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

Abstract

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 NH 4 + -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 log 10 CFU g −1-dw, 1.2–4.3 log 10 MPN g −1-dw, 3.5–6.8 log 10 MPN g −1-dw, 3.58–4.34 log 10 MPN g −1-dw, 1.4–3.8 log 10 MPN g −1-dw, and 4.2–8.8 log 10 CFU g −1-dw higher in the compost inoculated with P. expansum.