Microbiological characteristics of compost produced from dairy and wine by-products

Abstract

Wine and dairy chains rapresent of the agri-foof leading sectors in Sicily. Composting residues from these two chains would contribute to increase the environmental sustainability of the production with additional advantages represented by the reduction the costs recover soil fertility. This work represents the first attempt to combine the green of the vine cultivation as well as wine and dairy by-products. Raw materials provided potential bioactivators identified as Bacillus subtilis, Bacillus velezensis and Kocuria rhizophila which showed cellulolytic activity. The strain were inocultated in the mass to be composted in order to accelerate the process. Four compost trials were performed: (i) absence of boactivators and mainteinace of umidity with deproteinized whey; (ii) presence of bioactivators and mainteinace of umidity with deproteinized whey; (iii) absence of boactivators and mainteinance of umidity with water; (iv) presence of bioactivators and mainteinace of umidity with water. The experiment lasted 105 days, during which environmental parameters, such as temperature and umidity were monitored. Growth dynamics of the principal functional groups of mesophilic and thermophilic microorganisms were followed. The composting process was monitored during the entire period through the detection of physical-chemical (pH, humidity, TOC, humic acid + fulvic acid, TN, Org-N, C/N, S, Cd, Cr, Hg, Ni, Pb, Cu, Zn) and microbiological parameters (Salmonella spp., Escherichia coli). The characteristics of all composts fulfilled the requirements of the Italian legislation for ther use to amendt soil. Furthemore, germination tests demonstrated the absence of phytotoxicity against Lepidium sativum L..