Bio-detoxification of Phorbol Esters and Other Anti-nutrients of Jatropha curcas Seed Cake by Fungal Cultures Using Solid-State Fermentation.

Jatropha seed cake, a byproduct after biodiesel extraction, has several anti-nutrients
and toxins. Solid-state fermentation was carried out for the detoxification of the Jatropha seed
cake (JSC) using different fungal cultures. The reduction in the anti-nutritional components
such as tannins, phytates, saponins, lectin and protease inhibitor, and phorbol esters on 6th,
9th, and 12th day of fermentation was analyzed. The phorbol ester content in the unfermented
JSC was 0.83 mg/g, and the maximum degradation of phorbol esters to the extent of 75 % was
observed in the case of JSC fermented with Cunninghamella echinulata CJS-90. The phytate
degradation in the fermented JSC was in the range of 65–96 %. There was a gradual reduction
of saponin content in the JSC from 6th to 12th day, and the reduction of saponin was in the
range of 55–99 % after solid-state fermentation. The trypsin inhibitor activity and lectin were
1,680 trypsin inhibitor units (TIU) per gram and 0.32 hemagglutinating unit in the unfermented JSC,
respectively. Trypsin inhibitor activity and lectin could not be detected in JSC after 12th day of solidstate
fermentation. Tannins accounted for 0.53 % in unfermented JSC, and there was a marginal
increase of tannins after solid-state fermentation. The results indicate that biological detoxification
could be a promising method to reduce anti-nutritional compounds and toxins in the JSC.