<![CDATA[Chlorella vulgaris, a unicellular green microalga, is widely recognized for its rich nutritional profile and bioactive compounds that support microbial growth, making it a promising ingredient in functional food development. Supplementation in lactic acid bacteria (LAB) fermentation may enhance bacterial activity and improve product quality. This study aimed (1) to evaluate the nutritional composition of C. vulgaris and (2) to assess the effect of its supplementation in LAB growth substrates on the fermentation activity of two probiotic strains: Lactiplantibacillus plantarum 1 R 11.1.2 and L. plantarum 1 R 1.3.2. Four concentrations of C. vulgaris (0.25%, 0.5%, 0.75%, 1%) were applied, and proximate composition (moisture, ash, protein, fat, fiber, carbohydrate by difference) and fermentation parameters (pH value, total LAB count, total titratable acidity) were observed. Proximate analysis showed C. vulgaris contained 4.35% moisture, 6.72% ash, 30.01% protein, 1.24% fat, 15.10% fiber, and 42.58% carbohydrate (by difference), with a pH of 6.59. Fermentation results indicated that supplementation increased LAB growth (>9.49 log CFU/ml), accelerated pH reduction (4.67–4.34), and enhanced titratable acidity (>1.85%). L. plantarum 1 R 11.1.2 showed the strongest effect, with higher growth and acidification than L. plantarum 1 R 1.3.2. In conclusion, C. vulgaris supplementation, particularly at higher concentrations, significantly improved the fermentation performance of L. plantarum 1 R 11.1.2, supporting its potential use in functional and synbiotic food formulations.]]>
