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Biotechnological Improvement of Soybean Oil for Lubricant Applications
Published in Leslie R. Rudnick, Synthetics, Mineral Oils, and Bio-Based Lubricants, 2020
Peng Wang, Xiangjun Li, Edgar B. Cahoon
The most significant functional constraint for the use of soybean oil in lubricants is its inherent lack of oxidative stability. This is largely the result of high levels of polyunsaturated fatty acids that are present in soybean oil. Polyunsaturated fatty acids in soybean oil include linoleic acid (18:2Δ9,12), which compromises 50%–55% of the oil, and linolenic acid (18:3Δ9,12,15), which comprises 10%–15% of the oil. The biochemical production of the Δ12 double bond of these fatty acids is catalyzed by a fatty acid desaturase referred to as FAD2, and the Δ15 double bond of linolenic acid is produced by a separate fatty acid desaturase referred to as FAD3. These enzymes remove hydrogen atoms from the C12, C13 atoms or C15, C16 atoms to generate double bonds. These reactions occur in the endoplasmic reticulum of the cells of soybean seeds, while the fatty acid substrates are transiently bound to the phospholipid phosphatidylcholine [16]. FAD2 and FAD3 are encoded by multiple genes in soybean [12,17]. FAD2-1A and FAD2-1B are the primary FAD2 genes that are expressed in soybean seeds and the major targets for engineering of reduced polyunsaturation of soybean oil [17].
Tailoring Triacylglycerol Biosynthetic Pathway in Plants for Biofuel Production
Published in Arindam Kuila, Sustainable Biofuel and Biomass, 2019
Kshitija Sinha, Ranjeet Kaur, Rupam Kumar Bhunia
Polyunsaturated fatty acids are formed from phosphatidylcholine by the actions of membrane-bound fatty acid desaturase 2 and 3 (FAD2 and FAD3) (Bhunia et al., 2016). These enzymes convert the oleoyl groups to linoleoyl and linolenoyl, respectively. In some plant species, the polyunsaturated fatty acids form by the action of desaturases but the substrate used here is acyl-CoA. The developing cotyledons of soybean have shown the presence of distinct pools of DAG in the ER. DAG produced by the action of PAP participates in phosphatidylcholine synthesis, whereas DAG used in TAG assembly by DGAT was derived from phosphatidylcholine. DAG and CDP-choline react together in the presence of an enzyme called diacylglycerol: cholinephosphotransferase (CPT) to form phosphatidylcholine. Also, an enzyme called phosphatidylcholine:diacylg lycerol cholinephosphotransferase (PDCT) has been found in Arabidopsis and is believed to participate in the transfer of phosphocholine from phosphatidylcholine to DAG. This, most probably, can reverse the actions by moving DAG-containing oleoyl moieties into phosphatidylcholine and removing DAG-containing polyunsaturated fatty acids (PUFA) from phosphatidylcholine, which would ultimately make DAG available for its conversion into TAG via the actions of DGAT (Weselake et al., AOCS lipid library).
Lowering the culture medium temperature improves the omega-3 fatty acid production in marine microalga Isochrysis sp. CASA CC 101
Published in Preparative Biochemistry & Biotechnology, 2021
Jeyakumar Balakrishnan, Kathiresan Shanmugam
Fatty acid desaturases (FADs) add a double bond to the growing fatty acid chain in omega-3 fatty acid metabolism. The mRNA expression of three desaturases Δ6Des, Δ5Des, and Δ4Des showed a significant difference in their pattern (Figure 3). Δ6Des is an important rate-limiting enzyme in the omega-3 pathway. There was no significant difference in the expression of Δ6Des between the two treatments. Furthermore, Δ5Des which add a double bond to eicosatetraenoic acid to form eicosapentaenoic acid (EPA) in the omega-3 pathway. The expression of Δ5Des was highly up-regulated in cultures grown in low temperature (18 °C) than the cultures grown in (22 °C) (Figure 3). Finally, Δ4Des adds a double bond to docosapentaenoic acid (DPA) to form DHA in the pathway. The expression of Δ4Des was highly up-regulated in cultures grown in low temperature (18 °C) than the cultures grown in (22 °C) (Figure 3). The expression of two front end desaturases (Δ4Des & Δ5Des) is highly favorable for the cultures grown at low temperature indicates the high demand of EPA and DHA at the cellular level for the maintenance of cell membrane. Temperature shift favors the synthesis of long-chain PUFAs particularly EPA and DHA in microalgae for the adaptation of membrane lipids and internal organelles toward changing environment. Interestingly the mRNA expression of respective desaturases was highly similar to the fatty acid profile of microalgal cells grown at low temperatures. In RSM treatments, microalga grown under low-temperature treatments (such as R3, R4, R6, and R20) showed higher accumulation of EPA and DHA in their fatty acid profile (Supplementary Table 1).