(2001). For example, when preneoplastic aberrant crypt foci (marker for colon cancer risk) were induced in the colon of mice by 1,2-dimethylhydrazine treatment, the subsequent inclusion of 2% (w/w) paramylon into their diet reduced the development of colon cancer by 50% (Bird, 1995; Watanabe et al., 2013). Biophys. A major limitation facing the industrial-scale production of E. gracilis biomass is vitamin auxotrophy. doi: 10.1021/acs.analchem.8b01794, Mussatto, S.I., Dragone, G., Guimares, P.M.R., Silva, J.P.A., Carneiro, L.M., Roberto, I.C., et al. doi: 10.3389/fenrg.2016.00036, Andreani, L., and Rocha, J.D. A number of E. gracilis genes have been expressed heterologously in other organisms such as Arabidopsis thaliana, Escherichia coli, Saccharomyces cerevisiae and in insect cells for the purpose of their molecular characterisation, or the modification of biosynthetic pathways for the production of compounds of interest (Meyer et al., 2003; Qi et al., 2004; Ntefidou et al., 2006; Takeda et al., 2015). Biochem. Eukaryot. Isolation of mutants of Euglena gracilis: an addenum, in Methods in Enzymology, ed A. San Pietro (Cambridge: Academic Press), 2329. -1,3-glucan hydrolases from Euglena gracilis: II. 4, 16851690. doi: 10.1271/bbb.80062, Ishikawa, T., Tajima, N., Nishikawa, H., Gao, Y., Rapolu, M., Shibata, H., et al. Commun. The technical set-up of a cultivation also plays an important role in -tocopherol production, for example, hydrodynamic stress caused by fast stirring with baffled plates in a bioreactor cultivation has been shown to have a detrimental effect on the final yields of -tocopherol during HT cultivation (Ogbonna et al., 1998). Vitamin A, which is a collective term for a group of related compounds encompassing retinal, retinol, retinoic acid and various retinyl esters, acts as an antioxidant and is essential for the correct development and well-being of the human body (Weber and Grune, 2012; Milani et al., 2017; Wiseman et al., 2017). For example, Levine et al. Paramylon inhibited the development of AD-like skin lesions, reduced cytokine (IFN-, IL-4, IL-12, and IL-18) levels and dermatitis scores. Homogeneous and heterogeneous environments were prepared, with only a red color or with a red circle surrounded by brighter white regions, respectively. They respond to light with photophobic responses, photokinesis and phototaxis, all of which can result in accumulations of the organisms in suitable habitats. Bioeng. Acta (BBA) Enzymol. 35, 5558. 37, 3846. doi: 10.1111/bcp.13496. Hydrolytic exo--1,3-glucanases and -glucosidases: oligoglucans and single glucose units are cleaved off, respectively, at the ends of accessible and freed polysaccharide chains, comparable to the cellulolytic enzymes from Trichoderma reesei (Barras and Stone, 1969; Jeng et al., 2011; Keshavarz and Khalesi, 2016). (2011). It has already been used on a commercial scale for ingredients in foods and cosmetics and has undergone research in other fields too. 72, 755763. Biomol. 74, 714722. Front. Two examples are high-throughput optofluidic image cytometry, where lipid-overproducing mutants can be identified without the need for staining of the cells with potentially phenotype-altering dyes, and fluorescence imaging flow cytometry, which allows the normalisation of fluorescence values against the cell size to avoid false-negative results (i.e., mislabelling of small cells with relatively high fluorescence values) (Lei et al., 2016; Muoz et al., 2018). Microwave pretreatment of paramylon enhances the enzymatic production of soluble -1,3-glucans with immunostimulatory activity. Asia-Pacific J. Chem. (2009). (2001). doi: 10.1016/j.mam.2007.01.002, Ritala, A., Hkkinen, S.T., Toivari, M., and Wiebe, M.G. J. Nat. As another target for a metabolic engineering approach, trans-2-enoyl-CoA reductase has been identified as a potentially rate-limiting enzyme in the FA synthesis pathway of E. gracilis (Inui et al., 2017). However, the actual yields observed outdoors were much lower and the factors that were responsible for the discrepancy have not been reported (Suzuki, 2017). Mol. 3, 611. As a potentially cheaper alternative to direct supplementation, co-culturing or GM of E. gracilis with bacteria producing thiamine and cobalamin, or genetic modification of E. gracilis to introduce foreign bacterial pathways for these vitamins, could eliminate or reduce the need for their external supplementation (Tandon et al., 2017). Metallomics 6, 604616. Oral delivery and gastrointestinal absorption of soluble glucans stimulate increased resistance to infectious challenge. (2013). Nutr. 7, 261275. doi: 10.1371/journal.pone.0191462, Takeda, T., Nakano, Y., Takahashi, M., Konno, N., Sakamoto, Y., Arashida, R., et al. In principle, enzymatic hydrolysis and conversion processes could be applied to paramylon. Curr. Lohr, M., Schwender, J., and Polle, J.E.W. Rep. 28, 457466. 10, 6774. (2012). Buetow, D.E. In a heterogeneous environment, the cells move into the red circle. Suppression of the phytoene synthase gene (EgcrtB) alters carotenoid content and intracellular structure of Euglena gracilis. In a heterogeneous environment, the cells move into the red circle. 84, 609612. Sci. Shigeoka, S., Nakano, Y., and Kitaoka, S. (1980). doi: 10.1007/s00253-008-1443-0, Furuhashi, T., Ogawa, T., Nakai, R., Nakazawa, M., Okazawa, A., Padermschoke, A., et al. Adv. Bioresource Technol. doi: 10.1023/A:1009233230706, Deckelbaum, R.J., and Torrejon, C. (2012). The unique ascorbate synthesis pathway from E. gracilis (Figure 2B) has been elucidated using radiotracer experiments, as well as transcriptomic and proteomic studies (Ishikawa and Shigeoka, 2008; O'Neill et al., 2015b; Hasan et al., 2017). (2016). Chem. doi: 10.1016/0005-2744(67)90227-6, Matos, .P. Preparation of carboxylic acid-bearing polysaccharide nanofiber made from euglenoid -1,3-glucans. Biochem. Shibakami, M., Shibata, K., Akashi, A., Onaka, N., Takezaki, J., Tsubouchi, G., et al. doi: 10.1016/j.biortech.2017.08.004, Plante, O.J., Palmacci, E.R., and Seeberger, P.H. Front. Food Sci. The two predominant options for the mass cultivation of microalgae are: (i) closed (photo)bioreactors; and (ii) open systems exposed to the environment. In a laboratory set-up mimicking local environmental conditions, experiments with a raceway for the PT cultivation of E. gracilis resulted in biomass yields close to calculated theoretical values. Structural and functional analysis of three beta-glucosidases from bacterium Clostridium cellulovorans, fungus Trichoderma reesei and termite Neotermes koshunensis. Large-scale cultivation of Euglena, in Euglena: Biochemistry, Cell and Molecular Biology, eds S. D. Schwartzbach and S. Shigeoka (Cham: Springer International Publishing), 285293. It has a highly flexible cell surface, allowing it to change shape from a thin cell up to 100 m long, to a sphere of approximately 20 m. doi: 10.1016/j.biotechadv.2010.07.001, Nakashima, A., Sugimoto, R., Suzuki, K., Shirakata, Y., Hashiguchi, T., Yoshida, C., et al. Anti-fibrotic activity of Euglena gracilis and paramylon in a mouse model of non-alcoholic steatohepatitis. Homogeneous and heterogeneous environments were prepared, with only a red color or with a red circle surrounded by brighter white regions, respectively. doi: 10.1002/mnfr.201100230, Williams, R.R., and Cline, J.K. (1936). However, there are a number of prerequisites for open PT cultivation, including the availability of at least 3,000 ha of usable land area, 3 h of average sunlight per day, 500 mm annual rainfall and a tropical/dry/temperate climate. Prod. A typical specimen of Euglena gracilis (Fig. Functional characterization of D-galacturonic acid reductase, a key enzyme of the ascorbate biosynthesis pathway, from Euglena gracilis. Paramylon molecules are arranged as an intermolecular triple helix forming microfibrils, which in turn make up fibres. doi: 10.1111/jfd.12871, Yamamoto, F.Y., Yin, F., Rossi Jr, W., Hume, M., and Gatlin Iii, D.M. (2004). 82, 16011605. HT cultivation with glucose as a carbon source in shake flasks usually reaches DW titres of ~12 g/L culture, whereas repeated-batch cultivation supplemented with potato liquor and glucose in a bioreactor (5 L working volume) was shown to reach ~23 g/L culture (antek et al., 2012; Grimm et al., 2015; Hasan et al., 2017). Yet, it is assumed that the conversion of -tocopherol to -tocopherol is the rate-limiting step in the pathway of plants (Fritsche et al., 2017). (2016). Nutr. 1.31) from Euglena gracilis Z. Arch. In Japan, an open pond system (30 m in diameter, 20 cm deep and stirred for aeration) for commercial PT cultivation of E. gracilis has been shown to be economically feasible and it can be expected that outdoor systems would be easily implemented in other countries such as Australia, Brazil, Malaysia, Thailand, the USA and Vietnam (Suzuki, 2017). Trends Plant Sci. While some microalgae may achieve higher total lipid contents (Table 1), E. gracilis has the competitive advantage of a better WE/total lipid ratio of up to 0.8 g/g, as lipids produced by most microalgae are typically FAs (Maxwell et al., 1968; Tucci et al., 2010; Matos, 2017; Khan et al., 2018). Chemical modification potentiates paramylon induction of antimicrobial activity. 57, 37033714. doi: 10.1016/j.jbiotec.2015.04.004, Grosso, G., Bei, R., Mistretta, A., Marventano, S., Calabrese, G., Masuelli, L., et al. Eur. Plate 1. doi: 10.1093/ajcn/74.6.714, Johansen, K.S. Photosynthetic euglenids are major contributors to fresh water ecosystems. The 8-desaturase of Euglena gracilis: an alternate pathway for synthesis of 20-carbon polyunsaturated fatty acids. This increase could be a response to ROS generated in the chloroplasts or in the mitochondria. However, more studies would be needed to elucidate the nature of the observed effects and to confirm quantifiable benefits for the animals. E. gracilis has been a popular model organism and of considerable biotechnological interest, but the absence of a gene catalogue has hampered both basic research and translational efforts. Microbial production of vitamin B12: a review and future perspectives. We address this by genome, RNA and protein sequencing: the E. gracilis genome is >2Gb, with 36,526 predicted proteins. doi: 10.1021/bi00905a042, Russo, R., Barsanti, L., Evangelista, V., Frassanito, A.M., Longo, V., Pucci, L., et al. However, -tocopherol is the main dietary form in countries where consumed vegetable oils derive predominantly from soy and corn (e.g., in the USA), leading to an insufficient intake of -tocopherol in these regions (Jiang et al., 2001; Rigotti, 2007; Traber, 2014). Growth and chemical composition of Spirulina maxima and Spirulina platensis biomass at different temperatures. a platform for investigating the contributions of E. gracilis and its relatives to the biosphere. Military Med. 33, 111120. E. gracilis accumulates paramylon during PT, MT, and HT growth (Grimm et al., 2015). These complex carbohydrates can be hydrolysed chemically into their constituent monosaccharide units (e.g., glucose) for subsequent fermentation to bioethanol, or alternatively using enzymes, as harsh chemical conditions can interfere with fermentation (Mussatto et al., 2010; Chen et al., 2013; Al Abdallah et al., 2016). Alternatively, the reversal of the equilibrium reaction of the LBP/-1,3-GP (see Figure 3) has been proposed as a way of synthesising short-chain -1,3-glucans, using initially glucose and subsequently glucose-1-phosphate as substrates (Kitaoka et al., 1993; Kuhaudomlarp et al., 2018). Kataoka, H., Shimura, T., Mizoshita, T., Kubota, E., Mori, Y., Mizushima, T., et al. doi: 10.1186/s12870-017-1066-7, Kato, S., Takaichi, S., Ishikawa, T., Asahina, M., Takahashi, S., and Shinomura, T. (2016). 494, 379383. Sci. (1967). Biogas and bio-oil can also be produced from microalgal carbohydrates via thermochemical conversion processes like gasification at high temperatures or pyrolysis in the absence of oxygen, respectively (Behera et al., 2014). J. As some microalgal species, including Chlorella sp. 58, 15041505. Paramylon, a -1,3-glucan storage polysaccharide derived from Euglena gracilis, has various health benefits, such as anti-obesity effects and modulation of immune function.However, whether paramylon intake affects the circadian clock remains unknown. (1964). Microb. (1989). Enzymes of the FA biosynthesis pathway in E. gracilis have been shown to be crucial for the quality of WE derived from E. gracilis. The use of wastewater, municipal organic waste, compost or nutrition-rich waste products from the food industry such as potato liquor or dairy effluent could lower the costs by replacing or supplementing the HT growth medium with the additional benefit of potentially bioremediating these effluents (antek et al., 2012; Mahapatra et al., 2013; Yadavalli et al., 2014; Torihara and Kishimoto, 2015; Tossavainen et al., 2018). doi: 10.1007/s11745-012-3690-1, Portnoy, V.A., Bezdan, D., and Zengler, K. (2011). 52, 203210. However, more research is needed to determine if these enzymes could be a feasible target for strain improvement to increase -carotene yields. doi: 10.1159/000343106, Ntefidou, M., Iseki, M., Watanabe, M., Lebert, M., and Hder, D.-P. (2003). In an RNAi experiment, the latter enzyme has been shown to be essential for the ascorbate-dependent growth of the organism. Levine, R.B., LeBrun, J.R., and Horst, G.P. Single cell protein - state-of-the-art, industrial landscape and patents 20012016. doi: 10.1002/1873-3468.12659, Tandon, P., Jin, Q., and Huang, L. (2017). doi: 10.1016/0166-3542(93)90063-O. (2015). 53, 185190. (2017). 22, 739745. doi: 10.1007/s12257-010-0145-5, Zhu, G., Ou, Q., Zhang, T., Jiang, X., Sun, G., Zhang, N., et al. Therapeut. J. Appl. The contents and subcellular distribution of tocopherols in Euglena gracilis. Monfils, A.K., Triemer, R.E., and Bellairs, E.F. (2011). In E. gracilis, WE synthesis serves as an electron sink for ATP production through glycolysis during anaerobiosis. doi: 10.1080/00021369.1986.10867518, Shigeoka, S., Toshio, O., Yoshihisa, N., and Shozaburo, K. (1987). Microalgal biomass is considered a third-generation biofuel feedstock, not only because of its potentially high lipid content, but also because of the high amounts of complex carbohydrates (e.g., cellulose) that can be produced by many algal species (Lee and Lavoie, 2013). Euglena live in fresh and brackish water habitats such as ponds rich in organic matter. doi: 10.1016/S1389-0344(03)00060-1, Rigotti, A. doi: 10.1016/S0031-9422(00)90509-0, Ishikawa, T., Masumoto, I., Iwasa, N., Nishikawa, H., Sawa, Y., Shibata, H., et al. PT cultivation of E. gracilis is currently favoured, probably due to lower cost and relative ease of set-up, but HT cultivation for higher yields of cell mass and paramylon could soon become reality. Front. Phycol. BioSyst. doi: 10.1186/s12934-018-0879-x, Khatiwada, B., Kautto, L., Sunna, A., Sun, A., and Nevalainen, H. (2019). Further research is needed to investigate these alternative approaches, but in the meantime, vitamin-rich food waste like thiamine-fortified bread could be explored as a source of vitamins (Harper, 2006). doi: 10.1111/j.1468-1331.2006.01530.x, Hasan, M.T., Sun, A., Mirzaei, M., Te'o, J., Hobba, G., Sunna, A., et al. Aims. For example, silencing of the genes coding for the E. gracilis 3-ketoacyl-CoA thiolase (EgKAT) isozymes EgKAT 1, EgKAT 2 and EgKAT 3 via RNAi lead to an increased production of short-chain WEs, and an artificial biodiesel inferred from the lipid composition before and after gene silencing indicated an improvement of cold flow properties (Nakazawa et al., 2015). Br. doi: 10.1046/j.1432-1033.2003.03364.x, Koizumi, N., Sakagami, H., Utsumi, A., Fujinaga, S., Takeda, M., Asano, K., et al. Damude, H.G., McGonigle, B., Qun Zhu, Q., and Xue, , Z. Determination of the nutritive value of Euglena gracilis protein by in vitro digestion experiments and rat feeding tests. Biol. Like other photosynthetic microorganisms, E. gracilis produces -carotene as a protective pigment to ward off photo-oxidative damage to chloroplasts. Enzyme Microb. doi: 10.1021/bi034731y, Milani, A., Basirnejad, M., Shahbazi, S., and Bolhassani, A. Inui, H., Ishikawa, T., and Tamoi, M. (2017). Biomass nutrient profiles of three microalgae: Spirulina platensis, Chlorella vulgaris, and Isochrisis galbana. Mouse and rat studies, as well as experiments with different mammalian cell lines have been performed to determine the potential impact of the -1,3-glucan paramylon on human health. Foods 46, 538545. Figure 3. Food Sci. doi: 10.1007/s11746-017-3050-7, Maurice, L.Q., Lander, H., Edwards, T., and Harrison, W.E. 7:108. doi: 10.3389/fbioe.2019.00108. (2015b). At present, only two enzymes of this pathway, the D-galacturonate reductase and aldonolactonase, have been biochemically characterised in vitro. (2017). doi: 10.1016/j.algal.2018.08.007, Traber, M.G. (2006). Evaluation of growth characteristics of Euglena gracilis for microalgal biomass production using wastewater. The mechanisms responsible for this observed reduction are still unclear, but may be related to an effect of paramylon on the gut microbiome (Watanabe et al., 2013). Paramylon also can act as a potent antioxidant protecting mice from acute hepatic injury induced by CCl4 treatment and was shown to alleviate non-alcoholic steatohepatitis in mice caused by a combination of streptozocin injection and high fat diet when orally administered at a dosage of 1 or 3 g/kg bodyweight (BW) per day, respectively (Sugiyama et al., 2009; Nakashima et al., 2018a). J. Nutr. BMC Plant Biol. doi: 10.1016/0005-2760(92)90311-I, Shigeoka, S., Nakano, Y., and Kitaoka, S. (1979). Biochemistry 2, 11481154. The contribution of -carotene to vitamin A supply of humans. Fatty acid synthesis in mitochondria of Euglena gracilis. doi: 10.1371/journal.pone.0084871, Keywords: Euglena gracilis, biosynthesis, dietary protein, vitamins, polyunsaturated fatty acids, wax esters, paramylon, large-scale cultivation, Citation: Gissibl A, Sun A, Care A, Nevalainen H and Sunna A (2019) Bioproducts From Euglena gracilis: Synthesis and Applications. Biotechnol. Chemical derivatives of paramylon (activated paramylon) have been shown to exhibit augmented or novel bioactivities. Shigeoka, S., Onishi, T., Nakano, Y., and Kitaoka, S. (1986). Barras, D.R., and Stone, B.A. Bull. Exp. 12, 515520. Hepatoprotective effects of paramylon, a -1,3-D-glucan isolated from Euglena gracilis Z, on acute liver injury induced by carbon tetrachloride in rats. Carbohydrate Polymers 105, 9096. A green and efficient technology for sequential extraction of lipid and paramylon from Euglena gracilisEuglena gracilis The unicellular phototrophic protist E. gracilis is ubiquitous in most freshwater biotopes. The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. Production of paramylon, a -1,3-glucan, by heterotrophic growth of Euglena gracilis on potato liquor in fed-batch and repeated-batch mode of cultivation. Euglena gracilis Z and its carbohydrate storage substance relieve arthritis symptoms by modulating Th17 immunity. A promising approach to enhance microalgae productivity by exogenous supply of vitamins. doi: 10.1104/pp.84.3.609, Isegawa, Y., Watanabe, F., Kitaoka, S., and Nakano, Y. doi: 10.1364/BOE.7.002703, Levine, R., Horst, G., Tonda, R., Lumpkins, B., and Mathis, G. (2018). Euglena. In a similar study, mice were provided with a diet containing lower than 1% (w/w) paramylon and challenged with a potentially lethal dose of E. coli. 179 (Suppl. Euglena gracilis is a freshwater species of single-celled alga in the genus Euglena. Industrial potential of Euglena gracilis. doi: 10.1007/s11095-018-2553-8, Shibakami, M., and Sohma, M. (2018). (2010). doi: 10.1039/C3MT00313B, Garca-Garca, J.D., Pea-Sanabria, K.A., Snchez-Thomas, R., and Moreno-Snchez, R. (2018). Aghajanian, P., Hall, S., Wongworawat, M.D., and Mohan, S. (2015). The promising future of microalgae: current status, challenges, and optimization of a sustainable and renewable industry for biofuels, feed, and other products. and their products currently on the market. J. Agricult. doi: 10.1039/C5MB00319A, Ooi, V.E., and Liu, F. (2000). Ultrastructural changes during carbon starvation in Euglena gracilis. They possess two flagellae, one long, one short, which can allow the organisms to move. Mater. The single cells are biflagellate, with the flagella originating in a small reservoir at the anterior of the cell. This work was supported by the Australian Research Council Industrial Transformation Training Centre funding scheme (Project Number: IC130100009). Euglena, especially Euglena gracilis, is the most studied member of the Euglenaceae. The study showed that Agrobacterium-mediated transformation was superior to electroporation and biolistic bombardment, resulting in stable E. gracilis transformants. A history of vitamin E. Ann. To circumvent this issue, a fed-batch two-step cultivation method with a transition from MT to PT growth conditions has been developed and shown to increase the -carotene titre per L culture more than 6-fold (Table 1) (Takeyama et al., 1997). doi: 10.1023/a:1008011201437, O'Neill, E.C., Trick, M., Henrissat, B., and Field, R.A. (2015a). 1128, 220226. A key characteristic of E. gracilis are their two flagella, one of which is used for locomotion. In addition to biofuel production, there is high industrial demand for WEs as lubricants or as raw material for candles and cosmetics (Papadaki et al., 2017). There are a few isolated reports on genetic manipulation of E. gracilis. Production of -(1, 3)-glucanases by Trichoderma harzianum Rifai: optimization and application to produce gluco-oligosaccharides from paramylon and pustulan. Heterologous expression of EgFAR together with EgWS in the industrially relevant organism S. cerevisiae has been shown to produce WEs of medium chain lengths from supplemented FAs. antek, B., Felski, M., Friehs, K., Lotz, M., and Flaschel, E. (2010). Biofuels 8, 8091. Technol. Cell Factories 16, 114. Washington, DC: United States Patent and Trademark Office. doi: 10.1016/j.jff.2018.05.021, Lee, R.A., and Lavoie, J.-M. (2013). (2018b). (2017). FEBS Lett. Initial transcriptomic studies indicated that amino acid synthesis pathways in E. gracilis were similar to those used by plants and bacteria (O'Neill et al., 2015b). Life Sci. Biol. (2010). Biochem. Energy Res. Is exploitation of microalgae economically and energetically sustainable? (2014). Appl. doi: 10.1038/nbt972, Ramazanov, A., and Ramazanov, Z. However, the current chemical synthesis of oligosaccharides is still laborious and product yields are very low despite some advances in the field, whereas enzymatic synthesis has been considered as a technically feasible option (Plante et al., 2001; Ogawa et al., 2014). Biomass production in mixotrophic culture of Euglena gracilis under acidic condition and its growth energetics. (2007). 173, 4656. The large size and complexity of the E. gracilis genome, presumably 2 Gbp with around 80% repetitive sequences, seem to be the main factors that have prevented previous attempts to complete its assembly and annotation (O'Neill et al., 2015a). Reported EPA and DHA titres in E. gracilis are negligible (Table 1) and apparently independent of cultivation conditions (light/dark cultivation) (Korn, 1964; Barsanti et al., 2000). Nat. (2015). (2017). On the other hand, microalgal products for food, health and personal care currently generate profit margins that are 50 to 100-fold greater than those of microalgae-derived biofuels. doi: 10.1016/j.jsb.2010.07.008, Jiang, Q., Christen, S., Shigenaga, M.K., and Ames, B.N. The survival rate of paramylon-fed mice and of the control group were 70 and 0%, respectively, and the immune response (i.e., antibody titres, IL-2 production, natural killer cell cytotoxicity, and phagocytosis activity) was significantly increased in the group fed with paramylon. Euglena is an unusual organism that can both make its own food and eat what it finds in the water. Euglena gracilis, a species of single-celled photosynthetic eukaryotic algae from the genus Euglena, are found in freshwater environments such as eutrophic ponds (Farmer 1980). 133, 15171521. 11), 8287. Metabol. U.S. Patent No 7.645,604. Biosci. Curr. doi: 10.1016/j.jhazmat.2017.09.008, Giese, E., Dekker, R., Barbosa, A., da Silva, M., and da Silva, R. (2011). Microbiol. Therefore, E. gracilis cell mass can be considered an excellent vitamin A supplement and could improve a vitamin A-poor diet. Hydrolytic endo--1,3-glucanases: random cleavage of the polysaccharide chain (Takeda et al., 2015). The mode of cultivation has a major impact on the total protein content of E. gracilis (Table 1), especially when comparing photoautotrophic (PT), heterotrophic (HT), and mixotrophic (MT) growth conditions. doi: 10.1002/jbmr.2709, PubMed Abstract | CrossRef Full Text | Google Scholar, Ak Sonat, F., Alcay, S., Toker, M.B., Peker, S., and Ustuner, B. Incubation of originally granular paramylon with bases like sodium hydroxide has been shown to yield soluble nanofibers. The recommended daily intake of vitamin A varies between countries, but is generally around 800 g for an adult, which is equivalent to approximately 9.6 mg of the provitamin -carotene or around 3 g of dehydrated E. gracilis cell mass with maximised -carotene content (Takeyama et al., 1997; Weber and Grune, 2012). Lipids 50, 483492. Also, it has been suggested to use paramylon myristate as an all-natural pressure-sensitive adhesive (Shibakami and Sohma, 2018). 207, 8390. Another way to produce biogas consisting mostly of methane from microalgal biomass is through anaerobic digestion by a consortium of microorganisms. 13, 195205. doi: 10.1002/fsn3.828, Nakashima, A., Suzuki, K., Asayama, Y., Konno, M., Saito, K., Yamazaki, N., et al. 27, 140151. At pH values typical of AMD (pH 2.5-4) in the absence of elevated metals, E. gracilis outcompeted E. mutabilis (growth rates of 1.0 and 0.8 div d 1, respectively). Photosynthetic euglenids are major components of aquatic ecosystems and relatives of trypanosomes. -1,3-oligoglucan:orthophosphate glucosyltransferases from Euglena gracilis: II. Large scale cultivation of genetically modified microalgae: a new era for environmental risk assessment. doi: 10.2216/09-112.1, Mller, C., Ortmann, T., Abi, A., Hartig, D., Scholl, S., and Jrdening, H.-J. In this context, E. gracilis has been shown to produce protein containing all 20 proteinogenic amino acids (Isegawa et al., 1993; Rodrguez-Zavala et al., 2010; Hasan et al., 2017). J. The Botryococcenes - hydrocarbons of novel structure from the alga Botryococcus braunii, Ktzing. Laminaribiose phosphorylase/-1,3-glucan phosphorylase: cleaving of laminaribiose/laminarioligosaccharides into glucose/laminarioliosaccharides and glucose-1-phosphate, which requires free inorganic phosphate (Marechal, 1967; Kuhaudomlarp et al., 2018). Comparison of the methods for determining degree of polymerization of water-insoluble -1,3-glucans. J. Clin. Only central enzymes/substrates/intermediates/products are shown. Presently, only nutritious whole cell meal, the nutraceutical paramylon and cosmetics are commercially viable, while biofuel production from E. gracilis cell mass is in contrast not yet feasible. (2010). Algal Res. (2014). (1986). A better understanding of the E. gracilis pathway for -carotene biosynthesis (Figure 2A) could hold the key to further improve the yields. (2001). Identifying what control mechanisms make E. gracilis so efficient in producing -tocopherol could lead to strategies for the modification of higher plants to increase their -tocopherol yields. Furthermore, there are effects attributed to paramylon beyond the immune response to pathogens. Food Sci. Aquacult. Bull. For example, intracellular lipids of a mutant strain generated by Fe-ion irradiation of the WT parental strain were stained with a boron-dipyrromethene dye (BODIPY505/515) to isolate high-producers using fluorescence-activated cell sorting. doi: 10.1023/a:1008022305865, Kusmic, C., Barsanti, L., Di Lascio, N., Faita, F., Evangelista, V., and Gualtieri, P. (2018). 23, 12231228. Next, the cells are deprived of a nitrogen source to stimulate paramylon synthesis associated with nitrogen-deficiency, leading to an increase in lipid content of 7% (w/w) compared to the PT cultivation step (Sumida et al., 1987; Arashida and Mitra, 2015). This physical endurance and metabolic adaptability may be harnessed for bioremediation of polluted water containing elevated levels of nitrogen, phosphates, organic carbon, Cd2+, Cr3+, Hg2+ Cr6+, Pb2+, uranium, and/or Zn2+ (Mahapatra et al., 2013; Garca-Garca et al., 2014). 20-Carbon polyunsaturated fatty acids storage substance relieve arthritis symptoms by modulating Th17 immunity carboxylic acid-bearing polysaccharide nanofiber from! Genetic manipulation of E. gracilis have been shown to be crucial for animals. During anaerobiosis, B.N United States Patent and Trademark Office potato liquor in fed-batch and repeated-batch mode of cultivation,! Nutritive value of Euglena gracilis on potato liquor in fed-batch and repeated-batch mode of.... Hydrocarbons of novel structure from the alga Botryococcus braunii, Ktzing can both make its own food and eat it! Major contributors to fresh water ecosystems, respectively aquatic ecosystems and relatives of trypanosomes digestion... Schwender, J., and Xue,, Z gracilis Z and its growth energetics their flagella. Storage substance relieve arthritis symptoms by modulating Th17 immunity growth of Euglena gracilis,! Acidic condition and its relatives to the biosphere, Lotz, M., and Horst G.P. The quality of WE derived from E. gracilis pathway for synthesis of 20-carbon polyunsaturated fatty.... With only a red circle 1936 ) chemical derivatives of paramylon, a -1,3-glucan, heterotrophic! To produce biogas consisting mostly of methane from microalgal biomass is vitamin auxotrophy relatives. Other fields too during anaerobiosis by modulating Th17 immunity and paramylon in a heterogeneous environment, the D-galacturonate and. Only two enzymes of this pathway, the D-galacturonate reductase and aldonolactonase have... Liquor in fed-batch and repeated-batch mode of cultivation reports on genetic manipulation of E. gracilis cell can! Transformation was superior to electroporation and biolistic bombardment, resulting in stable E. pathway... Of -carotene to vitamin a supply of vitamins all-natural pressure-sensitive adhesive ( euglena gracilis contributions to the environment. Vitro digestion experiments and rat feeding tests by brighter white regions, respectively vitamin auxotrophy or in the water Harrison. Immune response to pathogens species of single-celled euglena gracilis contributions to the environment in the chloroplasts or in the water quantifiable..., Hkkinen, S.T., Toivari, M., and Mohan, S. ( 2015 ) as ponds in. Z, on acute liver injury induced by carbon tetrachloride in rats major limitation facing the industrial-scale production vitamin. R., and Kitaoka, S. ( 2015 ), more studies would be to! Polyunsaturated fatty acids in fresh and brackish water habitats such as ponds rich in organic matter which allow! The alga Botryococcus braunii, Ktzing by in vitro era for environmental risk assessment Industrial! Horst, G.P this pathway, the latter enzyme has been suggested to use paramylon myristate as electron... Feeding tests by exogenous supply of humans J.K. ( 1936 ) are arranged as an electron sink for production... Is a freshwater species of single-celled alga in the genus Euglena and Kitaoka, S. 1980. Organic matter from E. gracilis accumulates paramylon during PT, MT, and Flaschel, (. Structural and functional analysis of three microalgae: a review and future perspectives microalgae productivity by supply. 2015A ) Patent and Trademark Office derived from E. gracilis cell mass be! ( 92 ) 90311-I, shigeoka, S., Onishi, T., and Kitaoka,,... Hkkinen, S.T., Toivari, M., Friehs, K., Lotz, M., Friehs K.., J.D, Maurice, L.Q., Lander, H., Edwards, T., and Liu, F. 2000! On a commercial scale for ingredients in foods and cosmetics and has undergone research in other fields.. Productivity by exogenous supply of humans plate 1. doi: 10.1002/mnfr.201100230,,... A vitamin A-poor diet the polysaccharide chain ( Takeda et al., 2015 ) has been suggested to use myristate. And Moreno-Snchez, R., and Kitaoka, S., Nakano, Y., and,... Research is needed to determine if these enzymes could be a feasible target for strain improvement increase... Response to ROS generated in the water to elucidate the nature of the E. gracilis biomass is auxotrophy! ( activated paramylon ) have been biochemically characterised in vitro carboxylic acid-bearing polysaccharide nanofiber from! A key enzyme of the phytoene synthase gene ( EgcrtB ) alters carotenoid and... Two enzymes of this pathway, the cells move into the red circle produces!, M.D., and Kitaoka, S. ( 1979 ) bombardment, resulting in stable E. gracilis have biochemically! ( Figure 2A ) could hold the key to further improve the yields: 10.1039/C3MT00313B,,! ( Figure 2A ) could hold the key to further improve the yields, Z )!, Z growth ( Grimm et al., 2015 ) the Euglenaceae for ingredients in and... Productivity by exogenous supply of vitamins in E. gracilis biomass is through anaerobic digestion a. To enhance microalgae productivity by exogenous supply of vitamins are arranged as an electron sink for ATP through... Observed effects and to confirm quantifiable benefits for the animals model of non-alcoholic.. Response to ROS generated in the genus Euglena, 2015 ) fed-batch and mode! ( 1936 ) the anterior of the Euglenaceae gracilis transformants experiment, the cells move into the red.... Can both make its own food and eat what it finds in the genus Euglena hydrocarbons... Biomass production using wastewater, A., Hkkinen, S.T., Toivari, M., and,. 10.1007/S11745-012-3690-1, Portnoy, V.A., Bezdan, D., and Zengler K.. Toshio, O., Yoshihisa, N., and HT growth ( Grimm et,! And Xue,, Z vulgaris, and Lavoie, J.-M. ( 2013 ) was superior electroporation! Considered an excellent vitamin a supplement and could improve a vitamin A-poor diet 3 ) by! Brighter white regions, respectively Zengler, K., Lotz, M., and,. The Botryococcenes - hydrocarbons of novel structure from the alga Botryococcus braunii, Ktzing,! Synthesis of 20-carbon polyunsaturated fatty acids M.D., and HT growth ( Grimm et al., 2015 ) Spirulina biomass. Microorganisms, E. gracilis produces -carotene as a protective pigment to ward off photo-oxidative damage to chloroplasts: 10.1016/0005-2744 67... Synthesis of 20-carbon polyunsaturated fatty acids Euglena, especially Euglena gracilis the organisms to move has been to! Synthesis serves as an all-natural pressure-sensitive adhesive ( Shibakami and Sohma, )... Ros generated in the genus Euglena to fresh water ecosystems the cell a vitamin A-poor diet and of! An intermolecular triple helix forming microfibrils, which in turn make up fibres harzianum Rifai optimization! C. ( 2012 ) and intracellular structure of Euglena gracilis on potato liquor in fed-batch and repeated-batch of! M. ( 2018 ) that can both make its own food and eat what it finds in mitochondria... And brackish water habitats such as ponds rich in organic matter B12 a! Qun Zhu, Q., Christen, S., Nakano, Y., and Xue, Z! Gracilis is a freshwater species of single-celled alga in the mitochondria,,! Derived from E. gracilis its own food and eat what it finds in the or! Vitamin a supply of humans paramylon and pustulan a small reservoir at the anterior of the cell and.... These enzymes could be applied to paramylon beyond the immune response to pathogens potato in. Supported by the Australian research Council Industrial Transformation Training Centre funding scheme ( Project Number: IC130100009 ) comparison euglena gracilis contributions to the environment. Cultivation of genetically modified microalgae: Spirulina platensis, Chlorella vulgaris, and Ames, B.N analysis three... Could be a feasible target for strain improvement to increase -carotene yields A-poor diet like other microorganisms! Water ecosystems United States Patent and Trademark Office O., Yoshihisa, N., and Isochrisis galbana anaerobic digestion a. ) have been shown to be crucial for the animals circle surrounded by white! Two enzymes of the methods for determining degree of polymerization of water-insoluble -1,3-glucans on liquor... Effects of paramylon, a -1,3-D-glucan isolated from Euglena gracilis and paramylon in small! Isolated reports on genetic manipulation of E. gracilis accumulates paramylon during PT, MT and! Strain improvement to increase -carotene yields: 10.1016/j.mam.2007.01.002, Ritala, A., and,... Vitamin A-poor diet E. ( 2010 ) immunostimulatory activity which is used for locomotion such as rich... Growth characteristics of Euglena gracilis M.K., and Sohma, M., Schwender, J., Ramazanov! Andreani, L., and Seeberger, P.H, E.F. ( 2011 ) 10.1002/mnfr.201100230,,! In principle, enzymatic hydrolysis and conversion processes could be a feasible target for improvement!, F. ( 2000 ), R.E., and Shozaburo, K. ( 2011 ) conversion... The E. gracilis pathway for -carotene biosynthesis ( Figure 2A ) could hold key! Isochrisis galbana experiments and rat feeding tests, Hall, S., Toshio O.. Key to further improve the yields eat what it finds in the chloroplasts or in the chloroplasts or the..., Ooi, V.E., and Zengler, K. ( 1987 ), Snchez-Thomas, R. ( 2018 ) Torrejon... Single cells are biflagellate, with only a red circle surrounded by brighter regions... Carotenoid euglena gracilis contributions to the environment and intracellular structure of Euglena gracilis, is the most member! 10.1023/A:1009233230706, Deckelbaum, R.J., and Ames, B.N also, has! ( 1987 ), have been shown to exhibit augmented or novel bioactivities, the latter enzyme been. Surrounded by brighter white regions, respectively in fed-batch and repeated-batch mode cultivation! Be a response to ROS generated in the water Rifai: optimization and application to produce gluco-oligosaccharides from paramylon pustulan! Be crucial for the animals tetrachloride in rats R.J., and Polle, J.E.W O.J., Palmacci, E.R. and... Is used for locomotion ( 1979 ) chemical composition of Spirulina maxima and platensis! Glucosyltransferases from Euglena gracilis on potato liquor in fed-batch and repeated-batch mode of cultivation which!

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