Potential of Euphorbia caducifolia Haines as a Renewable Source for Biofuel

The shortage in the availability of fossil fuels leading to adverse effects on atmosphere has led to search for alternate crops as a source of biofuels. Euphorbia caducifolia Haines (family Euphorbiaceae), a latex yielding plant, grows abundantly in arid and semiarid regions. The phylloclades of this species are tough, succulent and fleshy, covered with divaricated sharp spiny stipules. The sticky milky latex flows out in abundance when any slight injury is caused to the plant. For the first time study was undertaken to extract biocrude from phylloclade dried biomass. This was to study its elemental analysis, gross calorific value and chemical analysis of biocrude for use as a possible biofuel crop. It was observed that the percentage of moisture content was lower in phylloclades collected from Nandimandalam (84.2 ± 3.7%) followed by Panyam (85.8 ± 0.7), Goothi (88.0 ± 0.7) and Gurramkonda (90.1 ± 0.5). Correspondingly the higher dry matter (15.8 ± 0.7%) was obtained from the phylloclades of Nandimandalam region when compared to the forest areas of other districts of Rayalaseema region. The ash content of dried biomass was reported to be 4.9 ± 1.0% for Nandimandalam followed by 5.3 ± 1.9% for Panyam, 5.7 ± 3.1% for Goothi and 6.2 ± 2.1% for Gurramkonda. Cyclohexane (CHE) biocrude obtained from dried biomass of Nandimandalam region (15.1 ± 0.4%) was higher followed by Goothi (14.4 ± 0.6%), Panyam (14.1 ± 1.3%) and Gurramkonda (14.1 ± 0.3%). The hexane biocrude (HE) also reported to be higher from the phylloclades collected from Nandimandalam (14.2 ± 0.4%) as compared to Goothi (13.6 ± 0.6%), Panyam (13.5 ± 0.6%) and Gurramkonda (13.0 ± 0.5%). Cyclohexane biocrude contained 81.1% carbon, 10.9% hydrogen and 0.2% nitrogen, while hexane biocrude contained 75.4% carbon, 10.7% hydrogen and 0.1% nitrogen. Gross calorific values for cyclohexane and hexane biocrude was 9, 465.9 cal/g and 8516.8 cal/g respectively and were almost comparable to crude oil (10, 505 cal/g). GC analysis indicating the presence of long aliphatic carbons. In proton NMR, the presence of peaks at the range of 0.7 to 1.2 ppm, 1.1 to 2.0 ppm and 4.6 to 5.2 ppm representing -CH3 group, -CH2 group and -CH group respectively, corresponded to the presence of poly isoprenoid structures. FTIR spectral analyses showed a broad peak at 3449.04 cm^-1 indicated the presence of -OH group, peaks at 2918 cm^-1 and 2849 cm-1 indicating the presence of amide and methylene groups. A peak at 1463 cm^-1, 1377 cm^-1, and 1239 cm^-1 indicated the presence of C = C, -CH3 and ether linkage (C-O-C). 804 cm^-1 and 828 cm^-1 peaks correspond to double bonded CH and tri substituted CH bending's respectively indicating the presence of isoprene and polyprene units. From these observations, this species may be considered as a potential and possible source of biofuel and chemical feed stocks.