Biofuel co-products as livestock feed - Opportunities and challenges

360Biofuel co-products as livestock feed – Opportunities and challengesFIGURE 3Distribution of phorbol esters in Jatropha curcas kernelConcentration of phorbol esters (g/kg) indifferent parts of Jatropha kernelsCross section of the kernelSource: Devappa, Makkar and Becker, 2011a.Kernel coat0.24Endosperm1.82Cotyledon0.053EpicotylHypocotyl0.01esters by 95 percent after four extractions. Heat treatmentin presence of alkali was also effective in reducing phorbolesters. Martinez-Herrera et al. (2006) studied the effect ofvarious treatments, such as hydrothermal processing techniques,solvent extraction, solvent extraction plus treatmentwith NaHCO 3 , and ionizing radiation, to inactivate the antinutritionalfactors in jatropha kernel meal. Trypsin inhibitorswere easily inactivated with moist heating at 121 °C for20 minutes (Makkar and Becker, 1997). Extraction withethanol, followed by treatment with 0.07 percent NaHCO 3considerably reduced lectin activity. The same treatmentalso decreased the phorbol ester content by 97.9 percent.Chivandi et al. (2004) reported that petroleum etherextraction reduced phorbol ester content in kernels ofJ. curcas seeds by 67.7 percent, and double solvent extractionfollowed by moist heat treatment reduced phorbolesters by 70.8 percent. Double solvent extraction accompaniedwith wet extrusion, re-extraction with hexane andmoist-heat treatment diminished phorbol ester content by87.7 percent. Rakshit and Bhagya (2007) reported that upto 90 percent of the phorbol esters could be removed bytreating the meal with 20 g/L of calcium hydroxide. Gaur(2009) developed a process that obtains high yields ofjatropha oil and detoxifies the defatted (oil-free) jatrophameal. The principle of solid-liquid extraction was utilized todetoxify the meal. Various organic solvents were used forthe extraction. Extraction of ground jatropha seed kernelsin a Soxhlet apparatus involving a sequential combinationof hexane, followed by methanol proved highly efficient indetoxifying the meal. Phorbol ester content was reduced by99.6 percent from 6.05 mg/g in untreated meal to about0.06 mg/g in solvent-treated meal.Chivandi et al. (2006) detoxified defatted J. curcaskernel meal (JCM) using 95 percent ethanol at 35 °C toremove most of the highly lipo-soluble phorbol esters inthe kernels. The ethanol-extracted meal was heated withpressurized steam at 90 °C for 30 minutes to distil offthe ethanol, after which the meal was sun-dried. The reextractedmeal was autoclaved at 121 °C for 30 minutesto inactivate the heat-labile antinutrients. This “detoxified”JCM was then fed to pigs for 8 weeks. Haematological andbiochemical parameters were measured and it was foundthat dietary ‘detoxified’ JCM caused severe adverse effectsin pigs. This demonstrates that the detoxification procedurehad failed to remove and/or neutralize the toxic factors inthe JCM. Some of the toxicity observed could be ascribedto the residual phorbol esters in the JCM. In the study ofBelewu, Belewu and Ogunsol (2010), autoclaved (121 °C,15 psi for 30 minutes) J. curcas seed cake was treated withfungi (Aspergillus niger and Trichoderma longibrachiatum)and fed to West African dwarf goats for 70 days. Phorbolester content was reported for neither the treated noruntreated J. curcas kernel cakes. The growth and nutrientutilization was lower in J. curcas cake-fed groups comparedwith the control, implying that the cake was not detoxifiedand could not be used as a component in animal feed.The solid-state fermentation (SSF) of seed cake usingthe white-rot fungi Bjerkandera adusta and Phlebia rufadecreased phorbol ester content by 91 and 97 percent,respectively, under optimized laboratory conditions (28 °Cfor 30 days) (de Barros et al., 2011). Similarly, SSF usingPseudomonas aeruginosa PseA strain decreased phorbolesters to an undetectable level within nine days underoptimized conditions (30 °C, pH 7.0 and relative humidity65 percent) (Joshi, Mathur and Khare, 2011). Animal studieshave not been conducted using material treated thus.In Hohenheim, Germany, a new method has been developedto detoxify jatropha kernel meal and protein isolate(Makkar and Becker, 2010a). This detoxification of kernelmeal and protein isolate is based on extraction of phorbolesters using organic solvents (alkaline methanol) and inactivationof trypsin inhibitors and lectin by heat treatment.Furthermore, these authors reported a one-step detoxificationmethod in which the proteins from mechanicallypressed jatropha seed cake were solubilized at pH 11, andthen the solubilized proteins were precipitated and detoxifiedusing ethanol at pH 8. These procedures are availablein patent (WIPO Patent, WO/2010/092143). The detoxified