A comprehensive review on microbial hyaluronan-degrading enzymes: from virulence factors to biotechnological tools.

Hyaluronan (HA), a natural high molecular weight polysaccharide, has extensive applications in cosmetology and medical treatment. Hyaluronan-degrading enzymes (Hyals) act as molecular scissors that cleave HA by breaking the glucosidic linkage. Hyals are present in diverse organisms, including vertebrates, invertebrates and microorganisms, and play momentous roles in biological processes. In recent years, microbial Hyals (mHyals) have gained considerable attention for their exceptional performance in the production and processing of HA. Moreover, the applications of mHyals have been greatly extended to various biomedical fields. To explore the potential applications of mHyals, a thorough comprehension is imperative. In this context, this review systematically summarizes the sources, structures, mechanisms and enzymatic properties of mHyals and discusses their biological functions in host invasion, disease development, and regulation of intestinal flora. Furthermore, versatile applications inspired by their biological functions in medicine development, molecular biology, and industrial biotechnology are comprehensively reviewed. Finally, prospects are presented to emphasize the importance of exploration, expression and characterization of mHyals and the necessity of excavating their potential in biotechnological fields.