Development of a low-cost inoculum to improve composting of cattle slaughterhouse by-products

The composting process is an option for acceptable environmental management of cattle slaughterhouse by-products. The goals of this article were (i) to make a low-cost inoculum using popular supermarket ingredients and microorganisms that are already present in the composting environment, and (ii) to compare the efficiency of the composting process with and without the application of formulated inoculum. Initially, a consortium of microorganisms already present in the composting environment (Saccharomyces cerevisiae, Bacillus subtilis, and Rhodopseudomonas palustris) was prepared in a low-cost culture medium for use as an inoculum for the composting process. The composting process with the addition of the inoculum was more efficient than the composting process without the inoculum, in terms of both the chemical composition and the process efficiency, but mainly in relation to the time required for composting, with the mean times for decay of 50% of the windrows' temperature (taking in to account the difference between internal and external windrow temperatures) being 96 days without inoculum and 65 days with inoculum. Thus, inoculum made with low-cost supermarket products reduced the composting time and yielded compost of better quality.