Identification of low-temperature-tolerant lactic acid bacteria in Helianthus tuberosus silage in alpine regions

This study aimed to identify low temperature-tolerant lactic acid bacteria (LAB) that can improve the fermentation quality of Helianthus tuberosus silage in alpine regions. The H. tuberosus silage named ‘Qingyu No.2’ was used as the material, and LAB was separated using the plate method. Physiological and biochemical characteristics were used to analyze the characteristics of the strains, and 16S rRNA sequencing was conducted to identify the strain species. The results showed that a total of 34 LAB were separated. Among them, 13 LAB, including 11 homotypic fermented LAB and two heterotypic fermented LAB, were identified with low temperature tolerance by physiological and biochemical screening. It was found that the strain GN02 grew faster (OD = 2.63). GN10 was found to have a stronger acid-producing capacity (pH = 3.59) by comparing the acid production and growth capacity at low temperatures, and LAB XN25 combined the two characteristics. Nine strains of Lactiplantibacillus plantarum, one strain of L. pentosus, one strain of L. coryniformis, one strain of L. brevis, and one strain that could not be identified were detected through 16S rRNA sequencing at species level. The study found the potential low-temperature-tolerant LAB, one strain of L. plantarum, one strain of L. pentosus, and one strain of L. brevis suitable for the fermentation of H. tuberosus silage in alpine regions.