Jannatul Ferdouse 1*, Shanta Paul 1, Mahzabin Muntaha Chowdhury 2,3, Ferdausi Ali 1 and Tanim Jabid Hossain 2,3*
1 Department of Microbiology, University of Chittagong, Chattogram 4331, Bangladesh
2 Department of Biochemistry and Molecular Biology, University of Chittagong, Chattogram 4331, Bangladesh
3 Laboratory for Health, Omics and Pathway Exploration (HOPE Lab), Chattogram 4331, Bangladesh
*(e-mail: ferdouse@cu.ac.bd (J.F.); tanim.bmb@gmail.com (T.J.H.);
Mobile: +880-1316790201 (J.F.); +880-1812092020 (T.J.H.))
ABSTRACT
To meet essential probiotic criteria—providing health benefits to the host, surviving gastrointestinal conditions, and ensuring safety for consumption—lactic acid bacteria (LAB) from food sources hold significant promise due to their natural origin and functional versatility. This study investigates Streptococcus thermophilus strain M2, a LAB isolated from the yogurt-based beverage Mattha, for its probiotic potential, functional competence, technological properties, and safety attributes. The strain exhibited broad-spectrum antimicrobial activity against both Gram-positive and Gram-negative bacterial pathogens, including Bacillus cereus, Staphylococcus aureus, Salmonella typhi, and Vibrio cholerae. It also demonstrated significant antioxidant activity, with a 71.51 ± 1.03% DPPH free radical scavenging capacity. Probiotic competence was evident through its tolerance to harsh gastrointestinal conditions, including low pH, bile salts, and phenol, suggesting its potential to survive and function in the gut. Furthermore, the strain displayed high cell surface hydrophobicity, auto-aggregation, and co-aggregation capabilities, which are critical for gut colonization and pathogen inhibition. Safety assessments confirmed its non-hemolytic nature and antibiotic susceptibility profile, with resistance to certain antibiotics. In addition, the strain exhibited desirable technological traits, including efficient milk coagulation and exopolysaccharide production, which are beneficial for enhancing dairy product quality. These findings collectively position S. thermophilus M2 as a versatile probiotic candidate with potential applications in gut health promotion and dairy product development. By utilizing a strain isolated from the traditional fermented beverage mattha, this research highlights the value of exploring underutilized, culturally significant foods as reservoirs for beneficial microorganisms.
Key words : probiotic lactic acid bacteria, Streptococcus thermophiles, probiotics health benefits, probiotic compatibility, antioxidant activity, fermented beverage