Advancing livestock waste fermentation via strategic organic substrate selection

Abstract

Increasing volumes of livestock waste have created a growing demand for efficient biotechnological methods for its management. Properly processed animal waste can not only reduce organic matter accumulation but also serve as an effective substitute for mineral fertilizers, thereby improving soil fertility. This study aimed to investigate the use of various organic substrates in the fermentation of animal waste for the production of biohumus. Thermophilic microorganisms capable of growth at 50℃ were isolated from cattle manure samples. All isolates were identified as members of the genus Bacillus. Enzymatic activities were evaluated using qualitative assays for cellulase, protease, amylase, and urease, along with biochemical tests for catalase and oxidase. The range of proteolytic index values produced by isolates with protease potential varied from 0.12 to 1.5. Amylase enzyme was detected in isolates I, II, and IV, with the highest activity observed in isolate IV (AI = 1.1). Among them, isolates I and II showed strong enzymatic activity across all investigated substrates, forming distinct hydrolysis zones that indicated efficient degradation of complex organic matter. The most active strains, characterized by high viable cell concentrations, are recommended for incorporation into biopreparations designed to accelerate organic waste fermentation and improve biohumus quality.