A novel strategy for producing compost with enhanced biopesticide properties through solid-state fermentation of biowaste and inoculation with Bacillus thuringiensis

In the framework of a circular economy, organic solid wastes are considered to be resources useful for obtaining value-added products. Among other potential uses, biodegradable wastes from agricultural, industrial, and domestic sources are being studied to obtain biopesticides through solid-state fermentation (SSF), mainly at the laboratory scale. The suitability of biowaste (source-selected organic fraction of municipal solid waste) for use as a substrate for Bacillus thuringiensis (Bt) growth under non-sterile conditions in a 10 L SSF reactor was determined in this study. An operational strategy for setting up a semi continuous process yielding a stabilised organic compost-like material enriched with Bt suitable for use as a soil amendment was developed. Concentrations of 1.7.10(7)-2.2.10(7) and 1.3.10(7)-2.1.10(7) CFU g(-1) DM for Bt viable cells and spores, respectively, were obtained in the final material. As the results confirmed, Bt-enriched compost-like material with potential biopesticide properties can be produced from non sterile biowaste. (C) 2017 Elsevier Ltd. All rights reserved.