The Microbial Community in a Substrate of Solid-State Fermentation by Lentinula edodes: A Preliminary Study

Edible-fungal-based solid-state fermentation holds promise for sustainable food and biofuel production. Understanding the role of microbial communities in fungal substrates is crucial. Birch-based substrates were treated with autoclaving (121 °C, at 2 bar) or hot air pasteurization (75–100 °C), followed by incubation with and without shiitake (Lentinula edodes) inoculum. Mycelial growth was monitored by CO2 release and microbial biomass by phosphate-lipid fatty acid (PLFA). DNA sequencing was used to analyze the microbial communities. Results showed successful colonization of shiitake on all substrates, regardless of pasteurization temperatures and coexisting microbes. Total microbial respiration (CO2) and PLFA biomass showed no significant differences between pasteurization regimes. However, significant microbial differences were found between shiitake-inoculated and non-inoculated treatments. DNA sequencing revealed the dominance of Phyllobacterium, Sphingomonas, and Pelomonas genera in all inoculated substrates, while non-inoculated substrates were abundant in Bacillus spp. and Paenibacillus spp. of the Firmicutes phylum. This study provides preliminary insights into the microbial community in birch-based shiitake substrates, facilitating further investigation of bacteria involved in shiitake mycelium growth promotion and biochemical conversion for biofuel production.