Ana Gabriela Carvalho Rodrigues Do Nascimento

Equine farming generates a significant amount of waste, prompting the need for effective management. Composting enhanced by filamentous fungi holds promise for this purpose. This study focused on inoculating Aspergillus fumigatus isolates in composting horse bedding made with wood shavings (Pinus elliottii) The experiment lasted 90 days, with two treatment groups, control and inoculated, analyzing temperature, pH, electrical conductivity, total organic carbon and nitrogen content, cellulose, hemicellulose and lignina contents. Both treatments entered the thermophilic phase by the fourth day, reaching temperatures above 55 ºC and mesophilic maturation at 35 days (41 ± 0.2 ºC). The inoculated treatment exhibited higher electrical conductivity after 30 days and a more pronounced reduction in the total carbon content (42.85% vs. 38.29%) compared to the control. While there was no significant nitrogen difference, the inoculated treatment had a sharper reduction in C/N ratio, cellulose and hemicellulose content. Both treatments showed low coliform counts, no Salmonella sp. and reduced Strongyloides sp. larvae. Inoculating A. fumigatus in saturated horse bedding made from wood shavings improved compost quality, providing a possibility for sustainable equine farming waste treatment.

The treatment of saturated horse beds before they arrive at their final destination is necessary to avoid the risk of animal and environmental contamination. For this purpose, the composting process has great functionality due its to low cost, effectiveness, and operational ease. However, because of the nature of the materials used, this process can be long, and it is necessary to improve it to optimize composting cycles. This work aimed to isolate and identify fungi present in the compost piles of saturated equine bedding made with shavings and rice straw, identifying those with the greatest potential for cellulase production. Using specific cellulolytic media containing shavings or rice straw, seven strains were isolated. The total cellulase enzymatic activity of the isolates from the beds made with shavings was lower than that obtained from rice straw beds. Four strains showed high enzymatic potential for use in the shavings substrate (MA -6 2 f1, MA -6 2 f2, MA -7 9, and MA -7 10) and three for the rice straw substrate (PA -7 5, PA -7 7, and PA -7 10). The isolate PA -7 5 reached 0.376 IU mL⁻¹, the best index among all the isolates. These isolates were identified as belonging to the Aspergillus fumigatus species.