Natural amylase expression enhances starch utilization in Limosilactobacillus fermentum PJG11 from Dioscorea luzonensis

Lactic acid bacteria (LAB) are widely recognized for their health benefits and are commonly incorporated into functional foods. However, their survival and metabolic performance depend on the availability of appropriate substrates. This study evaluated the ability of LAB isolated from Dioscorea species to utilize starch from Dioscorea luzonensis, an endemic plant in the Philippines. Among the isolates tested, Limosilactobacillus fermentum PJG11 demonstrated the highest efficiency in converting D. luzonensis starch into glucose. This enhanced starch utilization can be explained by the upregulation of the α-amylase gene when the strain was cultured with its natural substrate, resulting in accelerated starch granule degradation. These findings underscore the importance of using natural, plant-derived substrates in the development of LAB-based functional foods to support optimal bacterial activity and improve carbohydrate breakdown for enhanced nutritional value.