SUMMARY
Entomopathogenic nematode production in liquid fermentation still requires improvements to maximize efficiency, yield, and nematode quality. The objective of this study was to develop a more suitable liquid medium for mass production of S. feltiae by selecting lipid and nitrogen sources, and by assessing the impact of glucose. Seven sources of lipid (corn oil, palm oil, fish oil, peanut oil, sunflower oil, canola oil, and pork lard) and six of nitrogen (egg yolk, yeast extract, egg white, soy extract, beef extract, and fish collagen) were tested at a concentration of 4% (v/v) and 1.25% (w/v), respectively. Additionally, egg yolk and egg white selected in the previous experiment, were tested solely (both at 1.25% w/v) and combined (at 0.625% w/v each) in media with or without glucose (2.5% w/v), supplemented also with yeast extract (2.3% w/v), NaCl (0.5% w/v), peanut oil (4% v/v), and agar (0.2% w/v). For the lipid and nitrogen source experiments, pork lard and yeast extract provided the lowest yields. The combination of egg yolk + egg white increased nematode yield compared to these nitrogen sources tested individually. Also, the addition of 2.5% glucose increased nematode yields.