Hyaluronic acid (HA) is a high value biopolymer extensively used in biomedical and cosmetic applications due to its biocompatibility, viscoelasticity, and strong water retention capacity. Microbial fermentation has emerged as a scalable and efficient alternative to animal derived HA. This study investigated the impact of microbial competition between Streptococcus zooepidemicus (Sz) and Streptococcus pyogenes (Sp) on HA production under different aeration regimes closed (anoxic), semi-closed (partially aerated); and controlled aerated bioreactor systems. Mono- and co-culture fermentations were conducted at varying inoculation ratios. The highest HA yield was obtained at a 1:1 inoculation ratio (Sz 5:Sp 5), producing 0.824 g/L in the closed system, 0.909 g/L in the semi-closed system, and 1.15 g/L in the bioreactor. Statistical analyses (Kruskal-Wallis and Dunn's tests) revealed that HA production in co-culture systems was significantly higher than in monocultures (p < 0.05), and that increasing aeration enhanced HA yields across all systems. These findings demonstrate that controlled aeration and balanced co-culture synergistically improve HA biosynthesis, highlighting a promising strategy for scalable and cost effective industrial production.
Öz et al. (Mon,) studied this question.