Microorganisms for degrading simmondsin and related cyanogenic toxins in jojoba

Abstract

Four microorganisms that metabolize simmondsin (S) and related cyanogenic toxins from jojoba (Simmondsia chinensis) were isolated by enrichment: Pseudallescheria boydii, a fungus which specifically degrades simmondsin ferulate but not S; Fusarium moniliforme; “Flavobacterium aurantiacum”; and Pseudomonas maltophilia. The latter three organisms grow on S as a sole carbon and nitrogen source in culture media, but only F. moniliforme attacks S in the complete jojoba meal. Combinations of the four microorganisms at two temperatures, and with free air or limited air exchange for up to 20 days, were tested on jojoba meal to determine an optimum detoxification method. Degradation of toxins was most rapid and complete when Pseudallescheria boydii and Fusarium moniliforme together were incubated on jojoba meal at 25°C with free air exchange for 20 days. Mice were fed fermented meals at 0, 5, 10 and 20% substitution levels to determine detoxification and nutritional quality. Average daily gains during rapid growth of weanling (1–3 weeks) and mature (4–8 weeks) mice did not differ significantly from controls for mice on all diets containing fermented meal. Diets containing fungally detoxified jojoba meal were more efficient for maintaenance of mature weight than jojoba meal detoxified with enzymes naturally present in the meal. Meal can be detoxified by ensilage for 20 days at 80% water content. Detoxification is attributed to as yet unidentified enzymes inherent in the jojoba seed.