Change in agrochemical and biochemical parameters during the laboratory vermicomposting of spent mushroom substrate after cultivation of Pleurotus ostreatus

Abstract

Pleurotus ostreatus is one of the most cultivated mushrooms in the Czech Republic. The production of 1 kg of mushrooms generates about 5 kg of spent mushroom substrate. A gentle and fast method for using this substrate is vermicomposting. Vermicomposting of spent mushroom substrate using Eisenia andrei was conducted for seven months. For control purposes, a treatment without earthworms was also prepared. The vermicomposting process used vertical continuous feeding vermicomposters. The agrochemical and biological parameters were analysed. Values of electrical conductivity were very high in both vermicomposters (higher than 2000 μS/cm). During the vermicomposting process the C/N ratio decreased. The number and biomass of earthworms decreased with the age of the layers. The values of total P, K and Mg were higher in the vermicomposter without earthworms. There were also lower microbial phospholipid fatty acids content - than in the vermicomposter with earthworms. However, the fungal phospholipid fatty acids content were two times higher in the vermicomposter without earthworms. The highest hydrolytic enzyme activity was found in lipase, acid phosphatase and β-D-glucosidase. Most hydrolytic enzymes were more active in the vermicomposter without earthworms, with the exception of arylsulphatase. Mn-peroxidase activity was higher in the vermicomposter without earthworms and laccase activity was below the detection limit.