Potential of Bacteria Isolated from Fermented Rumen Content as Fungal Pathogen Antagonists, Phosphate Solubilizers, and Liquid Fertilizer for Rice Plants

This study aimed to evaluate the ability of microbes from the rumen contents of cattle as antagonists of pathogenic fungi and as liquid organic fertilizer (LOF) containing P-solubilizing bacteria in rice plants. The mixture consisting of 5 kg rumen contents of cattle, 2 kg of rice bran, 1 kg of molasses, and 10 L of tap water was fermented for 14 days. After fermentation, the mixture was filtered to separate the liquid from the solid components. The solid portion was collected for the isolation and screening of contained bacteria. Subsequent tests included biochemical tests, antagonistic activity tests, DNA extraction, PCR amplification, phosphate solubilization ability testing, inhibitory ability study, and application of LOF in a screen house. One bacterial isolate (PTK2TB code) exhibited the highest antagonistic activity against three tested pathogenic fungi (inhibits more than 50%). Subsequent 16SrDNA sequence analysis showed that this isolate belongs to the same group as the type strain and reference strain of Bacillus amyloliquefaciens. Furthermore, out of the 90 bacterial isolates obtained, 20 demonstrated a high capacity for phosphate solubilization. Additionally, LOF containing phosphate-solubilizing bacterial isolates positively impacted rice growth and yield.