Growth and Hyaluronic acid production in Streptococcus equi species

Hyaluronic acid (HA) is a glycosaminoglycan which exists ubiquitously in organisms, where it possesses a range of important functions. Due to the rheological properties and biocompatibility of HA solutions, it has been employed as a device used in ophthalmic surgery for cushioning of the vitreous humour as well as a lubricant for the treatment of arthritic joints. More recently it has been the target of research in regenerative medicine and cancer treatment due to its tolerance for chemical modifications and cross linking. The rheology of a HA solution is a consequence of the concentration and molecular weight of the HA present. Consequently, the ability to produce high molecular weight HA is desirable in production for medical devices. The current commonly used method for HA production is bacterial fermentation. Group C Streptococcus species produce HA as a protective capsule to evade immune responses of their hosts. These are fastidious organisms and the fermentation process requires strict regulation of culture parameters in order to obtain optimum yields. A disadvantage of bacterial HA production is that the molecular weight of the product is often lower than the ideal range. The aim of this project is to investigate environmental and genetic factors influencing HA capsule production in a strain of Streptococcus equi currently used in industrial HA fermentation.