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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
The four most important oilseed crops are soybean, oil palm, rapeseed, and sunflower which contain four fatty acids, that is, linoleic acid (18:2 cis-9,12), palmitic acid (16:0), lauric acid (12:0), and oleic acid (18:1), abundantly in their seeds. However, there are five major fatty acids in plants which constitute 90% of the acyl chains of the glycerolipids of almost all membranes found in plants. These fatty acids have 16 or 18 carbons in the chains (i.e., 18:1, 18:2, 18:3, 16:0, and in some species, 16:3), and they contain one to three cis double bonds (Thelen and Ohlrogge, 2001). The de novo biosynthesis of fatty acid is catalyzed by acetyl-CoA carboxylase and the fatty acid synthase known as Kennedy Pathway (Bates, et al., 2013). The unsaturated fatty acids of 4–18 carbons are synthesized in plastid and the fatty acyl chain then is attached to the acyl carrier protein of the fatty acid synthase complex. The fatty acyl chain is released from the carrier protein by thioesterase. Once exported from the plastid, acyl-Coenzyme A (acyl-CoA) synthetase combines fatty acid chains to CoA-forming acyl-CoA on the outer membrane of plastids.
Biochemistry
Published in Ronald Fayer, Lihua Xiao, Cryptosporidium and Cryptosporidiosis, 2007
Free fatty acids have to be activated to form acyl-ACP or acyl-CoA esters before they can enter subsequent metabolic pathways. In addition to FAS and PKS, which can directly activate fatty acids to form acyl-ACP by the AL domains, Cryptosporidium also has three discrete fatty acid-CoA ligases (ACLs) to make fatty acyl-CoAs. Because uncontained fatty acyl-CoA molecules may act as a detergent that is harmful to cell membranes, they have to be used immediately or stored or transported via an acyl-CoA binding protein (ACBP). Cryptosporidium has a single, “long-type” ACBP (CpACBP1) that is fused with an ankyrin-repeat sequence and prefers medium- to long-chain fatty acyl-CoAs as substrates (Zeng et al., 2006). CpACBP1 is chiefly localized to the parasitophorous vacuole membrane (PVM), rather than in the intracellular parasites or free sporozoites. Whether CpACBP1 is involved in the membrane remodeling in PVM or fatty acid transport across PVM remains to be elucidated. In addition to ACBP, Cryptosporidium also encodes two oxysterol-binding protein-related proteins (CpORP1 and 2), in which CpORP1 was also localized to PVM (Zeng and Zhu, 2006). Both CpORPs can bind to all species of phosphatidylinositol phosphates (PIPs). Whether and how CpORPs are involved in the regulation and transport of sterols or other lipids is not fully understood. However, the presence of ACB and ORP proteins in PVM indicates that this membrane barrier between parasite and intestinal lumen is directly involved in lipid transport and remodeling during the parasite’s intracellular development.
Delving through Quorum Sensing and CRISPRi Strategies for Enhanced Surfactin Production
Published in R.Z. Sayyed, Microbial Surfactants, 2022
Shireen Adeeb Mujtaba Ali, R. Z. Sayyed, M. S. Reddy, Hesham El Enshasy, Bee Hameedal
The biosynthetic pathway of surfactin production is divided into three steps (Wang et al. 2019), i.e., formation of fatty acyl-CoA by activating fatty acids via fatty acyl-CoA ligase.biosynthesis of amino acids—L-Valine, L-Leucine, L-Aspartate, L-Glutamate.assembly of seven amino acids on fatty acyl-CoA via surfactin synthetase.
Effect of photo-autotrophic cultural conditions on the biomass productivity and composition of Chlorella vulgaris
Published in Biofuels, 2022
Norazela Nordin, Norjan Yusof, Syafiqah Md Nadzir, Mohd Zulkhairi Mohd Yusoff, Mohd Ali Hassan
Even though lipid accumulation was proven to increase during nitrogen-limited cultures, the enhanced lipid accumulation is concomitant with lower biomass and overall lipid productivities. When grown under nitrogen limitation, Chlorella vulgaris is expected to give an increased lipid yield at the expense of cellular growth, because under such conditions, the protein synthesis required for cell growth is inhibited, leaving an excess of carbon from photosynthesis, which is then redirected to the metabolic paths of lipid storage and starch production [5]. In the absence of NO3−, Chlorella vulgaris changed its energy storage from starch to lipid in preparation for prolonged environmental stress. As noted in a previous study, nitrogen limitation results in cellular changes including acyl hydrolase activation, reduction of the cellular content of the thylakoid membrane, and induction of phospholipid hydrolysis [6]. These modifications were found to cause an increase in the intracellular fatty acid acyl-CoA while propagating the nitrogen limitation to activate the diacylglycerol acyltransferase, which then converts acyl-CoA to TAG. Consequently, nitrogen deficiency leads to an increase in lipid and TAG contents in microalgae cells.
Microbial and functional characterization of granulated sludge from full-scale UASB thermophilic reactor applied to sugarcane vinasse treatment
Published in Environmental Technology, 2022
Franciele Pereira Camargo, Isabel Kimiko Sakamoto, Tiago Palladino Delforno, Cédric Midoux, Iolanda Cristina Silveira Duarte, Edson Luiz Silva, Ariane Bize, Maria Bernadete Amâncio Varesche
The K01897 (0.081%), a long-chain acyl-CoA synthetase, could be related to several genera, such as Crocinitomix (14.1%), Hylemonella (12.0%), Sulfurimonas (10.5%), Marinobacter (6.1%), Marinospirillum (2.4%) and Pseudomonas (1.6%). It acts in the fatty acids biosynthesis from Acetyl-CoA in a wide range of long-chain saturated and unsaturated fatty acids, binding them to a CoA molecule, generating a diphosphate and a long-chain fatty acyl-CoA, requiring an ATP molecule in the process. In the same way, it can also acts in the Hexadecanoate degradation in the Fatty acids degradation pathway. The K06445 (0.0057%), acts in the same pathways mentioned, as an acyl-CoA dehydrogenase.
Assessing the potential of nutrient deficiency for enhancement of biodiesel production in algal resources
Published in Biofuels, 2023
Maria Hasnain, Zainul Abideen, Saud Hashmi, Shagufta Naz, Neelma Munir
Algal feedstock has several advantages over terrestrial crops. Algae are growing quickly and can be continuously harvested. Algae cultures are not affected by weather conditions and do not depend on soil fertility and freshwater [7]. Rather, these can be cultivated in wastewater or saline water as well. Algae cultures have been reported to produce up to 10 fold more oil as compared to field grown crops [8]. It can be calculated that microalgae cultures photosynthesize up to 2 kg of CO2/kg of algal biomass [9]. Algae have up to 5% photo-conversion efficiency, contrarily for terrestrial crops in temperate climates it is just 1% [10]. But, production costs of algae based oils are a major disadvantage contradicting marketing of this promising approach. Drivers of costs are construction of the production site, land use, energy consumption, and maintenance [11]. From this list it is obvious that costs have to be calculated individually depending upon the location of the algae production site [12]. So, there is need to identify a suitable approach to enhance lipid content and reduce environmental impressions and costs of the overall process. Biological activities of algae highly depend on culture conditions, as the unfavorable conditions (nutrient deficiency, change in pH, temperature and light) will modify the metabolite composition of algae cells such as the content of carbohydrates, proteins, chlorophyll and lipids [13, 14]. In the literature many approaches can be found that are aiming at increased carbohydrate and lipid contents of algae [15]. Under nutrient deficiency an increased cellular carbohydrate and lipid content can be found (Table 1). Compared to the other nutrients, nitrogen, phosphorus and iron are the most effective factors causing this effect in algae. Nutrient deficiency in algae inhibits cell division and, thus, decreases in growth rate and physiological performance. An inhibition of protein synthesis and a decrease of photosynthetic rate have been observed in algal species [13]. With respect to oil production it is important that a stimulation of diacylglycerol acyltransferase activity has been observed. This enzyme synthesizes triglycerides from acyl-CoA. Overstimulation of this activity will result accumulation of storage lipids [14]. Nitrogen is a substantial component found in the proteins and DNA. For that reason, cells require nitrogen to grow and reproduce. Nitrogen is the solitary most essential nutrient related with lipid metabolism in algae and leads to in the accumulation of lipids [23].