P75: Enhanced Human Lysozyme Production by Kluyveromyces lactis K7 in Biofilm Reactor with Plastic Composite Support

Lysozyme is a lytic enzyme, which has antimicrobial, anti-inflammatory, and anti-viral effects. It has been used in food and pharmaceutical industry. Nowadays, lysozyme is commercially produced from egg white. However, egg-white lysozyme has disadvantages such as the immunological problems when applied to humans allergic to eggs and egg-white lysozyme has lower activity in bacteriolysis than human lysozyme. Therefore, the production of human lysozyme is needed to meet the demand. In this study, Kluyveromyces lactis K7, which has been transformed by the insertion of human lysozyme gene, was used for the production of lysozyme. Biofilm reactor with plastic composite support (PCS) was used to achieve high cell populations with low nutrition requirements and long durability.  The goal of this study was to determine the optimum fermentation conditions for the human lysozyme production by K. lactis K7 in biofilm reactor with PCS. The optimum growth parameters and fermentation medium composition were determined based on three factors Box–Behnken design of surface response methodology.  As a result, the lysozyme production at 25°C without pH and aeration control was significantly higher than the lysozyme production at other evaluated growth parameters (p<0.05). Moreover, the optimum medium composition was found as 16.3% lactose, 1.2% casamino acid, 0.8 % yeast nitrogen base. Overall, higher human lysozyme production amount and production rate in biofilm reactor (173 U/ml and 4 U/ml/h) were achieved when compared to the production in suspended cell reactor (110 U/ml and 2 U/ml/h).