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

Ballardo, Cindy, Barrena, Raquel, Artola, Adriana, Sánchez, Antoni
Waste management 2017 v.70 pp. 53-58
Bacillus thuringiensis, biodegradability, biopesticides, cell viability, composts, municipal solid waste, soil amendments, solid state fermentation, spores, value-added products, waste management
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 1.7·10⁷–2.2·10⁷ and 1.3·10⁷–2.1·10⁷ 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.