Effect of airflow rate on yields of Steinernema carpocapse Az 20 in liquidculture in an external-loop airlift bioreactor

Maximization of the contact between males and females is a key factor in th e production of the nematode Steinernema carpocapsae in a bioreactor. The influence of the airflow rate in male and female distribution and mass production in an external-loop bioreactor with a deceleration zone was stud ied. When operating at an airflow rate of 0.05 vvm, a high retention of fem ales in the deceleration zone of the bioreactor was observed and a larger n ematode productivity was obtained. At this aeration rate there was a higher proportion of males in that zone, which together with the lower circulatio n rate, increases the probability of encounters, thereby explaining the inc rease in productivity. (C) 2001 John Wiley & Sons, Inc.