Disposal and utilization of dead animals during breeding in livestock and poultry farming by means of synthetic microbiota

Abstract

The disposal of animal remains resulting from breeding is a significant challenge that impacts the industry's growth. To address the issues with current treatment methods, such as the large space required for corpse storage, and the high energy consumption of pyrolysis. Three strains with high protease and lipase production and one strain with high keratinase production were screened. The virulence genes were evaluated, the synthesis gene clusters of degrading enzymes were mined, secondary metabolites of each strain were analyzed, and the bacterial community with both growth rate and enzyme production ability was developed. Therefore, a microbial degradation method with mild reaction conditions and rapid liquefaction of animal residues was developed. The liquid degradation of four common farm-raised animal residues (sheep, cattle, chickens, and pigs) was tested under laboratory conditions. The results showed that the liquid degradation of animal residues was achieved within 144 h, transforming the months-long anaerobic process of traditional compost fermentation process into a mere 6 days' anaerobic process. N, P, K plant nutrients accounted for 15% of the total matrix, pH value was 5.5–6.7, heavy metal content was less than 0.2 mg L−1. Designed and improved fermentation equipment, produced a 3 m³ fermentation equipment, used in chicken, pig two types of animal residues pilot test. The emissions of greenhouse gases such as CO2 in the entire degradation process were 1.6 × 104 ppm, which was 481 times less than that of composting by 7.7 × 106. This study provides a solution for the treatment of dead livestock and poultry, which has promotional and practical value.