Effect Of Carbon Source on The Production of Hyaluronic Acid from Non-Pathogenic Streptococcus Thermophilus

Hyaluronic acid (HA) is a linear glycosaminoglycan composed of repeating disaccharide units of D-glucuronic acid and N-acetylglucosamine linked by β-1,3 and β-1,4 glycosidic bonds. Due to its excellent water-retention capacity, viscoelasticity, biocompatibility, and lack of immunogenicity, HA is widely used in cosmetic, biomedical, and food industries. Conventional HA production by extraction from rooster combs is costly, time-consuming, and associated with risks such as enzymatic degradation and inflammatory reactions. Although industrial fermentation using Streptococcus equi subsp. zooepidemicus yields high HA levels, its pathogenic nature raises safety concerns. Therefore, this study aimed to explore non-pathogenic alternatives for HA production. Streptococcus thermophilus strains were isolated from yogurt samples and evaluated for their ability to produce HA as part of exopolysaccharides. The isolates were cultivated in MRS broth and a hyaluronic acid production medium supplemented with lactose, glucose, and sucrose. Fermentation was carried out in 100 mL culture volumes at 37 °C for 24 hours at pH 6.8, using a 1% (v/v) inoculum and agitation at 80 rpm. After fermentation, HA was isolated and purified. The study highlights the potential of dairy-derived S. thermophilus as a safe microbial source for HA production.