Metabolic Engineering of Higher Plants to Produce Bio-Industrial Oils

Abstract

Institute in Saskatoon. Research conducted by his team focuses on trying to understand how plants make oil, what determines the fatty acid composition of oil and how this can be changed for specific end uses. He uses Arabidopsis thaliana and the yeast Sacchromyces cerevisiae as model systems, but also works with oilseed Brassicas, and with Camelina sativa (false flax). Target fatty acids include hydroxy fatty acids such as ricinoleic acid, saturated fatty acids and very long chain fatty acids. Mark obtained his B.Sc and Ph.D. from the University of Bristol in England. He has worked in Canada since 1997. Plant Breeding and Acclimatization Institute in Poland. She has extensive experience in plant molecular biology, biochemistry and biotechnology. Over the last 12 years, she has been involved in project on genetic engineering of Brassica oilseed species to increase content of industrial and nutraceutic fatty acids. Her current research focuses on isolation and characterization of novel genes for increasing oil content in canola. AbstractVegetable oils have enormous potential as alternatives and replacements for mineral oil in a myriad of industrial applications. Although our knowledge of the genes and biochemical pathways leading to the formation of plant oils allows for the potential to engineer a diverse array of lipid products in seed oils, this goal remains a challenge. This review first summarizes current industrial uses of plant oils while highlighting features that make them attractive for industrial applications and presents a general overview of seed oil biosynthesis. Thereafter, the review considers various metabolic engineering strategies to achieve desired fatty acid compositions of seed oils for industrial applications. Among the target modifications examined are fatty acid chain length, level of desaturation and the presence of novel functional groups, which are introduced within the endoplasmic reticulum. The role of triacylglycerol assembly in accommodating industrially useful fatty acyl groups is also addressed. In addition, a section is devoted to examining the manipulation of key steps in carbon flow to increase seed oil content. The concept of producing oil in vegetative tissues is also addressed, as is the development of 'platforms' crops for the production of metabolically engineered bio-industrial oils. Finally, this review examines the potential of waxes for industrial applications which require lubricants that are more stable to hydrolysis at higher temperatures. 6 Key WordsBio-industrial oils, biodiesel, seed oil biosynthesis, membrane lipids, medium chain fatty acids, very long chain fatty acids, oil content, oleic acid, transcription factors, waxes, platform crops, Brassica carinata, Camelina sativa GlossaryCarbon Credit -A carbon credit is a generic term for any tradable certificate or permit representing the right to emit one tonne of carbon dioxide or carbon dioxide equivalent.Drying Oils -These oils are rich in polyunsaturated fatty acids and harden on exposure to air through oxida...

Comparative Transcriptomics Analysis of Brassica napus L. during Seed Maturation Reveals Dynamic Changes in Gene Expression between Embryos and Seed Coats and Distinct Expression Profiles of Acyl-CoA-Binding Proteins for Lipid Accumulation

“…Together oilseed rape accounts for around 16% of total vegetable oil production (Gunstone et�al. 2007, Taylor et�al. 2011).…”

A Review of Nervonic Acid Production in Plants: Prospects for the Genetic Engineering of High Nervonic Acid Cultivars Plants

“…However, C16 and C18 FA are typically found instead of NA in the sn-2 position in the fungus Mortierella capitata RD000969, microalga Mychonastes afer (Umemoto et al, 2014;Fan et al, 2018b). Similar limitation of further increase NA content also occurs in high-EA B. napus and B. carinata and negligible NA is found at the sn-2 position on the glycerol backbone because the ability of endogenous Brassica LPAAT to incorporate nervonoyl moieties into sn-2 position is very low (Scarth and Tang, 2006;Taylor et al, 2011). This bottleneck also limits the content of EA and other VLCFAs as the longer FAs tend to be localized at the sn-1,3 position, which restricts the level of NA, EA or other VLCFAs in the seed oil to a theoretical limit of 66%.…”

“…The third acylation reaction, converting DAG to TAG, is catalyzed by diacylglycerol acyltransferase (DGAT) enzymes at the sn-3 position using a fatty acyl-CoA (Figure 2) (Kennedy and Weiss, 1956). The research findings showed that NA can only be incorporated into the sn-1 or sn-3 position instead of sn-2 position of TAGs (Scarth and Tang, 2006;Taylor et al, 2011;Umemoto et al, 2014;Fan et al, 2018b).…”

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

“…This will involve increasing the oil productivity of existing oil crops, introducing additional oilseed crops and creating novel oil production platforms. Metabolic engineering has a central role to play in each of these pursuits and is already making significant contributions to addressing these goals, as has been well reviewed in recent years (Carlsson et al, 2011;Lu et al, 2011;Ohlrogge and Chapman, 2011;Taylor et al, 2011;Weselake et al, 2009). A wide array of metabolic engineering approaches have been employed to increase the oil content in a variety of plant tissues, including diverting carbon flow from starch to TAG, up-regulating fatty acid synthesis, modifying expression of individual TAG biosynthetic enzymes and transcription factors, and slowing the turnover of TAG.…”