A new medium for liquid fermentation of Steinernema feltiae: selection of lipid and protein sources

Authors: LEITE, LUIS - Instituto Biologicio - Brazil; Shapiro Ilan, David; HAZIR, SELCUK - Adnan Mederes University; Jackson, Mark

Submitted to: Nematropica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/29/2016
Publication Date: 2/27/2017
Citation: Leite, L., Shapiro Ilan, D.I., Hazir, S., Jackson, M.A. 2017. A new medium for liquid fermentation of Steinernema feltiae: selection of lipid and protein sources. Nematropica. 46(2):147-153.

Interpretive Summary: Entomopathogenic nematodes, also known as beneficial nematodes, are small worms that can be used as environmentally-friendly bio-insecticides. One barrier to wider usage of these nematodes in insect pest management is the high costs associated with producing the nematodes. Therefore, we are studying methods to improve nematode production and reduce costs. Most nematodes are grown in liquid fermentation tanks. In this study, we investigated the effects of different protein or lipid sources to improve production. We also investigated the effects of adding small amounts of sugar (glucose). Lipid source (including canola oil, palm oil, peanut oil) did not affect nematode production but addition of pork lard was detrimental. For protein, the combination of egg yolk + egg white increased the nematode yield compared to the sources tested individually. Also, the addition of 2.5% glucose increased nematode yields. Additional research will be conducted to improve nematode nutrition and quality during liquid fermentation.

Technical Abstract: Despite great progress in the past couple of decades, entomopathogenic nematode production in liquid fermentation still requires improvements to maximize efficiency, yield and nematode quality. Thus, the objective of this study was to develop a more suitable liquid medium for mass production of S. feltiae by selecting optimum lipid and nitrogen sources, and by assessing the impact of glucose. In the first experiment, seven lipid sources (corn oil, palm oil, fish oil, peanut oil, sun oil, canola oil and pork lard) were tested at a concentration of 4% (v/v) in media containing yeast extract (2.3% w/v), NaCl (0.5% w/v), egg yolk (1.25% w/v) and agar (0.2% w/v). In the second experiment, S. feltiae was grown in media containing either corn or peanut oil (4% v/v), yeast extract (2.3% w/v), NaCl (0.5% w/v) and agar (0.2% w/v), with either egg yolk, yeast extract, egg white, soy extract, beef extract or fish collagen at a concentration of 1.25% (w/v). In the third experiment, 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 for each one) 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 sources experiments, pork lard and yeast extract differed significantly providing the lowest yields. The combination of egg yolk + egg white increases the nematode yield compared to these nitrogen sources tested individually. Also, the addition of 2.5% glucose increased nematode yields.