Effect of oxygen concentration in the reproduction factor of S. carpocapsae cultured in an airlift reactor

In this paper is presented a study of the effect of oxygen concentration in the reproduction factor of S. carpocapsae cultured in an airlift reactor with external recirculation. The study involved the characterization of the airlift reactor in relation to mixing time and oxygen transfer coefficient for different air flows (0.2-1.5 L/min), and the monoxenic cultivation of S. carpocapsae carried out under controlled conditions of oxygen (0, 5%, 10% and 20%). The air flow of 0.5 L/min allowed a low mixing time and a fluid velocity near to the sedimentation speed of the female nematodes. It was noted that there was a minimum concentration of dissolved oxygen (5%) that favored the cultivation of S. carpocapsae in relation to the reproduction factor of IJs and the time for their production. With regard to control, the reproduction factor of IJs was increased by 21%, from 281 to 340, and the duration of the IJ production was reduced from 14 to 6 days. It is important to note that the minimum concentration of oxygen impacted the differential count of nematodes, from the 4 varied oxygen concentrations tested. The IJ cultivation carried out at a minimal oxygen concentration of 5% proved to be surprisingly synchronous and fast, with a transformation time per stage of 24 hours. These results could be considered of great value to producers of nematodes, considering that a new method was developed that allowed increasing nematode production, as well as reducing the operation cost.