The effect of genotype and environment on biodiesel quality prepared from Indian mustard (Brassica juncea) grown in Australia

Abstract

Two experiments were conducted in north-western New South Wales, Australia to determine the effect of genotype (G), growing site (S) and year (Y) on the suitability of Indian mustard (Brassica juncea) as a biodiesel feedstock. The first experiment analyzed the effect of growing environment on six mustard genotypes while the second experiment analyzed the effect of sowing on the same genotypes across two seasons. The results demonstrate that late sowing forced maturity of the seed and decreased the yield whilst early sowing resulted in economically viable seed yields (>1.3t/ha). The oil content of the seed ranged from 34 to 39.8% and the main fatty acids present in the oil were oleic (C18:1) and linoleic acid (C18:2) in both experiments. The main factor that impacted on the fatty acid profile in a single season was the seed genotype while in the second experiment the growing year and interactions between year and the other parameters had a major impact on the fatty acid profile. The main fatty acids affected by the growing year were oleic, linoleic and erucic (C22:1). Oleic and linoleic acids were inversely correlated with erucic acid content which tended to be higher in cooler growing conditions. Two of the genotypes were processed into biodiesel and assessed for quality and the fuel met most requirements except for oxidation stability and kinematic viscosity. The relatively high concentration of polyunsaturated fatty acids was deemed to be responsible for the poor oxidation stability and higher amounts of erucic acid and glycerol would contribute to poor kinematic viscosity values. The mustard genotypes analyzed may prove to be both a viable break crop as well as providing a good feedstock for the establishment of a biodiesel industry in this area.