Hyaluronic acid (HA) is a linear biopolymer naturally found in animal cells that functions as a lubricant, shock absorber, stabilizer of joint structure, and plays an important role in many biological signalling processes. However, the molecular weight of HA directly influences its physiochemical properties and determines its suitability for specific applications. As such, precise control over HA molecular weight during production or postproduction is essential to meet specific functional requirements. While chemical and physical methods to cut down HA are cheap, they allow low control of the molecular weight, can lead to environmental issues, and may be time consuming. Therefore, enzymatic treatment may be an effective alternative method to cut down HA to specific molecular weights. A promising and sustainable solution lies in the use of marine bacteria, which have the potential to produce novel enzymes that can depolymerize HA into defined lower molecular weight fragments. Due to the environment where they live in, marine microorganisms produce putatively more robust enzymes than terrestrial counterparts and may be more suitable for industrial applications.
This study aimed to identify marine bacterial strains capable of producing enzymes that selectively depolymerize HA into defined molecular weight fragments. Following the isolation of several marine bacteria, screening demonstrated that several species produced enzymes that were able to cut down high molecular weight HA. Notably, a Bacillus salacetis strain showed complete depolymerization efficiency. This strain was further evaluated in a membrane bioreactor system, where the cells were physically separated from the reaction medium. Even under these conditions, the strain achieved 100% conversion of high molecular weight HA into lower molecular weight fragments.