INFLUENCE OF PROVENANCE ON PLANT GROWTH, YIELD AND QUALITY OF BIODIESEL FROM SEEDS OF JATROPHA CURCAS L.

Abstract

Fast depleting non – renewable natural resources and increasing energy demand have stimulated interest in developing alternative fuel sources. Consequently, there is the need to research into bio – energy sources that are renewable and sustainable. Therefore, the influence of provenance on Jatropha curcas L. growth, biodiesel yield and quality of seed was assessed to promote biodiesel production from the plant in Nigeria. The seeds of the plant were collected from three provenances: Ibadan (Rainforest), New Bussa (Guinea savanna), and Kano (Sudan savanna)). One hundred and eighty (180) seeds were replicated on an experimental plot of 18 m x 40 m with espacement of 2 m x 2 m between and within alternate rows of three replicates by direct sowing. Thereafter, the data on morphology and physiology of Jatropha curcas were collected. The design of the experiment was Completely Randomized Design. Matured fruits were harvested six months after planting, weighed and dehulled manually. The oil was extracted from the seeds using n-hexane (40 - 60 °C). The physicochemical properties of the oil were determined in accordance with the standard methods of Association of Analytical Chemists, (AOAC). Biodiesel as well as glycerol produced through trans-esterification was measured. Thereafter, the physicochemical properties of the biodiesel were assessedbased on Tint and Mya method. Data collected were subjected to analysis of variance (ANOVA) at α 0.05 and Duncan Multiple Range Test. Seed sources differed significantly (P ≤ 0.05) in morphological parameters. Seedlings from Ibadan seed source had the best mean stem circumference (7.67, 16.31 and 23.34 mm) for 4, 8 and12 weeks after planting (WAP), than the other seed sources. New Bussa and Kano had the same stem circumference at 4WAP but different stem circumference at 12WAP. Also seedlings from Ibadan provenance had the best mean plant heights (0.16 m, 0.35 m and 0.57 m) for 4 WAP, 8 WAP and 12 WAP. Furthermore, seedlings from Ibadan seed source had the highest mean number of leaves (11.00, 37.65 and 42.15) for 4 WAP, 8 WAP and 12 WAP. Similarly, the seed sources differed significantly (P ≤ 0.05) in biomass. The average root biomass from Ibadan provenance had the biggest average root biomass values of 401.07 g and 803.79 g for 2 WAP and 12 WAP respectively. Besides, the highest stem biomass was obtained from Ibadan provenance (368.42g and 1028.23g) for 2 WAP and 12 WAP respectively. Likewise, Ibadan had greatest mean leaf biomass of 785.48 g and 977.01 g for 2 WAP and 12 WAP than other provenances. Furthermore, Ibadan provenance mean Crop Growth Rates of 501.93 gm2 day-1 was higher than the mean CGRs of the other provenances. Kano seed source had the best mean oil yield (59.77%) than other seed sources. However, the differences in oil yields among the three harvest periods were not significant (P ≥ 0.05). Provenance from Kano had the best biodiesel weight and highest yield (15.37 and 76.94%). Likewise, provenance from Kano had the highest glycerol weight and yield (1.92 and 9.59 % g). In addition, the lower the values of physicochemical properties the more the quality of the oil and biodiesel. There were significant differences in the Iodine values of the three provenances with Ibadan provenance having the lowest quality Iodine value (140.34 gI2 / 100g) than New Bussa and Kano provenances with Iodine value of 138.32 and 125.67 gI2 / 100g respectively. The mean density of J. curcas oil were 0.92, 0.92 and 0.90 for Ibadan, New Bussa and Kano seed sources respectively. Ibadan provenance had the lowest quality mean specific gravity and saponification values (0.89, 279.00 mgNaOH/g). Also, Ibadan provenance had the least quality peroxide value (0.51mgeq/kg). Provenance from New Bussa had the least quality free fatty acid (35.63 %). The differences in physicochemical properties of Jatropha curcas oil among the first, second and third harvests were not significant (P ≥ 0.05). Moreover, provenance from Ibadan had the lowest quality mean flash point (132.33oC) although the mean viscosity and density values from Ibadan were higher (4.44mm2/s and 834.89g/cm3). The mean biodiesel pour points were 9.63oC, 9.66oC and 9.63oC for first, second and third harvests respectively. There were significant differences in the means pour point of the three provenances. New Bussa had the lowest quality pour point (9.98oC). Also, Kano had the highest quality mean smoke point (107.50oC). Moreover, the second harvest had the best mean flash point, mean viscosity and average density (132.45oC, 4.35 mm2/s and 834.45 g/cm3).