Characterization and identification of lactic acid bacteria isolated from Napier grass and sugarcane top silages and their application for silage preparation

In this study, we aimed to isolate and characterize lactic acid bacteria (LAB) from mixed Napier grass (NG) and sugarcane top (ST) silages, and to evaluate their effects on silage quality as alternative LAB inoculants. Among the 370 LAB strains isolated from silage and screened for tolerance to pH 3.7, we identified 17 strains with distinct colony shapes and sources. Strains XH146 and XH352 exhibited the strongest ability to produce acid in Man Rogosa Sharpe broth and were identified as Lactiplantibacillus paracasei and Lactiplantibacillus plantarum, respectively. Strains XH146 (LAB1), XH352 (LAB2), and L. plantarum Chikuso-1 (FG, a commercial inoculant) were used as additives for NG and ST silage preparation. All inoculated silages were better preserved than the control. LAB addition significantly reduced the pH of NG silage, with the lowest pH and the highest lactic acid content found in the combined LAB1 + LAB2 treatment. NH3-N contents decreased in the following order: Control > LAB1 > LAB2 > FG > LAB1 + LAB2. In conclusion, L. paracasei XH146 and L. plantarum XH352 demonstrated the highest ability to enhance silage quality, making them promising candidates for silage inoculants.