Utilisation of solid digestate from acidification reactors of continues two-stage anaerobic digestion processes in Lentinula edodes cultivation

Abstract The edible fungus Lentinula edodes was cultivated on growth substrates containing solid digestate (press cake) from hydrolysis steps of hay and straw digestion in two-stage anaerobic digestion processes. Chemical analyses uncovered modifications of nitrogen and carbon uptake affecting the mycelial growth and fruiting of L. edodes under press cake application. Inhibition of metabolic processes was revealed in substrates containing ≥60% PC. The application of 40% press cake led to the highest loss of dry mass from growth substrate, the highest degradation and metabolism of lignocellulosic polymers, and the strongest quality of mushrooms harvested, as measured by vitamin content (+74% compared to conventional growth substrate) and mushroom yield (+35% compared to conventional growth substrate). These observations suggest new innovative pathways for digestate utilisation, and indicate that lignocellulose-rich press cakes from biogas plants are valuable substrates for cultivations of L. edodes.