Effect of inoculation with Penicillium expansum on the microbial community and maturity of compost

Compost prepared from wheat straw and cattle/chicken mature was inoculated with the lignocellulolytic fungus, Penicillium expansum. Compared to uninoculated compost, the inoculated compost exhibited a 150% higher germination index, more than 1.2 g kg−1-dw of changes in NH4+-N concentrations, a ca. 12.0% higher humus content and a lignocellulose degradation that proceeded 57.5% faster. Culture-based determinations of microbial populations demonstrated that aerobic heterotrophic bacteria and fungi were about 1–2 orders of magnitude higher in inoculated than in uninoculated compost. The number of ammonifying, ammonium-oxidizing, nitrite-oxidizing, denitrifying bacteria and cellulose-decomposing bacteria was 6.1–9.0 log10 CFU g−1-dw, 1.2–4.3 log10 MPN g−1-dw, 3.5–6.8 log10 MPN g−1-dw, 3.58–4.34 log10 MPN g−1-dw, 1.4–3.8 log10 MPN g−1-dw, and 4.2–8.8 log10 CFU g−1-dw higher in the compost inoculated with P. expansum.

► Pretreatment of wheat straw and cattle/poultry mature with lignocellulolytic fungi is necessary.
► Penicillium expansum, a lignocellulolytic fungus, improves the quality and maturity of compost.
► Compost treated with P. expansum   increase germination index, humus content, and decrease NH4+-N level.
► P. expansum increased the degradation ratio of hemicellulose, cellulose and lignin of wheat straw.
► P. expansum significantly influenced the microbial communities during composting process.