This study focused on the solid-state fermentation of Jatropha seed cake (JSC), a byproduct generated after biodiesel production. Presence of anti-nutritional compounds and toxins restricts its application in livestock feed. The disposal of the JSC is a major environmental problem in the future, due to the generation of huge quantity of JSC after biodiesel extraction. Hence the JSC was assessed for its suitability as substrate for production and optimization of lipase and protease from Aspergillus versicolor CJS-98 by solid-state fermentation (SSF). The present study was also focused on the biodetoxification of anti-nutrients and toxins in JSC. The SSF parameters were optimized for maximum production of lipase and protease. Under the optimized conditions, the JSC supplemented with maltose and peptone (2%), adjusted to pH 7.0, moisture content 40%, inoculated with 1 x 10(7) spores per 5 g cake and incubated at 25 degrees C, produced maximum lipase, 1288 U/g and protease, 3366 U/g at 96 h. The anti-nutrients like phytic acid (6.08%), tannins (0.37%), trypsin inhibitors (697.5 TIU/g), cyanogenic glucosides (692.5 mu g/100 g), and lectins (0.309 mg/ml), were reduced to 1.70%, 0.23%, 12.5 TIU/g, 560.6 mu g/100 g and 0.034 mg/ml respectively. The main toxic compound phorbol esters content in the ISC was reduced from 0.083% to 0.015% after SSF. Our results indicate that viability of SSF to utilize the huge amount of seed cake generated after extraction of biodiesel, for production of industrial enzymes and biodetoxification of anti-nutrients, toxins. (C) 2013, The Society for Biotechnology, Japan. All rights reserved.