Dedicated Industrial Oilseed Crops as Metabolic Engineering Platforms for Sustainable Industrial Feedstock Production

Abstract

Feedstocks for industrial applications ranging from polymers to lubricants are largely derived from petroleum, a non-renewable resource. Vegetable oils with fatty acid structures and storage forms tailored for specific industrial uses offer renewable and potentially sustainable sources of petrochemical-type functionalities. A wide array of industrial vegetable oils can be generated through biotechnology, but will likely require non-commodity oilseed platforms dedicated to specialty oil production for commercial acceptance. Here we show the feasibility of three Brassicaceae oilseeds crambe, camelina, and carinata, none of which are widely cultivated for food use, as hosts for complex metabolic engineering of wax esters for lubricant applications. Lines producing wax esters >20% of total seed oil were generated for each crop and further improved for high temperature oxidative stability by down-regulation of fatty acid polyunsaturation. Field cultivation of optimized wax ester-producing crambe demonstrated commercial utility of these engineered crops and a path for sustainable production of other industrial oils in dedicated specialty oilseeds.

Camelina, a Swiss knife for plant lipid biotechnology

“…Since wax ester synthesis uses acyl-CoA as substrates, and thus competes directly with TAG synthesis, a possible improvement would be to favor substrate channelling toward wax ester biosynthesis instead of TAG. Recently, a relative 30% content in wax ester was achieved in camelina by the combined overexpression of jojoba FAR and WS with L. annua FAE1 and associated with FAD2 inhibition (Zhu et al, 2016). Nevertheless, camelina yields were lower than those of Crambe abyssinica transformed with the same constructs, perhaps because that the latter naturally accumulates high levels of very long chain fatty acids (Zhu et al, 2016).…”

Quantification and Discovery of Acyl-ACPs by LC-MS/MS

“…The synthesis of fatty acyl chains is essential for the production of storage and membrane lipids and functional molecules that modulate gene expression or contribute to protein activity. Studies on acyl chains span from disease and nutrition to demands for renewable fuels and feedstocks (Uauy et al, 2000; Peralta-Yahya et al, 2012; Zhu et al, 2016; Vanhercke et al, 2019). The lengths of up to 18 carbons are produced during fatty acid biosynthesis (Li-Beisson et al, 2013) on an acyl carrier protein scaffold (Overath and Stumpf, 1964) which is connected to the acyl chain through linkage of a 4’-phosphopantetheine group to a serine residue of the protein (ACP; Fig.…”

Natural trait variation for taxonomic classification and breeding potential assessment in the genus Camelina

“…Incentives to introduce novel crop plants for non-food applications are due to the recent progress in the establishment of a bio-based economy (Zhu et al, 2016). The high energy density of the fatty acid components of vegetable oils have been increasingly used in recent years for the production of biofuels and various industrial materials as renewable resources (Zhu et al, 2016).…”

“…Camelina can fulfill this criterion given the fact that its oil has not been established as a major component of the human diet whereas domesticated oilseed crops such as soybean and rapeseed already serve this purpose. Developing food crops for industrial applications complicates matters and there are growing public and regulatory concerns associated with mixing of seeds for edible and industrial markets (Zhu et al, 2016). Furthermore, studies have shown that the life cycle analysis for corn-based ethanol as a biofuel substitute for gasoline actually increases greenhouse gas emissions over time which questions the sustainability of this process (Searchinger et al, 2008).…”

“…Instead, camelina development could be geared towards niche markets involving highvalue bio-based products as renewable substitutes to the variety of industrial materials currently derived from petroleum (Bansal & Durrett, 2016;Zhu et al, 2016). Development for polymers, varnishes, paints, cosmetics, and dermatological products are of particular relevance as the high levels of unsaturated fatty acids in the oil is associated with its fast-drying characteristics (Kasetaite et al, 2014).…”