Pathways and mechanisms of improving carbon and nitrogen conversion by core fungal community driven during co-composting of spent mushroom substrate and corn steep liquor

Abstract The aim of this study was to revealed the core fungal mechanisms for the transformation of carbon (C) and nitrogen (N) during co-composting of spent mushroom substrate(SMS) and corn steep liquor (CSL) process. There were two treatments: CK (fully SMS) and CP (CK + 0.5% CSL). The results indicated that the core fungi, fungal community structure and fungal diversity were the main driving forces for the transformation of C and N during composting. The rich nutrition in CSL changed fungal community structure, increased the abundance and diversity of fungi in the early stage, but decreased in the late stage of composting, promoted the conversion and conservation of C and N in composting. Core fungus in the C and N transformation were identified. The compensating effects of core fungi were encouraged in CP composting. The influence of core fungus on the C and N conversion could be divided into two pathways in CP, One was that core fungi promoted organic C and N degradation by increasing the abundance and diversity of fungi; while the other was promoted the the synthesis of organic C and N by the complementarity effects of core fungal, contribute to the C and N conservation in compost. These findings showed that the addition of CSL to composting was a promising application to treat SMS with lower C/N ratio.