Growth of mycelium of different edible and medicinal mushrooms on medium supplemented with digestate from AD biogas plant

Abstract

Digestate is remaining material after anaerobic digestion (AD) of a biodegradable feedstock. The AD process produces two main products: digestate and biogas; digestate is considered as a waste; however, it found application in agriculture i.e. as a soil conditioner or cultivation substrate component. Digestate is rich in nitrogen and phosphorus and can be used as a substrate component for mycelial growth of mushrooms. Aim of the study was examination of agar media supplementation with digestate from AD of foodwaste material on mycelial growth of cultivated and medicinal mushrooms. Mycelial growth of four mushroom species was investigated: Coprinus comatus, Ganoderma lucidum, Agaricus subrufescens and Laetiporus sulphureus. First experiment investigated four mushroom species and 3 digestate-only based agar media with growing amount of digestate extract. Later fastest growing mushrooms from exp. 1, C. comatus and G. lucidum, was chosen, mycelial growth was performed on 2 digestate-only based agar media and 2 what/digestate extract based agar media. Wheat-based and manure-based agar media was used as control medium. Study confirmed positive effect of digestate from AD as an addition or main component of agar media culture for mushroom mycelium growth. The amount of digestate extract affected mycelial growth of investigated species. The best agar media was digestate-based only with 25 g of extract and wheat/digestate based (150/50 g extract). The fastest and the best growth were obtained for C. comatus. The residue from AD biogas production could have found additional application as media product for mushroom mycelia production and further as a component for mushroom cultivation substrate.