Exopolysaccharides are a type of polysaccharide produced by various bacteria through cellular excretion. Lactic acid bacteria-produced exopolysaccharide has comparable physicochemical properties to certain plant polysaccharides such as guar gum or pectin. Hence, they provide functional roles in the food industry, such as replacement for gluten in baked goods, alternative thickeners, stabilizers, and even providing health benefits. Currently, exopolysaccharide-producing lactic acid bacteria strains have become highly sought after for research and commercial purposes. However, isolation and characterization from indigenous fruit sources remain insufficiently explored, despite the wide diversity of said fruits and their distinct microbial terroirs. Anna apples are indigenous apple cultivar from Malang, Indonesia, known to have a high sugar content, moderate acidity, as well as containing various vitamins and minerals, suitable for lactic acid bacteria growth. This study aims to isolate and identify endophytic lactic acid bacteria from Anna apple cultivar (Malus domestica var. Anna) mesocarp, as a potential exopolysaccharide producer. Isolation and purification produced eight isolates, respectively BAA-1 through BAA-8. The isolates were then characterized via Gram staining, endospore staining, catalase activity assay, carbohydrate fermentation assay, and exopolysaccharide production yield. Results indicate that isolates BAA-5 and BAA-8 produced the highest yields of exopolysaccharide, which were 3350 mg/L and 3050 mg/L respectively. Further molecular identification showed that isolate BAA-5 had a 98.68% gene sequence similarity to Lacticaseibacillus paracasei, while isolate BAA-8 had a 99.74% sequence similarity to Lactiplantibacillus plantarum. Thus, the two isolates can potentially be developed as functional agents in food industrial applications.
Kusmiyati et al. (Thu,) studied this question.