Metabolic engineering of plant oils and waxes for use as industrial feedstocks

Abstract

SummarySociety has come to rely heavily on mineral oil for both energy and petrochemical needs. Plant lipids are uniquely suited to serve as a renewable source of high-value fatty acids for use as chemical feedstocks and as a substitute for current petrochemicals. Despite the broad variety of acyl structures encountered in nature and the cloning of many genes involved in their biosynthesis, attempts at engineering economic levels of specialty industrial fatty acids in major oilseed crops have so far met with only limited success. Much of the progress has been hampered by an incomplete knowledge of the fatty acid biosynthesis and accumulation pathways. This review covers new insights based on metabolic flux and reverse engineering studies that have changed our view of plant oil synthesis from a mostly linear process to instead an intricate network with acyl fluxes differing between plant species. These insights are leading to new strategies for high-level production of industrial fatty acids and waxes. Furthermore, progress in increasing the levels of oil and wax structures in storage and vegetative tissues has the potential to yield novel lipid production platforms. The challenge and opportunity for the next decade will be to marry these technologies when engineering current and new crops for the sustainable production of oil and wax feedstocks.

Fatty acid synthesis is inhibited by inefficient utilization of unusual fatty acids for glycerolipid assembly

“…S3 and Fig. S3 Discussion), as well as previous analysis of [ 14 2 O incorporation into lipids of CL37 compared with fae1 is consistent with a reduced rate of de novo FA synthesis in CL37. Thus, the reduced TAG accumulation in CL37 seeds is more likely due to less FA synthesis rather than increased FA β-oxidation.…”

“…Within the plant kingdom there are greater than 300 different types of "unusual FAs" that contain functional groups (e.g., hydroxy, epoxy, and cyclopropane) or have physical properties useful for replacing petroleum in the chemical industry (1,2). Unfortunately, most plants which naturally produce these unusual FAs have agronomic features which make them unsuitable as major crops.…”

“…Unfortunately, most plants which naturally produce these unusual FAs have agronomic features which make them unsuitable as major crops. Over the past 2 decades, most attempts to genetically engineer unusual FAs into oilseed crops or model species have produced only low proportions of the desired FA within TAG (2)(3)(4)(5). Additionally, in many cases, accumulation of unusual FAs in transgenic plants is accompanied by a reduction of total seed oil (6)(7)(8)(9)(10)(11); in some instances reductions of up to 50% of total seed oil have been reported (7,10).…”

Phospholipase Dζ Enhances Diacylglycerol Flux into Triacylglycerol

“…Therefore, there is considerable effort to increase the oil quality and yield in plants through breeding and application of biotechnology (Tan et al, 2011;Shi et al, 2012;Haslam et al, 2013;Vanhercke et al, 2013;van Erp et al, 2014;Li et al, 2015a). Though many of the involved genes have been cataloged and enzyme activities measured, a better understanding of the coordinated metabolic network ( Fig.…”

Identification of a Distinct, Cutin-Related Pathway for Biosynthesis of Triacylglycerol Lipids in Bayberry

“…Modern industrial uses of plant oils and waxes, particularly as replacementforfossilfuel-derived compounds, depend on the low cost and high-purity production of plant lipids (reviewed in Carlsson et al, 2011;Vanhercke et al, 2012). This identification of a novel pathway for TAG biosynthesis can inform strategies to improve plant lipids for industrial uses, by metabolic engineering or other approaches.…”