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Ugya AY, Hasan DB, Ari HA, Sheng Y, Chen H, Wang Q. Antibiotic synergistic effect surge bioenergy potential and pathogen resistance of Chlorella variabilis biofilm. ENVIRONMENTAL RESEARCH 2024; 259:119521. [PMID: 38960350 DOI: 10.1016/j.envres.2024.119521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 06/21/2024] [Accepted: 06/29/2024] [Indexed: 07/05/2024]
Abstract
Tetracycline (TC) and ciprofloxacin (CF) induce a synergistic effect that alters the biochemical composition, leading to a decrease in the growth and photosynthetic efficiency of microalgae. But the current study provides a novel insight into stress-inducing techniques that trigger a change in macromolecules, leading to an increase in the bioenergy potential and pathogen resistance of Chlorella variabilis biofilm. The study revealed that in a closed system, a light intensity of 167 μmol/m2/s causes 93.5% degradation of TC and 16% degradation of CF after 7 days of exposure, hence availing the products for utilization by C. variabilis biofilm. The resistance to pathogens invasion was linked to 85% and 40% increase in the expression level of photosystem II oxygen-evolving enhancer protein 3 (PsbQ), and mitogen activated kinase (MAK) respectively. The results also indicate that a surge in light intensity triggers 49% increase in the expression level of lysophosphatidylcholine (LPC) (18:2), which is an important lipidomics that can easily undergo transesterification into bioenergy. The thermogravimetric result indicates that the biomass sample of C. variabilis biofilm cultivated under light intensity of 167 μmol/m2/s produces a higher residual mass of 45.5% and 57.5 under air and inert conditions, respectively. The Fourier transform infrared (FTIR) indicates a slight shift in the major functional groups, while the energy-dispersive X-ray spectroscopy (SEM-EDS) and X-ray fluorescence (XRF) indicate clear differences in the morphology and elemental composition of the biofilm biomass in support of the increase bioenergy potential of C. variabilis biofilm. The current study provides a vital understanding of a innovative method of cultivation of C. variabilis biofilm, which is resistant to pathogens and controls the balance between fatty acid and TAG synthesis leading to surge in bioenergy potential and environmental sustainability.
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Affiliation(s)
- Adamu Yunusa Ugya
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China; Henan Key Laboratory of Synthetic Biology and Biomanufacturing, Henan University, Kaifeng, China; Department of Environmental Management, Kaduna State University, Kaduna State, Nigeria
| | - Diya'uddeen Basheer Hasan
- Centre for Energy Research and Training (CERT), Ahmadu Bello University, Zaria, Kaduna State, Nigeria
| | | | - Yangyang Sheng
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Hui Chen
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China; Henan Key Laboratory of Synthetic Biology and Biomanufacturing, Henan University, Kaifeng, China
| | - Qiang Wang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China; Henan Key Laboratory of Synthetic Biology and Biomanufacturing, Henan University, Kaifeng, China.
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Dai JL, He YJ, Chen HH, Jiang JG. Dual Roles of Two Malic Enzymes in Lipid Biosynthesis and Salt Stress Response in Dunaliella salina. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023. [PMID: 37906521 DOI: 10.1021/acs.jafc.3c04810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Triacylglycerols (TAG) from microalgae can be used as feedstocks for biofuel production to address fuel shortages. Most of the current research has focused on the enzymes involved in TAG biosynthesis. In this study, the effects of malic enzyme (ME), which provides precursor and reducing power for TAG biosynthesis, on biomass and lipid accumulation and its response to salt stress in Dunaliella salina were investigated. The overexpression of DsME1 and DsME2 improved the lipid production, which reached 0.243 and 0.253 g/L and were 30.5 and 36.3% higher than wild type, respectively. The transcript levels of DsME1 and DsME2 increased with increasing salt concentration (0, 1, 2, 3, and 4.5 mol/L NaCl), indicating that DsMEs participated in the salt stress response in D. salina. It was found that cis-acting elements associated with the salt stress response were present on the promoters of two DsMEs. The deletion of the MYB binding site (MBS) on the DsME2 promoter confirmed that MBS drives the expression of DsME2 to participate in osmotic regulation in D. salina. In conclusion, MEs are the critical enzymes that play pivotal roles in lipid accumulation and osmotic regulation.
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Affiliation(s)
- Jv-Liang Dai
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Yu-Jing He
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Hao-Hong Chen
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Jian-Guo Jiang
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
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Mata MT, Cameron H, Avalos V, Riquelme C. Identification and Characterization of a Novel Microalgal Strain from the Antofagasta Coast Tetraselmis marina AC16-MESO (Chlorophyta) for Biotechnological Applications. PLANTS (BASEL, SWITZERLAND) 2023; 12:3372. [PMID: 37836113 PMCID: PMC10574681 DOI: 10.3390/plants12193372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 08/07/2023] [Accepted: 08/17/2023] [Indexed: 10/15/2023]
Abstract
The wide rocky coastline of the Antofagasta hosts an intertidal ecosystem in which the species that inhabit it are routinely exposed to a wide range of physical and chemical conditions and have therefore evolved to tolerate extremes. In the search for new species of potential biotechnological interest with adaptations to a wide range of environmental conditions, the isolation and characterization of microalgae from these ecosystems is of great interest. Here, a new microalgal strain, Tetraselmis marina AC16-MESO, is described, which was isolated from a biofilm collected on the intertidal rocks of the Antofagasta coast (23°36'57.2″ S, 70°23'33.8″ W). In addition to the morphological characterization, 18S and ITS sequence as well as ITS-2 secondary structure analysis revealed an identity of 99.76% and 100% with the species Tetraselmis marina, respectively. The analyses of the culture characteristics and biochemical content showed similarities with other strains that are frequently used in aquaculture, such as the species Tetraselmis suecica. In addition, it is tolerant of a wide range of salinities, thus allowing its culture in water of varying quality. On the other hand, added to these characteristics, the results of the improvement of the lipid content in stressful situations of salinity observed in this study, together with other antecedents such as the potential in bioremediation already published for this strain by the same research group, present a clear example of its biotechnological plasticity. It is noteworthy that this strain, due to its characteristics, allows easy collection of its biomass by decantation and, therefore, a more cost-efficient harvesting than for other microalgal strains. Therefore, this new strain of Tetraselmis marina, first report of this species in Chile, and its morphologically, molecularly and biochemically description, presents promising characteristics for its use in biotechnology and as feed for aquaculture.
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Affiliation(s)
- Maria Teresa Mata
- Department of Biotechnology, Faculty of Marine Sciences and Biological Resources, University of Antofagasta, Antofagasta 1240000, Chile
- Centro de Bioinnovación de Antofagasta (CBIA), Faculty of Marine Sciences and Biological Resources, University of Antofagasta, Antofagasta 1240000, Chile; (H.C.); (V.A.); (C.R.)
| | - Henry Cameron
- Centro de Bioinnovación de Antofagasta (CBIA), Faculty of Marine Sciences and Biological Resources, University of Antofagasta, Antofagasta 1240000, Chile; (H.C.); (V.A.); (C.R.)
| | - Vladimir Avalos
- Centro de Bioinnovación de Antofagasta (CBIA), Faculty of Marine Sciences and Biological Resources, University of Antofagasta, Antofagasta 1240000, Chile; (H.C.); (V.A.); (C.R.)
| | - Carlos Riquelme
- Centro de Bioinnovación de Antofagasta (CBIA), Faculty of Marine Sciences and Biological Resources, University of Antofagasta, Antofagasta 1240000, Chile; (H.C.); (V.A.); (C.R.)
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Kondo M, Aoki M, Hirai K, Ito R, Tsuzuki M, Sato N. Plastoquinone Lipids: Their Synthesis via a Bifunctional Gene and Physiological Function in a Euryhaline Cyanobacterium, Synechococcus sp. PCC 7002. Microorganisms 2023; 11:1177. [PMID: 37317151 DOI: 10.3390/microorganisms11051177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 04/27/2023] [Accepted: 04/28/2023] [Indexed: 06/16/2023] Open
Abstract
Eukaryotic photosynthetic organisms synthesize triacylglycerols, which are crucial physiologically as major carbon and energy storage compounds and commercially as food oils and raw materials for carbon-neutral biofuel production. TLC analysis has revealed triacylglycerols are present in several cyanobacteria. However, mass spectrometric analysis has shown that freshwater cyanobacterium, Synechocystis sp. PCC 6803, contains plastoquinone-B and acyl plastoquinol with triacylglycerol-like TLC mobility, concomitantly with the absence of triacylglycerol. Synechocystis contains slr2103, which is responsible for the bifunctional synthesis of plastoquinone-B and acyl plastoquinol and also for NaCl-stress acclimatizing cell growth. However, information is limited on the taxonomical distribution of these plastoquinone lipids, and their synthesis genes and physiological roles in cyanobacteria. In this study, a euryhaline cyanobacterium, Synechococcus sp. PCC 7002, shows the same plastoquinone lipids as those in Synechocystis, although the levels are much lower than in Synechocystis, triacylglycerol being absent. Furthermore, through an analysis of a disruptant to the homolog of slr2103 in Synechococcus, it is found that the slr2103 homolog in Synechococcus, similar to slr2103 in Synechocystis, contributes bifunctionally to the synthesis of plastoquinone-B and acyl plastoquinol; however, the extent of the contribution of the homolog gene to NaCl acclimatization is smaller than that of slr2103 in Synechocystis. These observations suggest strain- or ecoregion-dependent development of the physiological roles of plastoquinone lipids in cyanobacteria and show the necessity to re-evaluate previously identified cyanobacterial triacylglycerol through TLC analysis with mass spectrometric techniques.
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Affiliation(s)
- Mimari Kondo
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Motohide Aoki
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Kazuho Hirai
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Ryo Ito
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Mikio Tsuzuki
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Norihiro Sato
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
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Nakayasu M, Amano M, Tanaka T, Shimakawa G, Matsuda Y. Different Responses of Photosynthesis to Nitrogen Starvation Between Highly Oil-Accumulative Diatoms, Fistulifera solaris and Mayamaea sp. JPCC CTDA0820. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2023; 25:272-280. [PMID: 36856914 DOI: 10.1007/s10126-023-10203-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 02/19/2023] [Indexed: 05/06/2023]
Abstract
Highly oil-accumulative diatoms are expected to be a promising biomass for the production of biofuel. To harvest the diatom oils at high yields, it is critical to elucidate the relationship of oil accumulation with photosynthesis under fluctuating environmental conditions. Here, we characterized the physiological responses of the growth and photosynthesis in the mesophilic diatom Fistulifera solaris and the cold-tolerant one Mayamaea sp. JPCC CTDA0820 to nitrogen starvation, one of the most notable abiotic stresses, where most eukaryotic algae decrease their photosynthetic activity and accumulate oil in the cells. While F. solaris started showing growth retardation at NaNO3 levels less than 50% of a normal F/2 artificial seawater (ASW) medium, Mayamaea sp. sustained normal growth even at a NaNO3 level 10% of normal F/2ASW, indicating the sharp contrast of nitrogen requirement between these two diatom species. In the transition from 100 to 0% nitrogen conditions in the modified F/2ASW, F. solaris showed a clear suppression of chlorophyll (Chl)-based photosynthetic O2 evolution rate and relative electron transport rate at photosystem II, which were negatively correlated to the capacity of non-photochemical quenching. Meanwhile, there was no change in these Chl-based parameters observed in nitrogen-starved Mayamaea sp. Instead, Mayamaea sp. showed a significant decrease in the Chl a amount per cells. These data suggested the occurrence of two types of photosynthetic responses to nitrogen starvation in oleaginous diatoms; that is, (1) suppression of photosynthetic activity per Chl with enhancing heat dissipation of excess light energy and (2) synchronous suppression of cellular photosynthetic activity with Chl amounts.
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Affiliation(s)
- Mana Nakayasu
- Department of Bioscience, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen-Uegahara, Sanda, Hyogo, 669-1330, Japan
| | - Momoka Amano
- Department of Bioscience, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen-Uegahara, Sanda, Hyogo, 669-1330, Japan
| | - Tsuyoshi Tanaka
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Koganei, Tokyo, 184-8588, Japan
| | - Ginga Shimakawa
- Department of Bioscience, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen-Uegahara, Sanda, Hyogo, 669-1330, Japan.
| | - Yusuke Matsuda
- Department of Bioscience, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen-Uegahara, Sanda, Hyogo, 669-1330, Japan.
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Kim S, Lee KR, Suh MC. Ectopic Expression of Perilla frutescens WRI1 Enhanced Storage Oil Accumulation in Nicotiana benthamiana Leaves. PLANTS (BASEL, SWITZERLAND) 2023; 12:1081. [PMID: 36903941 PMCID: PMC10005204 DOI: 10.3390/plants12051081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/14/2023] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
Vegetable oils are indispensable in human and animal diets and have been widely used for the production of detergents, lubricants, cosmetics, and biofuels. The seeds of an allotetraploid Perilla frutescens contain approximately 35 to 40% oils with high levels of polyunsaturated fatty acids (PUFAs). WRINKELD1 (WRI1) encoding an AP2/ERF-type transcription factor is known to upregulate the expression of genes involved in glycolysis and fatty acid biosynthesis and TAG assembly. In this study, two WRI1 isoforms, PfWRI1A, and PfWRI1B were isolated from Perilla and predominantly expressed in developing Perilla seeds. The fluorescent signals from PfWRI1A:eYFP and PfWRI1B:eYFP driven by the CaMV 35S promoter were detected in the nucleus of the Nicotiana benthamiana leaf epidermis. Ectopic expression of each of PfWRI1A and PfWRI1B increased the levels of TAG by approximately 2.9- and 2.7-fold in N. benthamiana leaves and particularly, the enhanced levels (mol%) of C18:2, and C18:3 in the TAGs were prominent with the concomitant reduction in the amounts of saturated fatty acids. The expression levels of NbPl-PKβ1, NbKAS1, and NbFATA, which were known to be target genes of WRI1, significantly increased in tobacco leaves overexpressing PfWRI1A or PfWRI1B. Therefore, newly characterized PfWRI1A and PfWRI1B can be potentially useful for the enhanced accumulation of storage oils with increased PUFAs in oilseed crops.
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Affiliation(s)
- Semi Kim
- Department of Life Science, Sogang University, Seoul 04107, Republic of Korea
| | - Kyeong-Ryeol Lee
- Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, Jeonju 54875, Republic of Korea
| | - Mi Chung Suh
- Department of Life Science, Sogang University, Seoul 04107, Republic of Korea
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Hoffmann DY, Shachar-Hill Y. Do betaine lipids replace phosphatidylcholine as fatty acid editing hubs in microalgae? FRONTIERS IN PLANT SCIENCE 2023; 14:1077347. [PMID: 36743481 PMCID: PMC9892843 DOI: 10.3389/fpls.2023.1077347] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 01/04/2023] [Indexed: 06/18/2023]
Abstract
Acyl editing refers to a deacylation and reacylation cycle on a lipid, which allows for fatty acid desaturation and modification prior to being removed and incorporated into other pools. Acyl editing is an important determinant of glycerolipid synthesis and has been well-characterized in land plants, thus this review begins with an overview of acyl editing in plants. Much less is known about acyl editing in algae, including the extent to which acyl editing impacts lipid synthesis and on which lipid substrate(s) it occurs. This review compares what is known about acyl editing on its major hub phosphatidylcholine (PC) in land plants with the evidence for acyl editing of betaine lipids such as diacylglyceryltrimethylhomoserine (DGTS), the structural analog that replaces PC in several species of microalgae. In land plants, PC is also known to be a major source of fatty acids and diacylglycerol (DAG) for synthesis of the neutral lipid triacylglycerol (TAG). We review the evidence that DGTS contributes substantially to TAG accumulation in algae as a source of fatty acids, but not as a precursor to DAG. We conclude with evidence of acyl editing on other membrane lipid substrates in plants and algae apart from PC or DGTS, and discuss future analyses to elucidate the role of DGTS and other betaine lipids in acyl editing in microalgae.
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Kryvenda A, Tischner R, Steudel B, Griehl C, Armon R, Friedl T. Testing for terrestrial and freshwater microalgae productivity under elevated CO 2 conditions and nutrient limitation. BMC PLANT BIOLOGY 2023; 23:27. [PMID: 36635620 PMCID: PMC9837994 DOI: 10.1186/s12870-023-04042-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 01/03/2023] [Indexed: 06/17/2023]
Abstract
BACKGROUND Microalgae CO2 fixation results in the production of biomass rich in high-valuable products, such as fatty acids and carotenoids. Enhanced productivity of valuable compounds can be achieved through the microalgae's ability to capture CO2 efficiently from sources of high CO2 contents, but it depends on the species. Culture collections of microalgae offer a wide variety of defined strains. However, an inadequate understanding of which groups of microalgae and from which habitats they originate offer high productivity under increased CO2 concentrations hampers exploiting microalgae as a sustainable source in the bioeconomy. RESULTS A large variety of 81 defined algal strains, including new green algal isolates from various terrestrial environments, were studied for their growth under atmospheres with CO2 levels of 5-25% in air. They were from a pool of 200 strains that had been pre-selected for phylogenetic diversity and high productivity under ambient CO2. Green algae from terrestrial environments exhibited enhanced growth up to 25% CO2. In contrast, in unicellular red algae and stramenopile algae, which originated through the endosymbiotic uptake of a red algal cell, growth at CO2 concentrations above 5% was suppressed. While terrestrial stramenopile algae generally tolerated such CO2 concentrations, their counterparts from marine phytoplankton did not. The tests of four new strains in liquid culture revealed enhanced biomass and chlorophyll production under elevated CO2 levels. The 15% CO2 aeration increased their total carotenoid and fatty acid contents, which were further stimulated when combined with the starvation of macronutrients, i.e., less with phosphate and more with nitrogen-depleted culture media. CONCLUSION Green algae originating from terrestrial environments, Chlorophyceae and Trebouxiophyceae, exhibit enhanced productivity of carotenoids and fatty acids under elevated CO2 concentrations. This ability supports the economic and sustainable production of valuable compounds from these microalgae using inexpensive sources of high CO2 concentrations, such as industrial exhaust fumes.
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Affiliation(s)
- Anastasiia Kryvenda
- Albrecht-von-Haller-Institute for Plant Sciences, Department of Experimental Phycology and Culture Collection of Algae (SAG), University of Göttingen, Nikolausberger Weg 18, 37073 Göttingen, Germany
- Present address: Staatliche Betriebsgesellschaft für Umwelt und Landwirtschaft, 01683 Nossen, Germany
| | - Rudolf Tischner
- Albrecht-von-Haller-Institute for Plant Sciences, Department of Experimental Phycology and Culture Collection of Algae (SAG), University of Göttingen, Nikolausberger Weg 18, 37073 Göttingen, Germany
| | - Bastian Steudel
- Albrecht-von-Haller-Institute for Plant Sciences, Department of Experimental Phycology and Culture Collection of Algae (SAG), University of Göttingen, Nikolausberger Weg 18, 37073 Göttingen, Germany
- Present address: Department of Health and Environmental Sciences, Xi’an Jiaotong-Liverpool University (XJTLU), Suzhou, 215123 Jiangsu Province China
| | - Carola Griehl
- Department of Applied Biosciences and Process Technology, Competence Center Algal Biotechnology, Anhalt University of Applied Sciences, 06366 Köthen, Germany
| | - Robert Armon
- Technion-Israel Institute of Technology, Faculty of Civil and Environmental Engineering, 32000 Haifa, Israel
| | - Thomas Friedl
- Albrecht-von-Haller-Institute for Plant Sciences, Department of Experimental Phycology and Culture Collection of Algae (SAG), University of Göttingen, Nikolausberger Weg 18, 37073 Göttingen, Germany
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Kondo M, Aoki M, Hirai K, Sagami T, Ito R, Tsuzuki M, Sato N. slr2103, a homolog of type-2 diacylglycerol acyltransferase genes, for plastoquinone-related neutral lipid synthesis and NaCl-stress acclimatization in a cyanobacterium, Synechocystis sp. PCC 6803. FRONTIERS IN PLANT SCIENCE 2023; 14:1181180. [PMID: 37180399 PMCID: PMC10171310 DOI: 10.3389/fpls.2023.1181180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 04/10/2023] [Indexed: 05/16/2023]
Abstract
A cyanobacterium, Synechocystis sp. PCC 6803, contains a lipid with triacylglycerol-like TLC mobility but its identity and physiological roles remain unknown. Here, on ESI-positive LC-MS2 analysis, it is shown that the triacylglycerol-like lipid (lipid X) is related to plastoquinone and can be grouped into two subclasses, Xa and Xb, the latter of which is esterified by 16:0 and 18:0. This study further shows that a Synechocystis homolog of type-2 diacylglycerol acyltransferase genes, slr2103, is essential for lipid X synthesis: lipid X disappears in a Synechocystis slr2103-disruptant whereas it appears in an slr2103-overexpressing transformant (OE) of Synechococcus elongatus PCC 7942 that intrinsically lacks lipid X. The slr2103 disruption causes Synechocystis cells to accumulate plastoquinone-C at an abnormally high level whereas slr2103 overexpression in Synechococcus causes the cells to almost completely lose it. It is thus deduced that slr2103 encodes a novel acyltransferase that esterifies 16:0 or 18:0 with plastoquinone-C for the synthesis of lipid Xb. Characterization of the slr2103-disruptant in Synechocystis shows that slr2103 contributes to sedimented-cell growth in a static culture, and to bloom-like structure formation and its expansion by promoting cell aggregation and floatation upon imposition of saline stress (0.3-0.6 M NaCl). These observations provide a basis for elucidation of the molecular mechanism of a novel cyanobacterial strategy to acclimatize to saline stress, and one for development of a system of seawater-utilization and economical harvesting of cyanobacterial cells with high-value added compounds, or blooming control of toxic cyanobacteria.
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Metabolomic analysis reveals the responses of docosahexaenoic-acid-producing Schizochytrium under hyposalinity conditions. ALGAL RES 2023. [DOI: 10.1016/j.algal.2023.102987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Expression profile of genes associated with the accumulation of triacylglycerol (TAG) in Auxenochlorella protothecoides KP7 under alkaline pH and nitrogen starvation conditions. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2023. [DOI: 10.1016/j.bcab.2023.102628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Morales-Pineda M, García-Gómez ME, Bedera-García R, García-González M, Couso I. CO 2 Levels Modulate Carbon Utilization, Energy Levels and Inositol Polyphosphate Profile in Chlorella. PLANTS (BASEL, SWITZERLAND) 2022; 12:plants12010129. [PMID: 36616258 PMCID: PMC9823770 DOI: 10.3390/plants12010129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/20/2022] [Accepted: 12/22/2022] [Indexed: 05/15/2023]
Abstract
Microalgae have a growing recognition of generating biomass and capturing carbon in the form of CO2. The genus Chlorella has especially attracted scientists' attention due to its versatility in algal mass cultivation systems and its potential in mitigating CO2. However, some aspects of how these green microorganisms respond to increasing concentrations of CO2 remain unclear. In this work, we analyzed Chlorella sorokiniana and Chlorella vulgaris cells under low and high CO2 levels. We monitored different processes related to carbon flux from photosynthetic capacity to carbon sinks. Our data indicate that high concentration of CO2 favors growth and photosynthetic capacity of the two Chlorella strains. Different metabolites related to the tricarboxylic acid cycle and ATP levels also increased under high CO2 concentrations in Chlorella sorokiniana, reaching up to two-fold compared to low CO2 conditions. The signaling molecules, inositol polyphosphates, that regulate photosynthetic capacity in green microalgae were also affected by the CO2 levels, showing a deep profile modification of the inositol polyphosphates that over-accumulated by up to 50% in high CO2 versus low CO2 conditions. InsP4 and InsP6 increased 3- and 0.8-fold, respectively, in Chlorella sorokiniana after being subjected to 5% CO2 condition. These data indicate that the availability of CO2 could control carbon flux from photosynthesis to carbon storage and impact cell signaling integration and energy levels in these green cells. The presented results support the importance of further investigating the connections between carbon assimilation and cell signaling by polyphosphate inositols in microalgae to optimize their biotechnological applications.
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Transcriptome Analysis Reveals the Involvement of Alternative Splicing in the Nitrogen Starvation Response of Chlamydomonas reinhardtii. Processes (Basel) 2022. [DOI: 10.3390/pr10122719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Alternative splicing (AS) is a regulatory mechanism of post-transcriptional regulation that plays an important role in plant response to abiotic stresses. However, corresponding research involving the mechanism of AS in the nitrogen starvation response of C. reinhardtii is rare. This study performed a comprehensive and systematic analysis of AS events in C. reinhardtii at nine time points (0 h, 10 m, 30 m, 1 h, 6 h, 8 h, 24 h, and 48 h) under nitrogen starvation. It used STAR and rMATS tools to identify and quantify the probability of the AS event happening through the transcriptome high-throughput sequencing data. A total of 5806 AS events in 3500 genes were identified, and the retained intron and skipped exon were considered the main AS types. The genes related to the AS event in nitrogen starvation were mainly involved in spliceosome and transporter and enriched in the citrate cycle and fatty acid degradation pathways. These results suggested that AS may play an important role in the nitrogen starvation response in C. reinhardtii, and provided insights into post-transcriptional regulation under nitrogen starvation.
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14
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Goemann CL, Wilkinson R, Henriques W, Bui H, Goemann HM, Carlson RP, Viamajala S, Gerlach R, Wiedenheft B. Genome sequence, phylogenetic analysis, and structure-based annotation reveal metabolic potential of Chlorella sp. SLA-04. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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15
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Ding W, Liu J. Rutin Stimulates the Green Alga Chromochloris zofingiensis for Improved Biomass and Astaxanthin Production. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:13626-13636. [PMID: 36219673 DOI: 10.1021/acs.jafc.2c04928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Chromochloris zofingiensis represents a potential algal producer of the value-added ketocarotenoid astaxanthin. Here, rutin, a low-cost flavonoid compound, was evaluated regarding its roles in C. zofingiensis production under astaxanthin-inducing conditions via physiological, biochemical, and transcriptomics analyses. The rutin treatment allowed C. zofingiensis to achieve 81.2% more biomass and 20.5% greater astaxanthin content under nitrogen deprivation, leading to more than doubled astaxanthin production. The rutin-treated C. zofingiensis had higher levels of chlorophylls, proteins, and lipids and lower carbohydrate level than the control. Rutin promoted the intracellular abscisic acid (ABA) level, which could be restored by the ABA biosynthesis inhibitor, accompanied by the restoration of biomass concentration and astaxanthin content. The application of exogenous ABA to C. zofingiensis also furthered biomass concentration and astaxanthin accumulation. Together with the comparative transcriptomics analysis, our study provides implications into the involvement of ABA in rutin-mediated stimulation of C. zofingiensis growth and astaxanthin accumulation and highlights a feasible strategy of combining stress and chemical induction for improved microalgal production.
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Affiliation(s)
- Wei Ding
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
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16
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Zhu Z, Sun J, Fa Y, Liu X, Lindblad P. Enhancing microalgal lipid accumulation for biofuel production. Front Microbiol 2022; 13:1024441. [PMID: 36299727 PMCID: PMC9588965 DOI: 10.3389/fmicb.2022.1024441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 09/26/2022] [Indexed: 11/13/2022] Open
Abstract
Microalgae have high lipid accumulation capacity, high growth rate and high photosynthetic efficiency which are considered as one of the most promising alternative sustainable feedstocks for producing lipid-based biofuels. However, commercialization feasibility of microalgal biofuel production is still conditioned to the high production cost. Enhancement of lipid accumulation in microalgae play a significant role in boosting the economics of biofuel production based on microalgal lipid. The major challenge of enhancing microalgal lipid accumulation lies in overcoming the trade-off between microalgal cell growth and lipid accumulation. Substantial approaches including genetic modifications of microalgal strains by metabolic engineering and process regulations of microalgae cultivation by integrating multiple optimization strategies widely applied in industrial microbiology have been investigated. In the present review, we critically discuss recent trends in the application of multiple molecular strategies to construct high performance microalgal strains by metabolic engineering and synergistic strategies of process optimization and stress operation to enhance microalgal lipid accumulation for biofuel production. Additionally, this review aims to emphasize the opportunities and challenges regarding scaled application of the strategic integration and its viability to make microalgal biofuel production a commercial reality in the near future.
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Affiliation(s)
- Zhi Zhu
- The Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province, School of Life Sciences, Jiangsu Normal University, Xuzhou, China
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, China
- CAS Key Laboratory of Bio-Based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Jing Sun
- The Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province, School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Yun Fa
- CAS Key Laboratory of Bio-Based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Xufeng Liu
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden
- *Correspondence: Xufeng Liu,
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden
- Peter Lindblad,
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17
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Chatterjee P, Schafran P, Li FW, Meeks JC. Nostoc Talks Back: Temporal Patterns of Differential Gene Expression During Establishment of Anthoceros-Nostoc Symbiosis. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2022; 35:917-932. [PMID: 35802132 DOI: 10.1094/mpmi-05-22-0101-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Endosymbiotic associations between hornworts and nitrogen-fixing cyanobacteria form when the plant is limited for combined nitrogen (N). We generated RNA-seq data to examine temporal gene expression patterns during the culturing of N-starved Anthoceros punctatus in the absence and the presence of symbiotic cyanobacterium Nostoc punctiforme. In symbiont-free A. punctatus gametophytes, N starvation caused downregulation of chlorophyll content and chlorophyll fluorescence characteristics as well as transcription of photosynthesis-related genes. This downregulation was reversed in A. punctatus cocultured with N. punctiforme, corresponding to the provision by the symbiont of N2-derived NH4+, which commenced within 5 days of coculture and reached a maximum by 14 days. We also observed transient increases in transcription of ammonium and nitrate transporters in a N. punctiforme-dependent manner as well as that of a SWEET transporter that was initially independent of N2-derived NH4+. The temporal patterns of differential gene expression indicated that N. punctiforme transmits signals that impact gene expression to A. punctatus both prior to and after its provision of fixed N. This study is the first illustrating the temporal patterns of gene expression during establishment of an endosymbiotic nitrogen-fixing association in this monophyletic evolutionary lineage of land plants. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Poulami Chatterjee
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, U.S.A
| | - Peter Schafran
- Boyce Thompson Institute, Ithaca, NY 14853, U.S.A
- Plant Biology Section, Cornell University, Ithaca, NY 14953, U.S.A
| | - Fay-Wei Li
- Boyce Thompson Institute, Ithaca, NY 14853, U.S.A
- Plant Biology Section, Cornell University, Ithaca, NY 14953, U.S.A
| | - John C Meeks
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, U.S.A
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18
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Zhou W, Ji X, Zheng L, Yang G, Liu T. Producing high value unsaturated fatty acid by whole-cell catalysis using microalga: A case study with Tribonema minus. Biotechnol Bioeng 2022; 119:2482-2493. [PMID: 35680651 DOI: 10.1002/bit.28157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 05/26/2022] [Accepted: 06/08/2022] [Indexed: 11/07/2022]
Abstract
High value unsaturated fatty acids can be produced by de novo synthesis in microalgal cells, especially via heterotrophic cultivation. Unfortunately, the lipid accumulation of heterotrophic microalgae cannot be improved efficiently in conventional ways. Here we reported heterotrophic Tribonema minus, a promising resource for the production of palmitoleic acid which has increasing demands in health service for patients with metabolic syndrome, as whole-cell biocatalyst to develop a novel way of shifting low value exogenous saturated fatty acids to high value ones. Results showed that myristic acid is the best precursor for whole-cell catalysis; it elevated the lipid content of T. minus to 42.2%, the highest among the tried precursors. The influences of cultivation condition on the utilization of extrinsic myristic acid and lipid accumulation were also determined. Under the optimized condition, the lipid content reached as high as 48.9%. In addition, our findings showed that ~13.0% of C16:1 in T. minus is derived from extrinsic myristic acid, and 30.1% of metabolized precursor is converted into heterologous fatty acids. Thus, a feasible approach for both increasing the value of low value saturated fatty acid by bioconversion and enhancing the lipid accumulation in microalgae is proposed by supplementing extrinsic myristic acid.
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Affiliation(s)
- Wenjun Zhou
- Microalgae Biotechnology Group, Key Laboratory of Biofuels, Key Laboratory of Shandong Province, Qingdao New Energy Shandong Laboratory, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,Bioenergy Division, Shandong Energy Institute, Qingdao, China
| | - Xiaotong Ji
- Microalgae Biotechnology Group, Key Laboratory of Biofuels, Key Laboratory of Shandong Province, Qingdao New Energy Shandong Laboratory, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,Bioenergy Division, Shandong Energy Institute, Qingdao, China.,School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Li Zheng
- Key Laboratory of Marine Eco-Environmental Science and Technology, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, China.,Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
| | - Guanpin Yang
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Tianzhong Liu
- Microalgae Biotechnology Group, Key Laboratory of Biofuels, Key Laboratory of Shandong Province, Qingdao New Energy Shandong Laboratory, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,Bioenergy Division, Shandong Energy Institute, Qingdao, China
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19
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Nam JW, Lee HG, Do H, Kim HU, Seo PJ. Transcriptional regulation of triacylglycerol accumulation in plants under environmental stress conditions. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:2905-2917. [PMID: 35560201 DOI: 10.1093/jxb/erab554] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 12/15/2021] [Indexed: 06/15/2023]
Abstract
Triacylglycerol (TAG), a major energy reserve in lipid form, accumulates mainly in seeds. Although TAG concentrations are usually low in vegetative tissues because of the repression of seed maturation programs, these programs are derepressed upon the exposure of vegetative tissues to environmental stresses. Metabolic reprogramming of TAG accumulation is driven primarily by transcriptional regulation. A substantial proportion of transcription factors regulating seed TAG biosynthesis also participates in stress-induced TAG accumulation in vegetative tissues. TAG accumulation leads to the formation of lipid droplets and plastoglobules, which play important roles in plant tolerance to environmental stresses. Toxic lipid intermediates generated from environmental-stress-induced lipid membrane degradation are captured by TAG-containing lipid droplets and plastoglobules. This review summarizes recent advances in the transcriptional control of metabolic reprogramming underlying stress-induced TAG accumulation, and provides biological insight into the plant adaptive strategy, linking TAG biosynthesis with plant survival.
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Affiliation(s)
- Jeong-Won Nam
- Department of Chemistry, Seoul National University, Seoul, South Korea
| | - Hong Gil Lee
- Plant Genomics and Breeding Institute, Seoul National University, Seoul, South Korea
| | - Hyungju Do
- Department of Bioindustry and Bioresource Engineering, Plant Engineering Research Institute, Sejong University, Seoul, South Korea
| | - Hyun Uk Kim
- Department of Bioindustry and Bioresource Engineering, Plant Engineering Research Institute, Sejong University, Seoul, South Korea
| | - Pil Joon Seo
- Department of Chemistry, Seoul National University, Seoul, South Korea
- Plant Genomics and Breeding Institute, Seoul National University, Seoul, South Korea
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20
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Cultivation of Microalgae in Unsterile Malting Effluent for Biomass Production and Lipid Productivity Improvement. FERMENTATION 2022. [DOI: 10.3390/fermentation8040186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Microalgae have the potential to grow in nutrient-rich environments and have the ability to accumulate nutrients from wastewater. The nutrients in malting wastewater are ideal for microalgae cultivation. However, there is limited published work on the growth characteristics of freshwater microalgae grown in malting effluent. This study examined the potential of diluted malting effluent for the growth of freshwater green algae Chlorella sp. and Chlamydomonas sp. isolated from northern Ontario and subsequent biomass and lipid production. Under the 18:6 h light/dark cultivation cycle, the highest cell number counted (540 × 104 cell·mL−1 on day 20) and total chlorophyll content were found in 50% diluted malting effluents for Chlorella sp., whereas the 70% dilution concentration was the most productive for Chlamydomonas (386 × 104 cell·mL−1 on day 16). The total lipid content was higher in the 50% dilution concentration of malting effluent in both Chlorella sp. (maximum 20.5%–minimum 11.5% of dry weight) and Chlamydomonas sp. (max 39.3%–min 25.9% of dry weight). These results emphasize the suitability of using unsterile diluted malting effluent for microalgae cultivation.
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21
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Reza AM, Rakhi SF, Zhu X, Tang Y, Qin J. Visualising the Emerging Platform of Using Microalgae as a Sustainable Bio-Factory for Healthy Lipid Production through Biocompatible AIE Probes. BIOSENSORS 2022; 12:bios12040208. [PMID: 35448268 PMCID: PMC9029145 DOI: 10.3390/bios12040208] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 03/27/2022] [Accepted: 03/29/2022] [Indexed: 11/16/2022]
Abstract
Nowadays, a particular focus is using microalgae to get high-valued health beneficiary lipids. The precise localisation of the lipid droplets (LDs) and biochemical changes are crucial to portray the lipid production strategy in algae, but it requires an in vivo tool to rapidly visualise LD distribution. As a novel strategy, this study focuses on detecting lipid bioaccumulation in a green microalga, Chlamydomonas reinhardtii using the aggregation-induced emission (AIE) based probe, 2-DPAN (C24H18N2O). As the messenger molecule and stress biomarker, hydrogen peroxide (H2O2) activity was detected in lipid synthesis with the AIE probe, TPE-BO (C38H42B2O4). Distinctive LDs labelled with 2-DPAN have elucidated the lipid inducing conditions, where more health beneficiary α-linolenic acid has been produced. TPE-BO labelled H2O2 have clarified the involvement of H2O2 during lipid biogenesis. The co-staining procedure with traditional green BODIPY dye and red chlorophyll indicates that 2-DPAN is suitable for multicolour LD imaging. Compared with BODIPY, 2-DPAN was an efficient sample preparation technique without the washing procedure. Thus, 2-DPAN could improve traditional fluorescent probes currently used for lipid imaging. In addition, the rapid, wash-free, multicolour AIE-based in vivo probe in the study of LDs with 2-DPAN could advance the research of lipid production in microalgae.
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Affiliation(s)
- Ahm Mohsinul Reza
- College of Science and Engineering, Flinders University, Adelaide, SA 5001, Australia
- Institute for NanoScale Science and Technology, College of Science and Engineering, Flinders University, Adelaide, SA 5001, Australia
| | - Sharmin Ferdewsi Rakhi
- College of Science and Engineering, Flinders University, Adelaide, SA 5001, Australia
- Institute for NanoScale Science and Technology, College of Science and Engineering, Flinders University, Adelaide, SA 5001, Australia
| | - Xiaochen Zhu
- College of Science and Engineering, Flinders University, Adelaide, SA 5001, Australia
- Institute for NanoScale Science and Technology, College of Science and Engineering, Flinders University, Adelaide, SA 5001, Australia
| | - Youhong Tang
- College of Science and Engineering, Flinders University, Adelaide, SA 5001, Australia
- Institute for NanoScale Science and Technology, College of Science and Engineering, Flinders University, Adelaide, SA 5001, Australia
| | - Jianguang Qin
- College of Science and Engineering, Flinders University, Adelaide, SA 5001, Australia
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22
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Zhang P, Xin Y, He Y, Tang X, Shen C, Wang Q, Lv N, Li Y, Hu Q, Xu J. Exploring a blue-light-sensing transcription factor to double the peak productivity of oil in Nannochloropsis oceanica. Nat Commun 2022; 13:1664. [PMID: 35351909 PMCID: PMC8964759 DOI: 10.1038/s41467-022-29337-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Accepted: 03/08/2022] [Indexed: 12/19/2022] Open
Abstract
Oleaginous microalgae can produce triacylglycerol (TAG) under stress, yet the underlying mechanism remains largely unknown. Here, we show that, in Nannochloropsis oceanica, a bZIP-family regulator NobZIP77 represses the transcription of a type-2 diacylgycerol acyltransferase encoding gene NoDGAT2B under nitrogen-repletion (N+), while nitrogen-depletion (N−) relieves such inhibition and activates NoDGAT2B expression and synthesis of TAG preferably from C16:1. Intriguingly, NobZIP77 is a sensor of blue light (BL), which reduces binding of NobZIP77 to the NoDGAT2B-promoter, unleashes NoDGAT2B and elevates TAG under N−. Under N+ and white light, NobZIP77 knockout fully preserves cell growth rate and nearly triples TAG productivity. Moreover, exposing the NobZIP77-knockout line to BL under N− can double the peak productivity of TAG. These results underscore the potential of coupling light quality to oil synthesis in feedstock or bioprocess development. Microalgae are promising feedstock for oil production. The authors report that a transcription factor NobZIP77 can regulate oil synthesis by sensing the blue light, and explore these findings to greatly enhance oil productivity via genetic and process engineering in Nannochloropsis oceanica.
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Autophagy Improves ARA-Rich TAG Accumulation in Mortierella alpina by Regulating Resource Allocation. Microbiol Spectr 2022; 10:e0130021. [PMID: 35138146 PMCID: PMC8881083 DOI: 10.1128/spectrum.01300-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The present study was designed to explore the possibility of improving lipid production in oleaginous filamentous fungus Mortierella alpina based on an autophagy regulation strategy. According to multiomics information, vacuolate-centered macroautophagy was identified as the main type of autophagy in M. alpina under nitrogen-limited conditions. Mutation of autophagy-related gene MAatg8 led to impaired fatty acid synthesis, while overexpression of both MAatg8 and phosphatidylserine decarboxylases (MApsd2) showed promoting effects on fatty acid synthesis. MAatg8 overexpression strain with external supply of ethanolamine significantly increased arachidonic acid (ARA)-rich triacylglycerol (TAG) and biomass synthesis in M. alpina, and the final fatty acid content increased by approximately 110% compared with that in the wild-type strain. Metabolomics and lipidomics analyses revealed that cell autophagy enhanced the recycling of preformed carbon, nitrogen, and lipid in mycelium, and the released carbon skeleton and energy were contributed to the accumulation of TAG in M. alpina. This study suggests that regulation of autophagy-related MAatg8-phosphatidylethanolamine (MAatg8-PE) conjugation system could be a promising strategy for attaining higher lipid production and biomass growth. The mechanism of autophagy in regulating nitrogen limitation-induced lipid accumulation elucidated in this study provides a reference for development of autophagy-based strategies for improving nutrient use efficiency and high value-added lipid production by oleaginous microorganism. IMPORTANCE Studies have indicated that functional oil accumulation occurs in oleaginous microorganisms under nitrogen limitation. However, until now, large-scale application of nitrogen-deficiency strategies was limited by low biomass. Therefore, the identification of the critical nodes of nitrogen deficiency-induced lipid accumulation is urgently needed to further guide functional oil production. The significance of our research is in uncovering the function of cell autophagy in the ARA-rich TAG accumulation of oleaginous fungus M. alpina and demonstrating the feasibility of improving lipid production based on an autophagy regulation strategy at the molecular and omics levels. Our study proves that regulation of cell autophagy through the MAatg8-PE conjugation system-related gene overexpression or exogenous supply of ethanolamine would be an efficient strategy to increase and maintain biomass productivity when high TAG content is obtained under nitrogen deficiency, which could be useful for the development of new strategies that will achieve more biomass and maximal lipid productivity.
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Santin A, Russo MT, Ferrante MI, Balzano S, Orefice I, Sardo A. Highly Valuable Polyunsaturated Fatty Acids from Microalgae: Strategies to Improve Their Yields and Their Potential Exploitation in Aquaculture. Molecules 2021; 26:7697. [PMID: 34946780 PMCID: PMC8707597 DOI: 10.3390/molecules26247697] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 11/16/2022] Open
Abstract
Microalgae have a great potential for the production of healthy food and feed supplements. Their ability to convert carbon into high-value compounds and to be cultured in large scale without interfering with crop cultivation makes these photosynthetic microorganisms promising for the sustainable production of lipids. In particular, microalgae represent an alternative source of polyunsaturated fatty acids (PUFAs), whose consumption is related to various health benefits for humans and animals. In recent years, several strategies to improve PUFAs' production in microalgae have been investigated. Such strategies include selecting the best performing species and strains and the optimization of culturing conditions, with special emphasis on the different cultivation systems and the effect of different abiotic factors on PUFAs' accumulation in microalgae. Moreover, developments and results obtained through the most modern genetic and metabolic engineering techniques are described, focusing on the strategies that lead to an increased lipid production or an altered PUFAs' profile. Additionally, we provide an overview of biotechnological applications of PUFAs derived from microalgae as safe and sustainable organisms, such as aquafeed and food ingredients, and of the main techniques (and their related issues) for PUFAs' extraction and purification from microalgal biomass.
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Affiliation(s)
- Anna Santin
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
| | - Monia Teresa Russo
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
| | - Maria Immacolata Ferrante
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
| | - Sergio Balzano
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
- Department of Marine Microbiology and Biogeochemistry, Netherland Institute for Sea Research, Landsdiep 4, 1793 AB Texel, The Netherlands
| | - Ida Orefice
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
| | - Angela Sardo
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
- Istituto di Scienze Applicate e Sistemi Intelligenti “Eduardo Caianiello”, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
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Naduthodi MIS, Südfeld C, Avitzigiannis EK, Trevisan N, van Lith E, Alcaide Sancho J, D’Adamo S, Barbosa M, van der Oost J. Comprehensive Genome Engineering Toolbox for Microalgae Nannochloropsis oceanica Based on CRISPR-Cas Systems. ACS Synth Biol 2021; 10:3369-3378. [PMID: 34793143 PMCID: PMC8689688 DOI: 10.1021/acssynbio.1c00329] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Microalgae can produce
industrially relevant metabolites using
atmospheric CO2 and sunlight as carbon and energy sources,
respectively. Developing molecular tools for high-throughput genome
engineering could accelerate the generation of tailored strains with
improved traits. To this end, we developed a genome editing strategy
based on Cas12a ribonucleoproteins (RNPs) and homology-directed repair
(HDR) to generate scarless and markerless mutants of the microalga Nannochloropsis oceanica. We also developed an episomal
plasmid-based Cas12a system for efficiently introducing indels at
the target site. Additionally, we exploited the ability of Cas12a
to process an associated CRISPR array to perform multiplexed genome
engineering. We efficiently targeted three sites in the host genome
in a single transformation, thereby making a major step toward high-throughput
genome engineering in microalgae. Furthermore, a CRISPR interference
(CRISPRi) tool based on Cas9 and Cas12a was developed for effective
downregulation of target genes. We observed up to 85% reduction in
the transcript levels upon performing CRISPRi with dCas9 in N. oceanica. Overall, these developments substantially
accelerate genome engineering efforts in N. oceanica and potentially provide a general toolbox for improving other microalgal
strains.
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Affiliation(s)
- Mihris Ibnu Saleem Naduthodi
- Laboratory of Microbiology, Wageningen University, Wageningen 6708 WE, The Netherlands
- Bioprocess Engineering, Wageningen University, Wageningen 6708 PB, The Netherlands
| | - Christian Südfeld
- Bioprocess Engineering, Wageningen University, Wageningen 6708 PB, The Netherlands
| | | | - Nicola Trevisan
- Bioprocess Engineering, Wageningen University, Wageningen 6708 PB, The Netherlands
| | - Eduard van Lith
- Laboratory of Microbiology, Wageningen University, Wageningen 6708 WE, The Netherlands
| | - Javier Alcaide Sancho
- Laboratory of Microbiology, Wageningen University, Wageningen 6708 WE, The Netherlands
| | - Sarah D’Adamo
- Bioprocess Engineering, Wageningen University, Wageningen 6708 PB, The Netherlands
| | - Maria Barbosa
- Bioprocess Engineering, Wageningen University, Wageningen 6708 PB, The Netherlands
| | - John van der Oost
- Laboratory of Microbiology, Wageningen University, Wageningen 6708 WE, The Netherlands
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26
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Beneficial use of the aqueous phase generated during hydrothermal carbonization of algae as nutrient source for algae cultivation. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102485] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Bai F, Zhang Y, Liu J. A bZIP transcription factor is involved in regulating lipid and pigment metabolisms in the green alga Chlamydomonas reinhardtii. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102450] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Feasibility of the Hybrid Use of Chlorella vulgaris Culture with the Conventional Biological Treatment in Urban Wastewater Treatment Plants. Processes (Basel) 2021. [DOI: 10.3390/pr9091640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Currently, most wastewater treatment plants do not meet the legal requirements, especially regarding phosphorus and nitrogen contents. In this work, real primary urban wastewater (P-UW) was used as culture medium for the growth of Chlorella vulgaris. Experiments were carried out in batch photobioreactors at laboratory scale. To determine the maximum nutrient removal levels and the optimal pH value for C. vulgaris growth, the following pH values were studied: 5, 6, 7, 8, 9, 10, and 11. Additionally, two control experiments were conducted using UW and tap water at the same conditions but without microalgae inoculation. The operational conditions were agitation rate = 200 rpm, T = 25 °C, aeration rate = 0.5 L/min, and continuous light with illumination intensity = 359 µE m−2 s−1. Significant higher growth was obtained at pH = 7. The direct use of C. vulgaris for P-UW treatment demonstrated high removal percentages of organic (COD and BOD5 removal = 63.4% and 92.3%, respectively) and inorganic compounds (inorganic carbon removal = 99.6%). The final biomass was characterized by an accumulation of high energetic compounds, mainly carbohydrates, which ranged between 63.3% (pH = 5) and 82.8% (pH = 11) and represent a source of biofuels. These new achievements open up the possibility of new horizons in urban wastewater treatment.
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Reza AHMM, Zhou Y, Qin J, Tang Y. Aggregation-induced emission luminogens for lipid droplet imaging. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2021; 184:101-144. [PMID: 34749970 DOI: 10.1016/bs.pmbts.2021.06.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Lipid droplets (LDs) are evolutionarily conserved organelles involved in energy homeostasis and versatile intracellular processes in different cell types. Their importance is ubiquitous, ranges from utilization as the biofunctional components to third-generation biofuel production from microalgae, while morphology and functional perturbations could also relate to the multiple diseases in higher mammals. Biosynthesis of lipids can be triggered by multiple factors related to organismal physiology and the surrounding environment. An early prediction of this might help take necessary actions toward desired outcomes. In vivo visualization of LDs can give molecular insight into regulatory mechanisms and the underlying connections with other cellular structures. Traditional bioprobes for LDs detection often suffer from different dye-specific limitations such as aggregation-caused quenching and self-decomposition phenomena that hinder the research advancement. The emergence of lipid-specific nanoprobes with aggregation-induced emission (AIE) attributes in recent years is promising in remunerative characteristics with defined bioimaging properties. By utilizing the easy synthetic techniques and exploiting the unique physical features of these molecules, highly selective, stable, biocompatible and facile fluorescent probes could be fabricated for lipid detection. This chapter will provide up-to-date insight into the recent advances in lipid-specific AIE-based probes to enhance the opportunities for basic research related to the distinct roles of LDs in living organisms.
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Affiliation(s)
- A H M Mohsinul Reza
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia; Institute for NanoScale Science and Technology, College of Science and Engineering, Flinders University, Adelaide, SA, Australia
| | - Yabin Zhou
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia
| | - Jianguang Qin
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia.
| | - Youhong Tang
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia; Institute for NanoScale Science and Technology, College of Science and Engineering, Flinders University, Adelaide, SA, Australia.
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Fatty Acid Production and Direct Acyl Transfer through Polar Lipids Control TAG Biosynthesis during Nitrogen Deprivation in the Halotolerant Alga Dunaliella tertiolecta. Mar Drugs 2021; 19:md19070368. [PMID: 34202376 PMCID: PMC8304655 DOI: 10.3390/md19070368] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/10/2021] [Accepted: 06/23/2021] [Indexed: 12/31/2022] Open
Abstract
The aims of this work were to evaluate the contribution of the free fatty acid (FA) pool to triacylglyceride (TAG) biosynthesis and to try to characterize the mechanism by which FA are assimilated into TAG in the green alga Dunaliella tertiolecta. A time-resolved lipidomic analysis showed that nitrogen (N) deprivation induces a redistribution of total lipidome, particularly of free FA and major polar lipid (PL), in parallel to enhanced accumulation of polyunsaturated TAG. The steady-state concentration of the FA pool, measured by prolonged 14C-bicarbonate pre-labeling, showed that N deprivation induced a 50% decrease in total FA level within the first 24 h and up to 85% after 96 h. The abundance of oleic acid increased from 50 to 70% of total free FA while polyunsaturated FA (PUFA) disappeared under N deprivation. The FA flux, measured by the rate of incorporation of 14C-palmitic acid (PlA), suggests partial suppression of phosphatidylcholine (PC) acyl editing and an enhanced turnover of the FA pool and of total digalactosyl-diacylglycerol (DGDG) during N deprivation. Taken together, these results imply that FA biosynthesis is a major rate-controlling stage in TAG biosynthesis in D. tertiolecta and that acyl transfer through PL such as PC and DGDG is the major FA assimilation pathway into TAG in that alga and possibly in other green microalgae. Increasing the availability of FA could lead to enhanced TAG biosynthesis and to improved production of high-value products from microalgae.
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Chen H, Wang Q. Regulatory mechanisms of lipid biosynthesis in microalgae. Biol Rev Camb Philos Soc 2021; 96:2373-2391. [PMID: 34101323 DOI: 10.1111/brv.12759] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 05/26/2021] [Accepted: 05/27/2021] [Indexed: 02/01/2023]
Abstract
Microalgal lipids are highly promising feedstocks for biofuel production. Microalgal lipids, especially triacylglycerol, and practical applications of these compounds have received increasing attention in recent years. For the commercial use of microalgal lipids to be feasible, many fundamental biological questions must be addressed based on detailed studies of algal biology, including how lipid biosynthesis occurs and is regulated. Here, we review the current understanding of microalgal lipid biosynthesis, with a focus on the underlying regulatory mechanisms. We also present possible solutions for overcoming various obstacles to understanding the basic biology of microalgal lipid biosynthesis and the practical application of microalgae-based lipids. This review will provide a theoretical reference for both algal researchers and decision makers regarding the future directions of microalgal research, particularly pertaining to microalgal-based lipid biosynthesis.
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Affiliation(s)
- Hui Chen
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Qiang Wang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
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Hounslow E, Evans CA, Pandhal J, Sydney T, Couto N, Pham TK, Gilmour DJ, Wright PC. Quantitative proteomic comparison of salt stress in Chlamydomonas reinhardtii and the snow alga Chlamydomonas nivalis reveals mechanisms for salt-triggered fatty acid accumulation via reallocation of carbon resources. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:121. [PMID: 34022944 PMCID: PMC8141184 DOI: 10.1186/s13068-021-01970-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 05/13/2021] [Indexed: 06/01/2023]
Abstract
BACKGROUND Chlamydomonas reinhardtii is a model green alga strain for molecular studies; its fully sequenced genome has enabled omic-based analyses that have been applied to better understand its metabolic responses to stress. Here, we characterised physiological and proteomic changes between a low-starch C. reinhardtii strain and the snow alga Chlamydomonas nivalis, to reveal insights into their contrasting responses to salinity stress. RESULTS Each strain was grown in conditions tailored to their growth requirements to encourage maximal fatty acid (as a proxy measure of lipid) production, with internal controls to allow comparison points. In 0.2 M NaCl, C. nivalis accumulates carbohydrates up to 10.4% DCW at 80 h, and fatty acids up to 52.0% dry cell weight (DCW) over 12 days, however, C. reinhardtii does not show fatty acid accumulation over time, and shows limited carbohydrate accumulation up to 5.5% DCW. Analysis of the C. nivalis fatty acid profiles showed that salt stress improved the biofuel qualities over time. Photosynthesis and respiration rates are reduced in C. reinhardtii relative to C. nivalis in response to 0.2 M NaCl. De novo sequencing and homology matching was used in conjunction with iTRAQ-based quantitative analysis to identify and relatively quantify proteomic alterations in cells exposed to salt stress. There were abundance differences in proteins associated with stress, photosynthesis, carbohydrate and lipid metabolism proteins. In terms of lipid synthesis, salt stress induced an increase in dihydrolipoyl dehydrogenase in C. nivalis (1.1-fold change), whilst levels in C. reinhardtii remained unaffected; this enzyme is involved in acetyl CoA production and has been linked to TAG accumulation in microalgae. In salt-stressed C. nivalis there were decreases in the abundance of UDP-sulfoquinovose (- 1.77-fold change), which is involved in sulfoquinovosyl diacylglycerol metabolism, and in citrate synthase (- 2.7-fold change), also involved in the TCA cycle. Decreases in these enzymes have been shown to lead to increased TAG production as fatty acid biosynthesis is favoured. Data are available via ProteomeXchange with identifier PXD018148. CONCLUSIONS These differences in protein abundance have given greater understanding of the mechanism by which salt stress promotes fatty acid accumulation in the un-sequenced microalga C. nivalis as it switches to a non-growth state, whereas C. reinhardtii does not have this response.
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Affiliation(s)
- E Hounslow
- Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK
| | - C A Evans
- Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK.
| | - J Pandhal
- Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK
| | - T Sydney
- Department of Chemistry, University of Sheffield, Sheffield, S3 7HF, UK
| | - N Couto
- Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK
| | - T K Pham
- Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK
| | - D James Gilmour
- Department of Molecular Biology and Biotechnology, Firth Court, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - P C Wright
- University of Southampton, University Road, Southampton, SO17 1BJ, UK
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Guéguen N, Le Moigne D, Amato A, Salvaing J, Maréchal E. Lipid Droplets in Unicellular Photosynthetic Stramenopiles. FRONTIERS IN PLANT SCIENCE 2021; 12:639276. [PMID: 33968100 PMCID: PMC8100218 DOI: 10.3389/fpls.2021.639276] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
The Heterokonta or Stramenopile phylum comprises clades of unicellular photosynthetic species, which are promising for a broad range of biotechnological applications, based on their capacity to capture atmospheric CO2 via photosynthesis and produce biomolecules of interest. These molecules include triacylglycerol (TAG) loaded inside specific cytosolic bodies, called the lipid droplets (LDs). Understanding TAG production and LD biogenesis and function in photosynthetic stramenopiles is therefore essential, and is mostly based on the study of a few emerging models, such as the pennate diatom Phaeodactylum tricornutum and eustigmatophytes, such as Nannochloropsis and Microchloropsis species. The biogenesis of cytosolic LD usually occurs at the level of the endoplasmic reticulum. However, stramenopile cells contain a complex plastid deriving from a secondary endosymbiosis, limited by four membranes, the outermost one being connected to the endomembrane system. Recent cell imaging and proteomic studies suggest that at least some cytosolic LDs might be associated to the surface of the complex plastid, via still uncharacterized contact sites. The carbon length and number of double bonds of the acyl groups contained in the TAG molecules depend on their origin. De novo synthesis produces long-chain saturated or monounsaturated fatty acids (SFA, MUFA), whereas subsequent maturation processes lead to very long-chain polyunsaturated FA (VLC-PUFA). TAG composition in SFA, MUFA, and VLC-PUFA reflects therefore the metabolic context that gave rise to the formation of the LD, either via an early partitioning of carbon following FA de novo synthesis and/or a recycling of FA from membrane lipids, e.g., plastid galactolipids or endomembrane phosphor- or betaine lipids. In this review, we address the relationship between cytosolic LDs and the complex membrane compartmentalization within stramenopile cells, the metabolic routes leading to TAG accumulation, and the physiological conditions that trigger LD production, in response to various environmental factors.
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Enhancing carbohydrate repartitioning into lipid and carotenoid by disruption of microalgae starch debranching enzyme. Commun Biol 2021; 4:450. [PMID: 33837247 PMCID: PMC8035404 DOI: 10.1038/s42003-021-01976-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 03/11/2021] [Indexed: 02/01/2023] Open
Abstract
Light/dark cycling is an inherent condition of outdoor microalgae cultivation, but is often unfavorable for lipid accumulation. This study aims to identify promising targets for metabolic engineering of improved lipid accumulation under outdoor conditions. Consequently, the lipid-rich mutant Chlamydomonas sp. KOR1 was developed through light/dark-conditioned screening. During dark periods with depressed CO2 fixation, KOR1 shows rapid carbohydrate degradation together with increased lipid and carotenoid contents. KOR1 was subsequently characterized with extensive mutation of the ISA1 gene encoding a starch debranching enzyme (DBE). Dynamic time-course profiling and metabolomics reveal dramatic changes in KOR1 metabolism throughout light/dark cycles. During light periods, increased flux from CO2 through glycolytic intermediates is directly observed to accompany enhanced formation of small starch-like particles, which are then efficiently repartitioned in the next dark cycle. This study demonstrates that disruption of DBE can improve biofuel production under light/dark conditions, through accelerated carbohydrate repartitioning into lipid and carotenoid.
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Mixotrophic cultivation of Thalassiosira pseudonana with pure and crude glycerol: Impact on lipid profile. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102194] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Yu C, Li X, Han B, Zhao Y, Geng S, Ning D, Ma T, Yu X. Simultaneous improvement of astaxanthin and lipid production of Haematococcus pluvialis by using walnut shell extracts. ALGAL RES 2021. [DOI: 10.1016/j.algal.2020.102171] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Isolation of Industrial Important Bioactive Compounds from Microalgae. Molecules 2021; 26:molecules26040943. [PMID: 33579001 PMCID: PMC7916812 DOI: 10.3390/molecules26040943] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/24/2020] [Accepted: 01/05/2021] [Indexed: 12/24/2022] Open
Abstract
Microalgae are known as a rich source of bioactive compounds which exhibit different biological activities. Increased demand for sustainable biomass for production of important bioactive components with various potential especially therapeutic applications has resulted in noticeable interest in algae. Utilisation of microalgae in multiple scopes has been growing in various industries ranging from harnessing renewable energy to exploitation of high-value products. The focuses of this review are on production and the use of value-added components obtained from microalgae with current and potential application in the pharmaceutical, nutraceutical, cosmeceutical, energy and agri-food industries, as well as for bioremediation. Moreover, this work discusses the advantage, potential new beneficial strains, applications, limitations, research gaps and future prospect of microalgae in industry.
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Resemann HC, Herrfurth C, Feussner K, Hornung E, Ostendorf AK, Gömann J, Mittag J, van Gessel N, Vries JD, Ludwig-Müller J, Markham J, Reski R, Feussner I. Convergence of sphingolipid desaturation across over 500 million years of plant evolution. NATURE PLANTS 2021; 7:219-232. [PMID: 33495556 DOI: 10.1038/s41477-020-00844-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 12/18/2020] [Indexed: 05/16/2023]
Abstract
For plants, acclimation to low temperatures is fundamental to survival. This process involves the modification of lipids to maintain membrane fluidity. We previously identified a new cold-induced putative desaturase in Physcomitrium (Physcomitrella) patens. Lipid profiles of null mutants of this gene lack sphingolipids containing monounsaturated C24 fatty acids, classifying the new protein as sphingolipid fatty acid denaturase (PpSFD). PpSFD mutants showed a cold-sensitive phenotype as well as higher susceptibility to the oomycete Pythium, assigning functions in stress tolerance for PpSFD. Ectopic expression of PpSFD in the Atads2.1 (acyl coenzyme A desaturase-like 2) Arabidopsis thaliana mutant functionally complemented its cold-sensitive phenotype. While these two enzymes catalyse a similar reaction, their evolutionary origin is clearly different since AtADS2 is a methyl-end desaturase whereas PpSFD is a cytochrome b5 fusion desaturase. Altogether, we suggest that adjustment of membrane fluidity evolved independently in mosses and seed plants, which diverged more than 500 million years ago.
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Affiliation(s)
- Hanno Christoph Resemann
- Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, Goettingen, Germany
| | - Cornelia Herrfurth
- Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, Goettingen, Germany
- Goettingen Metabolomics and Lipidomics Laboratory, Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany
| | - Kirstin Feussner
- Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, Goettingen, Germany
- Goettingen Metabolomics and Lipidomics Laboratory, Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany
| | - Ellen Hornung
- Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, Goettingen, Germany
| | - Anna K Ostendorf
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Jasmin Gömann
- Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, Goettingen, Germany
| | - Jennifer Mittag
- Institute of Botany, Technical University Dresden, Dresden, Germany
| | - Nico van Gessel
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Jan de Vries
- Applied Bioinformatics, Institute for Microbiology and Genetics, University of Goettingen, Goettingen, Germany
- Applied Bioinformatics, Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany
- Campus Institute Data Science (CIDAS), University of Goettingen, Goettingen, Germany
| | | | - Jennifer Markham
- Center for Plant Science Innovation and Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Ralf Reski
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany.
- Signalling Research Centers BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.
| | - Ivo Feussner
- Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, Goettingen, Germany.
- Goettingen Metabolomics and Lipidomics Laboratory, Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany.
- Plant Biochemistry, Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany.
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Cui H, Zhao C, Xu W, Zhang H, Hang W, Zhu X, Ji C, Xue J, Zhang C, Li R. Characterization of type-2 diacylglycerol acyltransferases in Haematococcus lacustris reveals their functions and engineering potential in triacylglycerol biosynthesis. BMC PLANT BIOLOGY 2021; 21:20. [PMID: 33407140 PMCID: PMC7788937 DOI: 10.1186/s12870-020-02794-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 12/09/2020] [Indexed: 05/05/2023]
Abstract
BACKGROUND Haematococcus lacustris is an ideal source of astaxanthin (AST), which is stored in oil bodies containing esterified AST (EAST) and triacylglycerol (TAG). Diacylglycerol acyltransferases (DGATs) catalyze the last step of acyl-CoA-dependent TAG biosynthesis and are also considered as crucial enzymes involved in EAST biosynthesis in H. lacustris. Previous studies have identified four putative DGAT2-encoding genes in H. lacustris, and only HpDGAT2D allowed the recovery of TAG biosynthesis, but the engineering potential of HpDGAT2s in TAG biosynthesis remains ambiguous. RESULTS Five putative DGAT2 genes (HpDGAT2A, HpDGAT2B, HpDGAT2C, HpDGAT2D, and HpDGAT2E) were identified in H. lacustris. Transcription analysis showed that the expression levels of the HpDGAT2A, HpDGAT2D, and HpDGAT2E genes markedly increased under high light and nitrogen deficient conditions with distinct patterns, which led to significant TAG and EAST accumulation. Functional complementation demonstrated that HpDGAT2A, HpDGAT2B, HpDGAT2D, and HpDGAT2E had the capacity to restore TAG synthesis in a TAG-deficient yeast strain (H1246) showing a large difference in enzymatic activity. Fatty acid (FA) profile assays revealed that HpDGAT2A, HpDGAT2D, and HpDGAT2E, but not HpDGAT2B, preferred monounsaturated fatty acyl-CoAs (MUFAs) for TAG synthesis in yeast cells, and showed a preference for polyunsaturated fatty acyl-CoAs (PUFAs) based on their feeding strategy. The heterologous expression of HpDGAT2D in Arabidopsis thaliana and Chlamydomonas reinhardtii significantly increased the TAG content and obviously promoted the MUFAs and PUFAs contents. CONCLUSIONS Our study represents systematic work on the characterization of HpDGAT2s by integrating expression patterns, AST/TAG accumulation, functional complementation, and heterologous expression in yeast, plants, and algae. These results (1) update the gene models of HpDGAT2s, (2) prove the TAG biosynthesis capacity of HpDGAT2s, (3) show the strong preference for MUFAs and PUFAs, and (4) offer target genes to modulate TAG biosynthesis by using genetic engineering methods.
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Affiliation(s)
- Hongli Cui
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Chunchao Zhao
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Wenxin Xu
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Hongjiang Zhang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Wei Hang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Xiaoli Zhu
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Chunli Ji
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Jinai Xue
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Chunhui Zhang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Runzhi Li
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
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Cui H, Xu W, Zhu X, Zhao C, Cui Y, Ji C, Zhang C, Xue J, Qin S, Jia X, Li R. Characterization of a Haematococcus pluvialis Diacylglycerol Acyltransferase 1 and Its Potential in Unsaturated Fatty Acid-Rich Triacylglycerol Production. FRONTIERS IN PLANT SCIENCE 2021; 12:771300. [PMID: 34950166 PMCID: PMC8688921 DOI: 10.3389/fpls.2021.771300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 11/08/2021] [Indexed: 05/17/2023]
Abstract
The unicellular green alga Haematococcus pluvialis has been recognized as an industry strain to produce simultaneously esterified astaxanthin (EAST) and triacylglycerol (TAG) under stress induction. It is necessary to identify the key enzymes involving in synergistic accumulation of EAST and TAG in H. pluvialis. In this study, a novel diacylglycerol acyltransferase 1 was systematically characterized by in vivo and in silico assays. The upregulated expression of HpDGAT1 gene was positively associated with the significant increase of TAG and EAST contents under stress conditions. Functional complementation by overexpressing HpDGAT1 in a TAG-deficient yeast strain H1246 revealed that HpDGAT1 could restore TAG biosynthesis and exhibited a high substrate preference for monounsaturated fatty acyl-CoAs (MUFAs) and polyunsaturated fatty acyl-CoAs (PUFAs). Notably, heterogeneous expression of HpDGAT1 in Chlamydomonas reinhardtii and Arabidopsis thaliana resulted in a significant enhancement of total oils and concurrently a high accumulation of MUFAs- and PUFAs-rich TAGs. Furthermore, molecular docking analysis indicated that HpDGAT1 contained AST-binding sites. These findings evidence a possible dual-function role for HpDGAT1 involving in TAG and EAST synthesis, demonstrating that it is a potential target gene to enrich AST accumulation in this alga and to design oil production in both commercial algae and oil crops.
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Affiliation(s)
- Hongli Cui
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Wenxin Xu
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Xiaoli Zhu
- College of Plant Protection, Shanxi Agricultural University, Taigu, China
| | - Chunchao Zhao
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Yulin Cui
- Key Laboratory of Coastal Biology and Biological Resource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
| | - Chunli Ji
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Chunhui Zhang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Jinai Xue
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Song Qin
- Key Laboratory of Coastal Biology and Biological Resource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
| | - Xiaoyun Jia
- College of Life Sciences, Shanxi Agricultural University, Taigu, China
| | - Runzhi Li
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
- *Correspondence: Runzhi Li,
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Chungjatupornchai W, Fa-Aroonsawat S. Enhanced triacylglycerol production in oleaginous microalga Neochloris oleoabundans by co-overexpression of lipogenic genes: Plastidial LPAAT1 and ER-located DGAT2. J Biosci Bioeng 2020; 131:124-130. [PMID: 33069576 DOI: 10.1016/j.jbiosc.2020.09.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 09/18/2020] [Accepted: 09/18/2020] [Indexed: 12/29/2022]
Abstract
Microalgae accumulate lipid triacylglycerol (TAG), a promising feedstock for production of natural edible oils and biofuels. To make products derived from microalgal TAG economically viable, increasing TAG content and productivity are of high importance. To increase TAG content, two endogenous key enzymes of TAG biosynthesis: plastidial lysophosphatidic acid acyltransferase (NeoLPAAT1) and endoplasmic reticulum-located diacylglycerol acyltransferase 2 (NeoDGAT2) were co-overexpressed in oleaginous microalga Neochloris oleoabundans. The neutral lipid content in NeoLPAAT1-NeoDGAT2 co-overexpressing transformant detected by Nile red staining increased 2-fold without compromising cell growth. The transcriptional levels of NeoLPAAT1 and NeoDGAT2 levels were 1.9-fold higher in the transformant than wild type. Considerably higher lipid accumulation was found in the transformant than wild type: total lipid content (73.72 ± 4.17 % DCW) increased 1.6-fold, TAG content (50.63 ± 6.15 % DCW) increased 2.1-fold, total lipid productivity (16.84 ± 0.66 mg/L/day) increased 1.9-fold, and TAG productivity (11.68 ± 0.90 mg/L/day) increased 2.1-fold. Fatty acid composition was slightly altered in the transformant compared to wild type; saturated fatty acid C16:0 increased to 26% from 20%, whereas C18:0 was reduced to 7% from 14%. Long-term stability of NeoLPAAT1-NeoDGAT2 co-overexpression was observed in the transformant continuously maintained on solid medium in a period of 4 years. The results suggested that targeted engineering of genes in pathway located at different organelles should be possible in microalgal lipid metabolism.
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Affiliation(s)
- Wipa Chungjatupornchai
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakhon Pathom 73170, Thailand.
| | - Sirirat Fa-Aroonsawat
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakhon Pathom 73170, Thailand.
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42
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Bacova R, Kolackova M, Klejdus B, Adam V, Huska D. Epigenetic mechanisms leading to genetic flexibility during abiotic stress responses in microalgae: A review. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.101999] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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43
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Fu L, Yan G, Li Y, Li Q, Zhou D. Phosphorus supply via a fed-batch strategy improves lipid heterotrophic production of Chlorella regularis. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:31677-31685. [PMID: 32500492 DOI: 10.1007/s11356-020-09495-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 05/27/2020] [Indexed: 06/11/2023]
Abstract
Intracellular phosphorus (P) accumulation can improve microalgal growth and lipid synthesis. However, large excess of P causes cell poisoning. This study utilized a P-fed-batch strategy to investigate its potential to improve the utilization of the excessive P, while avoiding toxic side effects. This strategy contributed to a more complete utilization of the intracellularly stored P, which enhanced the microalgae biomass by 10-15% by upregulating the brassinosteroid growth hormone gene at a P-fed-batch frequency of 2-8. Furthermore, the lipid content increased by 4-16% via upregulation of lipid synthesis-related genes. As a result, the P-fed-batch strategy significantly increased the lipid production by 13-19%. The content of saturated fatty acid increased by ~ 100%, implying improved combustibility and oxidative stability. This is the first study of this P-fed-batch strategy and provides a new concept for the complete utilization of excessive P.
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Affiliation(s)
- Liang Fu
- Engineering Lab for Water Pollution Control and Resources Recovery, School of Environment, Northeast Normal University, Changchun, 130117, China
| | - Ge Yan
- Engineering Lab for Water Pollution Control and Resources Recovery, School of Environment, Northeast Normal University, Changchun, 130117, China
| | - Yunbao Li
- Key Laboratory of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun, 130021, China
| | - Qingcheng Li
- Engineering Lab for Water Pollution Control and Resources Recovery, School of Environment, Northeast Normal University, Changchun, 130117, China
| | - Dandan Zhou
- Engineering Lab for Water Pollution Control and Resources Recovery, School of Environment, Northeast Normal University, Changchun, 130117, China.
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44
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Yang H, Hu C. Regulation and remodeling of intermediate metabolite and membrane lipid during NaCl-induced stress in freshwater microalga Micractinium sp. XJ-2 for biofuel production. Biotechnol Bioeng 2020; 117:3727-3738. [PMID: 32749671 DOI: 10.1002/bit.27528] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/25/2020] [Accepted: 08/03/2020] [Indexed: 01/23/2023]
Abstract
Microalgae can accumulate a large fraction of reduced carbon as lipids under NaCl stress. This study investigated the mechanism of carbon allocation and reduction and triacylglycerol (TAG) accumulation in microalgae under NaCl-induced stress. Micractinium sp. XJ-2 was exposed to NaCl stress and cells were subjected to physiological, biochemical, and metabolic analyses to elucidate the stress-responsive mechanism. Lipid increased with NaCl concentration after 0-12 hr, then stabilized after 12-48 hr, and finally decreased after 48-72 hr, whereas TAG increased (0-48 hr) and then decreased (48-72 hr). Under NaCl-induced stress at lower concentrations, TAG accumulation, at first, mainly shown to rely on the carbon fixation through photosynthetic fixation, carbohydrate degradation, and membrane lipids remodeling. Moreover, carbon compounds generated by the degradation of some amino acids were reallocated and enhanced fatty acid synthesis. The remodeling of the membrane lipids of NaCl-induced microalgae relied on the following processes: (a) Increase in the amount of phospholipids and reduction in the amount of glycolipids and (b) extension of long-chain fatty acids. This study enhances our understanding of TAG production under NaCl stress and thus will provide a theoretical basis for the industrial application of NaCl-induced in the microalgal biodiesel industry.
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Affiliation(s)
- Haijian Yang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Chunxiang Hu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
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45
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Wood NJ, Baker A, Quinnell RJ, Camargo-Valero MA. A Simple and Non-destructive Method for Chlorophyll Quantification of Chlamydomonas Cultures Using Digital Image Analysis. Front Bioeng Biotechnol 2020; 8:746. [PMID: 32793564 PMCID: PMC7386287 DOI: 10.3389/fbioe.2020.00746] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 06/11/2020] [Indexed: 11/17/2022] Open
Abstract
Growing interest in the use of microalgae as a sustainable feedstock to support a green, circular, bio-economy has led to intensive research and development initiatives aimed at increasing algal biomass production covering a wide range of scales. At the heart of this lies a common need for rapid and accurate methods to measure algal biomass concentrations. Surrogate analytical techniques based on chlorophyll content use solvent extraction methods for chlorophyll quantification, but these methods are destructive, time consuming and require careful disposal of the resultant solvent waste. Alternative non-destructive methods based on chlorophyll fluorescence require expensive equipment and are less suitable for multiple sampling of small cultures which need to be maintained under axenic growth conditions. A simple, inexpensive and non-destructive method to estimate chlorophyll concentration of microalgal cultures in situ from digital photographs using the RGB color model is presented. Green pixel intensity and chlorophyll a, b and total chlorophyll concentration, measured by conventional means, follow a strong linear relationship (R2 = 0.985–0.988). In addition, the resulting standard curve was robust enough to accurately estimate chlorophyll concentration despite changes in sample volume, pH and low concentrations of bacterial contamination. In contrast, use of the same standard curve during nitrogen deprivation (causing the accumulation of neutral lipids) or in the presence of high quantities of bacterial contamination led to significant errors in chlorophyll estimation. The low requirement for equipment (i.e., a simple digital camera, available on smartphones) and widely available standard software for measuring pixel intensity make this method suitable for both laboratory and field-based work, particularly in situations where sample, qualified personnel and/or equipment is limited. By following the methods described here it should be possible to produce a standard curve for chlorophyll analysis in a wide range of testing conditions including different microalga cultures, culture vessel and photographic set up in any particular laboratory.
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Affiliation(s)
- Nicola J Wood
- Centre for Doctoral Training in Bioenergy, School of Chemical and Process Engineering, University of Leeds, Leeds, United Kingdom.,BioResource Systems Research Group, School of Civil Engineering, University of Leeds, Leeds, United Kingdom
| | - Alison Baker
- Centre for Plant Sciences and School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Rupert J Quinnell
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Miller Alonso Camargo-Valero
- BioResource Systems Research Group, School of Civil Engineering, University of Leeds, Leeds, United Kingdom.,Departamento de Ingeniería Química, Universidad Nacional de Colombia, Manizales, Colombia
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46
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Chan LG, Dias FFG, Saarni A, Cohen J, Block D, Taha AY, Moura Bell JMLN. Scaling up the Bioconversion of Cheese Whey Permeate into Fungal Oil by
Mucor circinelloides. J AM OIL CHEM SOC 2020. [DOI: 10.1002/aocs.12372] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Lauryn G. Chan
- Department of Food Science and TechnologyUniversity of California, Davis One Shields Avenue, Davis CA 95616 USA
| | - Fernanda F. G. Dias
- Department of Food Science and TechnologyUniversity of California, Davis One Shields Avenue, Davis CA 95616 USA
| | - Andrew Saarni
- Department of Chemical EngineeringUniversity of California, Davis One Shields Avenue, Davis CA 95616 USA
| | - Joshua Cohen
- Department of Food Science and TechnologyUniversity of California, Davis One Shields Avenue, Davis CA 95616 USA
| | - David Block
- Department of Chemical EngineeringUniversity of California, Davis One Shields Avenue, Davis CA 95616 USA
- Department of Viticulture and EnologyUniversity of California, Davis One Shields Avenue, Davis CA 95616 USA
| | - Ameer Y. Taha
- Department of Food Science and TechnologyUniversity of California, Davis One Shields Avenue, Davis CA 95616 USA
| | - Juliana M. L. N. Moura Bell
- Department of Food Science and TechnologyUniversity of California, Davis One Shields Avenue, Davis CA 95616 USA
- Department of Biological and Agricultural EngineeringUniversity of California, Davis One Shields Avenue, Davis CA 95616 USA
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Song C, Han X, Qiu Y, Liu Z, Li S, Kitamura Y. Microalgae carbon fixation integrated with organic matters recycling from soybean wastewater: Effect of pH on the performance of hybrid system. CHEMOSPHERE 2020; 248:126094. [PMID: 32041073 DOI: 10.1016/j.chemosphere.2020.126094] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 12/29/2019] [Accepted: 02/01/2020] [Indexed: 06/10/2023]
Abstract
Microalgae have been considered as promising alternative for CO2 fixation and wastewater purification. In our previous work, a hybrid microalgae CO2 fixation concept has been put forward, which initially used carbonate solution absorb CO2, and then provided obtained bicarbonate as nutrition for microalgae growth to avoid the challenge of low CO2 solubility and carbon fixation efficiency in the conventional process. In this work, the proposed hybrid system was further intensified via integrating soybean wastewater nutrition removal with bicarbonate-carbon (NH4HCO3 and KHCO3) conversion. The investigation results indicated that the maximum biomass productivity (0.74 g L-1) and carbon bioconversion efficiency (46.9%) were achieved in low-NH4HCO3 concentration system with pH adjusted to 7. pH adjustment of different bicarbonate systems also enhanced total nitrogen (TN), total phosphorus (TP) and chemical oxygen demand (COD) removal efficiency up to 87.5%, 99.5% and 77.6%, respectively. In addition, maximum neutral lipid (14.4 mg L-1·d-1) and polysaccharide (14.5 mg L-1·d-1) productivities could be obtained in the KHCO3 systems, while higher crude protein productivity (48.1 mg L-1·d-1) was yielded in the NH4HCO3 systems.
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Affiliation(s)
- Chunfeng Song
- Tianjin Key Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, 92 Weijin Road, Nankai District, Tianjin, PR China.
| | - Xiaoxuan Han
- Tianjin Key Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, 92 Weijin Road, Nankai District, Tianjin, PR China
| | - Yiting Qiu
- Tianjin Key Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, 92 Weijin Road, Nankai District, Tianjin, PR China
| | - Zhengzheng Liu
- Tianjin Key Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, 92 Weijin Road, Nankai District, Tianjin, PR China
| | - Shuhong Li
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Engineering and Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Yutaka Kitamura
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki, 305-8572, Japan
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48
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Sahoo S, Mahapatra SR, Das N, Parida BK, Rath S, Misra N, Suar M. Functional elucidation of hypothetical proteins associated with lipid accumulation: Prioritizing genetic engineering targets for improved algal biofuel production. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.101887] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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49
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Feng P, Xu Z, Qin L, Asraful Alam M, Wang Z, Zhu S. Effects of different nitrogen sources and light paths of flat plate photobioreactors on the growth and lipid accumulation of Chlorella sp. GN1 outdoors. BIORESOURCE TECHNOLOGY 2020; 301:122762. [PMID: 31972402 DOI: 10.1016/j.biortech.2020.122762] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 01/05/2020] [Accepted: 01/06/2020] [Indexed: 05/20/2023]
Abstract
To assess the potential of Chlorella sp. GN1 for producing biodiesel raw materials in flat plate photobioreactors (FPPs) outdoors, we optimized the nitrogen sources and concentrations for the growth of the algae. The effects of different light paths of FPPs on the growth, lipid accumulation, and fatty acids of Chlorella sp. GN1 were also studied. As the light path of the FPPs was reduced, the alga could accumulate lipids rapidly, achieving high lipid content and lipid productivity outdoors. The highest lipid content obtained was 53.5%, when the light path was 5 cm. In addition, the lipid productivity was 66.7 mg L-1 day-1. The main fatty acids were C16/C18, accounting more than 90% of the total fatty acids. Results showed that Chlorella sp. GN1 had the ability to accumulate large quantities of lipids in FPPs outdoors and was a promising microalgal species for biofuel production.
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Affiliation(s)
- Pingzhong Feng
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Key Laboratory of Renewable Energy, Guangzhou 510640, China; Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China
| | - Zhongbin Xu
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Key Laboratory of Renewable Energy, Guangzhou 510640, China; Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China
| | - Lei Qin
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Key Laboratory of Renewable Energy, Guangzhou 510640, China; Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China
| | - Md Asraful Alam
- School of Chemical Engineering, Zhengzhou University, Zhengzhou, 450001, China
| | - Zhongming Wang
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Key Laboratory of Renewable Energy, Guangzhou 510640, China; Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China
| | - Shunni Zhu
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Key Laboratory of Renewable Energy, Guangzhou 510640, China; Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China.
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50
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Abstract
The need to reduce costs associated with the production of microalgae biomass has encouraged the coupling of process with wastewater treatment. Emerging pollutants in municipal, industrial, and agricultural wastewaters, ranging from pharmaceuticals to metals, endanger public health and natural resources. The use of microalgae has, in fact, been shown to be an efficient method in water-treatment processes and presents several advantages, such as carbon sequestration, and an opportunity to develop innovative bioproducts with applications to several industries. Using a bibliometric analysis software, SciMAT, a mapping of the research field was performed, analyzing the articles produced between 1981 and 2018, aiming to identifying the hot topics and trends studied until now. The application of microalgae on water bioremediation is an evolving research field that currently focuses on developing efficient and cost-effective treatments methods that also enable the production of add-value products, leading to a blue and circular economy.
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