Research Article COMPARATIVE CHARACTERIZATION OF LACTIC ACID BACTERIA ISOLATED FROM BOVINE AND NON-BOVINE MILK: FUNCTIONAL, ANTIMICROBIAL AND COSMETIC PERSPECTIVES

Abstract

Lactic acid bacteria (LAB) are promising probiotic microorganisms with applications in food, health, and cosmetic industries. The objective of this laboratory-based experimental study was to isolate LAB from bovine and non-bovine milk and compare their functional, antimicrobial, and cosmetic potential. A total of 30 raw milk samples (camel, goat, cow, and buffalo) were collected from dairy farms in Mumbai and neighbouring areas. LAB isolates were evaluated for probiotic characteristics including tolerance to bile salt, phenol, acidic pH, and NaCl, along with aggregation ability, hydrophobicity, and antibiofilm activity. Safety assessment was performed using haemolysis assays, and antimicrobial activity was evaluated using resazurin-based minimum inhibitory concentration (MIC) assays against selected pathogens. Phenotypic identification was followed by molecular confirmation using 16S rRNA gene sequencing. Statistical analysis was performed using one-way ANOVA and results were expressed as mean ± standard deviation. The results demonstrated strong bile tolerance percentage by isolate GMI 1 (87.6±0.04 %), phenol tolerance by isolate GMI 1 (85.8±0.15 %), and NaCl tolerance by isolate CMI 3(88.71±0.06%). Furthermore, GMI 1 demonstrated best survival at pH 2 (80.18±0.22 %) and pH 3 (90.32±0.47 %). Strains BFI 2 (Buffalo milk), CMI  3 (Cow milk), and GMI 1 (Goat milk) exhibited the most promising probiotic properties including high hydrophobicity, auto-aggregation, and antibiofilm activity against pathogens such as Acinetobacter baumannii. All isolates were non-haemolytic and exhibited gamma haemolysis on blood agar plate. Molecular analysis identified the potential isolates as Lactiplantibacillus plantarum (BFI  2), Ligilactobacillus salivarius (CMI 3) and Lactobacillus delbrueckii subsp. bulgaricus (GMI 1). These findings highlight the potential of selected LAB strains as promising candidates for probiotic-based therapeutic and cosmetic applications, particularly for skin health.