Liquid culture of the entomopathogenic nematod-bacterium-complex Heterorhabditis megidis Photorhabdus luminescens

A process technology for production of the entomopathogenic biocontrol nema tode-bacterium complex Heterorhabditis megidis/Photorhabdus luminescens in monoxenic liquid culture in laboratory scale bioreactors is described. Daue r juvenile yields varied between 21 and 68 million dauer juveniles/l medium . The maximum density was reached at 13 to 25 days after inoculation of Tt luminescens. The reason for the high variability in yield was identified. A fter the 23-h bacterial preculture the bioreactor is inoculated with nemato de dauer juveniles which develop to self-fertilizing hermaphrodites. The ex it from enduring dauer stages (recovery) was between 18 and 90% of the inoc ulum density. Low dauer juvenile recovery resulted in the development of tw o-generations within 20 to 25 days. In contrast, high dauer juvenile recove ry led to a one-generation process terminated within 15 days. Factors influ encing dauer recovery are still unknown.