Identification of best detoxification strategies for sustainable valorization of waste from Jatropha-based biodiesel industry: Compounding the benefits of plant-based vehicular fuel

• Published in: Environmental technology & innovation 2021-11, Vol.24, p.101911, Article 101911
• Main Authors: Phulia, Vikas, Sardar, Parimal, Jamwal, Ankur, Kumar, Vikas, N., Shamna, Fawole, Femi J., Sanap, Bhushan N., Sahu, N.P., Gupta, Subodh
• Format: Article
• Language: English
• Subjects: Chemical treatment; Irradiation; Jatropha kernel meal; Phorbol esters; Solid state fermentation
• ISSN: 2352-1864; 2352-1864
• DOI: 10.1016/j.eti.2021.101911

Bioenergy generated from plants is one of the best potential energy supplies. Recently, the non-edible Jatropha curcas has been considered one of the world’s most sustainable biofuel crops. Protein rich defatted Jatropha curcas kernel meal (DJKM) is toxic which contains phorbol esters (PEs, 1307 μg g−1) as a major toxic component, therefore it was detoxified through physical, chemical and solid-state fermentation treatments. Water soaking and moist heat treatment (autoclaving) had no significant effect on the PEs removal compared to control. Exposure of DJKM to electron beam radiation (2.5, 5, 10, 15 and 20 kGy) had a significant effect on PEs degradation and most efficient was at 25 kGy dose. Solvent extraction with either 90% methanol or 80% ethanol in combination with moist heat treatment was the most efficient method compared to other concentrations of methanol or ethanol. Solvent extraction of kernel meal through 0.2 or 0.3 M NaOH in 90% methanol and 0.1, 0.2 or 0.3 M NaOH in 80% ethanol, followed by moist heat treatment led to the removal of PEs completely. The PEs content in DJKM through highly alkaline methanol plus moist heat treatment (AM3.0) and ferric chloride & hydrogen peroxide plus moist heat treatments significantly (p< 0.05) decreased to 13.0 and 53.6 μg g−1, respectively. Non-alkaline solvent extraction of DJKM using either 90% methanol (M90H) or 80% ethanol (E80H) in addition to heating while magnetic stirring reduced PEs content significantly (p< 0.05) compared to control exhibiting 99.77 and 99.32% removal, respectively. The DJKM was free of PEs when it was treated via solid-state fermentation through Aspergillus niger fungus. Conclusively, chemical detoxification treatments are cumbersome, un-economical, and their incorporation in the diet may affect animal performance, whereas, the fermentation approach is cost economical, environmentally sustainable and offers greater efficiency. •Defatted Jatropha kernel meal is protein rich ingredient.•Toxic principle (phorbol esters) in the Jatropha meal needs to be eliminated.•Physical treatments did not degrade phorbol esters completely.•Solvent extraction using alkaline methanol or ethanol removed phorbol esters.•Solid-state fermentation completely detoxified Jatropha meal.