Mass production of entomopathogenic nematode, Heterorhabditits megidis by using micorosparger of gandong strain

In this study, the effects of microsparger on oxygen transfer velocity caused by micro aeration and reproduction of Heterorhabditis megidis in the process of using microsparger for mass culture production of entomopathogenic nematodes, Heterorhabditis megidis were examined. When ringsparger and microsparger were used in the incubator, changes in oxygen transfer coefficients (K_La) were measured. It tended to significantly increase when microsparger with small pore size was used. It seemed to be caused by increase in the contact area between air bubbles and media. On the other hand, in the case of microsparger, the K_La value was not increased, but it tended to be decreased when pore size got smaller despite the increase in aeration rate and stirring rate. In addition, Oxygen Uptake Rate (OUR) of Heterorhabditis megidis was 0.63×10^-2mmol O₂/L-min at appropriate incubation temperature of around 25°C, and it tended to rapidly increase. While being cultured, the number of the optimal inoculated bacteria in 4,000 showed the highest yield of 300×10³. On the 9^th day of incubation, the final yield of 3 stage IJ per ml was 400×10³. 25μm micro-spargerwas attached to the incubator with capacity of 3 1 and Heterorhabditis megidis was cultured. As the result, Heterorhabditis megidisgrew with a high yield only when dissolved oxygen concentration fell below 20% and it was ventilated rather than continuous aeration.