Developing Brassica carinata as a biodiesel crop
Submitted 30 August 2026
ABSTRACT
The transition from fossil-derived liquid fuels to renewable transportation
energy sources is essential for mitigating environmental degradation and enhancing
public health outcomes. In this context, plant-derived oils have emerged as promising
feedstocks for sustainable biofuel production. Advances in crop bioengineering
approaches offer powerful tools to modify the yields and physicochemical properties of
plant oils, enabling the development of feedstocks tailored for next-generation biofuels.
Among oil producing plants, Brassica carinata (A. Braun), which is a non-edible
oilseed species, is a potential biofuel feedstock due to its resilience, adaptability to
diverse agroecological environments, and suitability for cultivation on marginal lands
that do not compete with food production systems. Beyond these advantages, further
research is required to improve B. carinata oil quality and to assess the species’ genetic
diversity for industrial applications. This study investigated the optimization of B.
carinata oil properties through two complementary approaches.
The first approach focused on assessing natural variation in B. carinata oil
content and composition across a diverse germplasm set, including a panel of accessions
and a doubled haploid (DH) population derived from Yellowcross and Whiteban
parental lines. B. carinata accessions were evaluated under both field and birdcage
conditions across two years in Wagga Wagga, Australia, in collaboration with the New
South Wales Department of Primary Industries and Regional Development. Mature
seeds were harvested and analysed for total oil content and fatty acid composition.
Emphasis was placed on identifying lines with contrasting erucic acid levels, which
were subsequently selected for detailed characterisation and potential use in breeding
programs. Statistical analysis revealed 1.5-fold variation in seed oil content (25.7–
44.8% across germplasm and seasons) and variation in fatty acid composition, with
monounsaturated fatty acids (MUFAs) ranging from 48.1% to 66.0% and
polyunsaturated fatty acids (PUFAs) from 21.9% to 35.7% of total fatty acids,
highlighting significant opportunities for selection and genetic improvement.
The second approach involved the metabolic engineering of B. carinata to
modify fatty acid biosynthesis pathways. Specifically, gene constructs encoding
enzymes involved in fatty acid chain elongation were introduced to alter fatty acid chain
length and composition. To enable this, an efficient Agrobacterium-mediated
transformation protocol was developed and optimised for B. carinata, building upon
previously established methodologies (Bhalla & Singh, 2008; Li et al., 2010). The
optimised protocol facilitated reliable transformation and regeneration of transgenic
lines. Targeted genetic modification resulted in significant alterations to the fatty acid
profile of B. carinata oil, characterised by an increase in monounsaturated fatty acids
(principally erucic acid, C22:1) and a concomitant reduction in polyunsaturated fatty
acids. This compositional shift is advantageous for biofuel applications, as it enhances
oxidative stability while maintaining desirable fuel properties. Notably, the modified
lines exhibited an improved fatty acid profile compared with Brassica napus, a widely
utilised biodiesel feedstock. The enhanced oil composition would be expected to confer
favourable fuel characteristics, including increased oxidative stability, reduced viscosity
and cleaner combustion with lower emissions. These attributes are needed for meeting
international biodiesel standards and ensuring compatibility with existing fuel infrastructure.
Overall, this research addresses key knowledge gaps regarding the genetic
variability of oil traits in B. carinata and demonstrates the effectiveness of integrating
conventional selection with advanced genetic engineering to develop improved biofuel
feedstocks. The findings highlight the potential of B. carinata as a sustainable, high performance
oilseed crop for renewable energy production relevant to increasing global
energy demand, mitigating climate change and meeting the liquid fuel needs of a
growing population.