy metals and other elements in mushrooms and post-cultivation substrates at different bottom ash concentrations (1%, 5%, and 10%).

Results

Addition of 1% bottom ash did not affect mycelium growth but slowed fruiting body development by 4 days; 5% addition slowed both by 6-7 days; 10% completely inhibited growth. Fruiting bodies from 1% bottom ash substrate contained higher phosphorus, copper, and zinc while showing lower chromium, nickel, and lead accumulation compared to coffee grounds alone. Post-cultivation substrates showed enriched nutrient content suitable for soil amendment purposes.

Conclusion

Bottom ash addition at 1-5% concentrations shows promising potential for mushroom cultivation on spent coffee grounds while reducing heavy metal accumulation in fruiting bodies. The post-cultivation substrates demonstrate improved nutrient content and could serve as soil amendments or fertilizers for depleted soils. Further safety assessments are required before larger-scale implementation for human consumption or agricultural use.
  • Published in:Scientific Reports,
  • Study Type:Experimental Study,
  • Source: 10.1038/s41598-024-83434-z, PMID: 39738424
Scroll to Top