OBJECTIVES: To enhance hyaluronic acid (HA) production in Escherichia coli by utilizing hasA genes from Streptococcus pyogenes and Streptococcus parauberis, and employing metabolic engineering strategies. RESULTS: The expression of the hasA (SpaHasA) gene from S. parauberis in E. coli K12 W3110 led to higher HA production compared to the other gene. Knockout of the zwf and pfkA genes in the engineered E. coli expressing SpaHasA gene, further increased HA production to 891 mg l CONCLUSIONS: The hasA genes from various Streptococcus groups, especially S. parauberis, significantly boost HA production in E. coli, demonstrating their potential for microbial fermentation applications.