Dextran: History
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Elsa Díaz-Montes

Dextran is an exopolysaccharide (EPS) synthesized by lactic acid bacteria (LAB) or their enzymes in the presence of sucrose. Dextran is composed of a linear chain of d-glucoses linked by α-(1→6) bonds, with possible branches of d-glucoses linked by α-(1→4), α-(1→3), or α-(1→2) bonds, which can be low (<40 kDa) or high molecular weight (>40 kDa). The characteristics of dextran in terms of molecular weight and branches depend on the producing strain, so there is a great variety in its properties. Dextran has commercial interest because its solubility, viscosity, and thermal and rheological properties allow it to be used in food, pharmaceutical, and research areas. 

  • lactic acid bacteria
  • exopolysaccharides
  • dextran
  • structure
  • properties

1. Introduction

Lactic acid bacteria (LAB) are microorganisms that produce lactic acid as the main or only product of carbohydrate fermentation (heterofermentation or homofermentation, respectively). The nutritional requirements are complex, since they are based on vitamins, minerals, fatty acids, amino acids, peptides, and carbohydrates, which are usually in their natural habitats [1]. LAB have been isolated from dairy foods, meats, cereals, vegetables, soil, water, and vaginal waste. According to their characteristics and taxonomy, LAB include bacteria belonging to the genera Aerococcus, Alloiococcus, Carnobacterium, Dolosigranulum, Enterococcus, Globicatella, Lactococcus, Lactobacillus, Leuconostoc, Oenococcus, Pediococcus, Streptococcus, Vaiscoccus, and Weiscoccus [2]. LAB are considered probiotic bacteria because they can be incorporated into food to improve the consumer′s intestinal microbial balance, and they are also generally recognized as safe (GRAS) because they are not pathogenic for humans [3]. On the other hand, they are responsible for a great diversification of flavors and textures of food products, which is why they are mainly used to produce different fermented products such as yogurt, cheese, sourdoughs, pickles, sausages, and soy products [4]. In addition, some LAB can produce extracellular polysaccharides (called exopolysaccharides, EPS) that are repeat units of sugars such as glucose, galactose, and rhamnose, which are secreted during bacterial growth [5]. EPS can be classified into two groups depending on the units that comprise it. Heteropolysaccharides consist of different monosaccharide units, for example, xanthan and gellan. Homopolysaccharides are composed of repeating units of a single type of monosaccharides (e.g., glucose or fructose), for example, glucans and fructans. Levan and inulin are the fructans produced by LAB, while the most commonly produced glucans are cellulose, pullulan, curdlan, mutan, alternan, and dextran [6]. These natural polysaccharides have been used as carriers, encapsulants, thickeners, binders, lubricants, and additives in the pharmaceutical and food industries [7]. However, the most important EPS for medical and industrial use is dextran, which was initially believed to be synthesized only by Leuconostoc mesenteroides, but subsequent research reported its segregation by another type of LAB (see Section 2) [8]. The literature on the identification or characterization of dextrans produced by LAB has been increasing in the past decade. Therefore, the aim of this review is to show the advances that have been made in the discovery and characterization of new dextrans, their structural characteristics (molecular weight, links, and branches), and a brief description of their possible applications in medical, food, and research areas. In addition, emphasis is placed on extraction sources for dextran-producing bacterial strains.

2. Synthesis of Dextran

Dextran is synthesized in a particular way by LAB when exposed to a medium with sucrose as a carbon source [8]. In some LAB (e.g., Lactobacillus), sucrose can enter the cell directly via the phosphotransferase system (PTS) and metabolize to form d-lactate or become dextran [9]. Bacterial dextransucrases, located extracellularly, are responsible for hydrolyzing sucrose in its fructose and glucose monomers, forming an intermediate with glucose (glycosyl-enzyme) to later carry out their polymerization and form dextran [10], while the resulting fructose enters the bacteria through PTS to meet its metabolic demand [11]. LAB that report dextran production are mainly of the genus Leuconostoc, Weissella, Lactobacillus, and Streptococcus [10], which have been isolated from different plant sources (e.g., Agave salmiana and pummelo) [12][13] and fermented products (e.g., rice batter, cabbage, idli batter, and pickles) [14][15][16][17]. However, dextran can also be synthesized via enzymatic, directly using dextransacarases (sucrose: 1,6-α-d-glucan 6-α-d-glucosyltransferase, EC 2.4.1.5) [18], which polymerize the glucoses of the sucrose in dextran.
In industry, dextran is obtained through the culture of Leuconostoc mesenteroides NRRL B512, because it is considered a bacteria generally recognized as safe (GRAS) and very stable [19]. The fermentation of the NRRL B512 strain is carried out in a sucrose medium, which is nourished with yeast extracts, malt extracts, casein, peptone, and tryptone; in addition, low levels of calcium and phosphate are added [20][21][22][23]. During fermentation, the pH drops from 7 to 5 due to the generation of lactic acid; therefore, non-ionic detergents are usually added to maintain the stability of the bacteria and its enzymes [8]. In the clinical area, dextran is usually obtained from the acid hydrolysis (e.g., sulfuric and hydrochloric acids) of the native dextran from Leuconostoc mesenteroides NRRL B512, which allows controlling the molecular weights of the resulting dextrans [24][25].

3. Characteristics and Properties of Dextran

Dextran is a complex glucan formed by a main chain of d-glucoses linked by α-(1→6) bonds with possible branches of d-glucoses with α-(1→4), α-(1→3), or α-(1→2) bonds [26]. Dextrans have molecular weight of up to 440 MDa [27], and they can be classified into two types according to the length of their chains—those with molecular weight greater than 40 kDa are simply called dextrans [8], while those with molecular weight less than 40 kDa can be called oligodextrans [28]. However, some authors name high molecular weight dextran, low molecular weight dextran, and just dextran to generalize [29].
Variations in dextran characteristics (e.g., molecular weight and branching) cause its properties to be different [15][30]. The main chain of dextran with α-(1→6) bonds adopts a helical shape, which is modified by the presence of branches (α-(1→2), α-(1→3) or α-(1→4)), such that the linear structure of glucan is repeatedly folded [31][32][33].
The solubility and rheological properties of dextran are affected by its molecular weight and branching [34]. The solubility of polymers refers to the interaction of the molecule with water through interactions by hydrogen bridges [35]. Some research asserts that if the dextran molecule were totally linear (without branches), it would be totally soluble, because its hydroxy groups (–OH) would be exposed to interact with water molecules [36]. Other investigations affirm that the greater the number of branches, the greater the solubility of the dextran due to the increase in amorphous areas in the molecule that favor water adsorption and retention [31][32][33]. There are even reports that, in general, all low molecular weight polysaccharides have a higher solubility compared to long chain polysaccharides [37]. There is no direct relationship between the characteristics of the molecule and the variation of the properties [14][38][39][40][41]. However, regardless of the degree of solubility, dextrans are considered soluble EPS due to their ability to incorporate large amounts of water and form hydrogels [42].

This entry is adapted from the peer-reviewed paper 10.3390/polysaccharides2030033

References

  1. Voidarou, C.; Antoniadou, M.; Rozos, G.; Tzora, A.; Skoufos, I.; Varzakas, T.; Lagiou, A.; Bezirtzoglou, E. Fermentative foods: Microbiology, biochemistry, potential human health benefits and public health issues. Foods 2021, 10, 1–27.
  2. Mozzi, F. Lactic acid bacteria. In Encyclopedia of Food Health; Elsevier: Amsterdam, The Netherlands, 2016; pp. 501–508. ISBN 9780123849533.
  3. Bintsis, T. Lactic acid bacteria: Their applications in foods. J. Bacteriol. Mycol. Open Access 2018, 6, 89–94.
  4. Narvhus, J.A.; Axelsson, L. Lactic acid bacteria. In Encyclopedia of Food Sciences and Nutrition; Academic Press: San Diego, CA, USA, 2003; pp. 3465–3472. ISBN 012227055X.
  5. Welman, A.D.; Maddox, I.S. Exopolysaccharides from lactic acid bacteria: Perspectives and challenges. Trends Biotechnol. 2003, 21, 269–274.
  6. Laws, A.; Gu, Y.; Marshall, V. Biosynthesis, characterisation, and design of bacterial exopolysaccharides from lactic acid bacteria. Biotechnol. Adv. 2001, 19, 597–625.
  7. Yadav, H.; Karthikeyan, C. Natural polysaccharides: Structural features and properties. In Polysaccharide Carriers for Drug Delivery; Maiti, S., Jana, S., Eds.; Elsevier Ltd.: Amsterdam, The Netherlands, 2019; pp. 1–17. ISBN 9780081025536.
  8. Heinze, T.; Liebert, T.; Heublein, B.; Hornig, S. Functional polymers based on dextran. In Polysaccharides II; Klemm, D., Ed.; Springer: Berlin/Heidelberg, Germany, 2006; pp. 199–291. ISBN 9783540371021.
  9. Prechtl, R.M.; Janßen, D.; Behr, J.; Ludwig, C.; Küster, B.; Vogel, R.F.; Jakob, F. Sucrose-induced proteomic response and carbohydrate utilization of lactobacillus sakei TMW 1.411 during dextran formation. Front. Microbiol. 2018, 9, 1–13.
  10. Kothari, D.; Das, D.; Patel, S.; Goyal, A. Dextran and food application. In Polysaccharides; Gopal Ramawat, K., Mérillon, J.-M., Eds.; Springer International Publishing: Gewerbestrasse, AG, Switzerland, 2014; pp. 735–752. ISBN 9783319162973.
  11. Besrour-Aouam, N.; Fhoula, I.; Hernández-Alcántara, A.M.; Mohedano, M.L.; Najjari, A.; Prieto, A.; Ruas-Madiedo, P.; López, P.; Ouzari, H.-I. The role of dextran production in the metabolic context of Leuconostoc and Weissella Tunisian strains. Carbohydr. Polym. 2020, 253, 117254.
  12. Castro-Rodríguez, D.; Hernández-Sánchez, H.; Yáñez-Fernández, J. Structural characterization and rheological properties of dextran produced by native strains isolated of Agave salmiana. Food Hydrocoll. 2019, 90, 1–8.
  13. Baruah, R.; Maina, N.H.; Katina, K.; Juvonen, R.; Goyal, A. Functional food applications of dextran from Weissella cibaria RBA12 from pummelo (Citrus maxima). Int. J. Food Microbiol. 2016, 242, 124–131.
  14. Lule, V.K.; Singh, R.; Pophaly, S.D.; Poonam Tomar, S.K. Production and structural characterisation of dextran from an indigenous strain of Leuconostoc mesenteroides BA08 in whey. Int. J. Dairy Technol. 2016, 69, 520–531.
  15. Aman, A.; Siddiqui, N.N.; Qader, S.A.U. Characterization and potential applications of high molecular weight dextran produced by Leuconostoc mesenteroides AA1. Carbohydr. Polym. 2012, 87, 910–915.
  16. Sawale, S.D.; Lele, S.S. Statistical optimization of media for dextran production by Leuconostoc sp., isolated from fermented Idli batter. Food Sci. Biotechnol. 2010, 19, 471–478.
  17. Miao, M.; Huang, C.; Jia, X.; Cui, S.W.; Jiang, B.; Zhang, T. Physicochemical characteristics of a high molecular weight bioengineered α-D-glucan from Leuconostoc citreum SK24.002. Food Hydrocoll. 2015, 50, 37–43.
  18. Alcalde, M.; Plou, F.J.; Martín, M.T.; Remaud, M.; Monsan, P.; Ballesteros, A. Stability in the presence of organic solvents of dextransucrase from Leuconostoc mesenteroides NRRL B-512F immobilized in calcium-alginate beads. Prog. Biotechnol. 1998, 15, 535–540.
  19. BeMiller, J.N. Dextran. In Encyclopedia of Food Sciences and Nutrition; Academic Press: San Diego, CA, USA, 2003; pp. 1772–1773. ISBN 012227055X.
  20. DeBelder, A.N. Dextran. In Industrial gums-Polysaccharides and their derivates; Whistler, R.L., BeMiller, J.N., Eds.; Academic Press, Inc.: London, UK, 1993; pp. 399–425. ISBN 0127462538.
  21. Jeanes, A. Dextrans and pullulans: Industrially significant α-D-Ggucans. In Extracellular Microbial Polysaccharides; Sandford, P.A., Allen, L., Eds.; American Chemical Society: Washington, DC, USA, 1977; pp. 284–298. ISBN 9780841203723.
  22. Koepsell, H.J.; Tsuchiya, H.M. Enzymatic synthesis of dextran. J. Bacteriol. 1952, 63, 293–395.
  23. Tsuchiya, H.M.; Koepsell, H.J.; Corman, J.; Bryant, G.; Bogard, M.O.; Feger, V.H.; Jackson, R.W. The effect of certain cultural factors on production of dextransucrase by Leuconostoc mesenteroides. J. Bacteriol. 1952, 64, 521–526.
  24. Wolff, I.A.; Mehltretter, C.L.; Mellies, R.L.; Watson, P.R.; Hofreiter, B.T.; Patrick, P.L.; Rist, C.E. Production of clinical-type dextran-Partial hydrolytic depolymerization and fractionation of the dextran from Leuconostoc mesenteroides strain NRRL B-512. Ind. Eng. Chem. 1954, 46, 370–377.
  25. Zief, M.; Brunner, G.; Metzendorf, J. Fractionation of partially hydrolyzed dextran. J. Am. Pharm. Assoc. Am. 1956, 48, 119–121.
  26. Bhavani, A.L.; Nisha, J. Dextran-The polysaccharide with versatile uses. Int. J. Pharma Bio Sci. 2010, 1, 569–573.
  27. Zarour, K.; Llamas, M.G.; Prieto, A.; Rúas-Madiedo, P.; Dueñas, M.T.; de Palencia, P.F.; Aznar, R.; Kihal, M.; López, P. Rheology and bioactivity of high molecular weight dextrans synthesised by lactic acid bacteria. Carbohydr. Polym. 2017, 174, 646–657.
  28. Foster, J.H.; Killen, D.A.; Jolly, P.C.; Kirtley, J.H. Low molecular weight dextran in vascular surgery: Prevention of early thrombosis following arterial recosntruction in 85 cases. Ann. Surg. 1966, 163, 764–770.
  29. Esmaeilnejad-Moghadam, B.; Mokarram, R.R.; Hejazi, M.A.; Khiabani, M.S.; Keivaninahr, F. Low molecular weight dextran production by Leuconostoc mesenteroides strains: Optimization of a new culture medium and the rheological assessments. Bioact. Carbohydr. Diet. Fibre 2019, 18, 100181.
  30. Caipang, C.M.A.; Lazado, C.C. Nutritional impacts on fish mucosa: Immunostimulants, pre- and probiotics. In Mucosal Health in Aquaculture; Beck, B.H., Peatman, E., Eds.; Academic Press: London, UK, 2015; pp. 211–272. ISBN 9780124171862.
  31. Balani, K.; Verma, V.; Agarwal, A.; Narayan, R. Physical, thermal, and mechanical properties of polymers. In Biosurfaces: A Materials Science and Engineering Perspective; Balani, K., Verma, V., Agarwal, A., Narayan, R., Eds.; John Wiley & Sons, Inc.: Hoboken, NJ, USA, 2015; pp. 329–344. ISBN 9781118299975.
  32. Monnerie, L. Mechanical properties of polymeric materials. In Statistical Models for the Fracture of Disordered Media; Herrmann, H.J., Roux, S., Eds.; Elsevier B.V.: Amsterdam, The Netherlands, 1990; pp. 66–76. ISBN 9781483296128.
  33. Whistler, R.L. Solubility of polysaccharides and their behavior in solution. In Carbohydrates in Solution; Horace, S.I., Ed.; American Chemical Society: Washington, DC, USA, 1973; pp. 242–255. ISBN 9780841201781.
  34. Guo, M.Q.; Hu, X.; Wang, C.; Ai, L. Polysaccharides: Structure and solubility. In Solubility of Polysaccharides; Xu, Z., Ed.; Intech Open: London, UK, 2017; pp. 7–21. ISBN 9789535136507.
  35. Antoniou, E.; Tsianou, M. Solution properties of dextran in water and in formamide. J. Appl. Polym. Sci. 2012, 125, 1681–1692.
  36. Suner, S.S.; Sahiner, M.; Sengel, S.B.; Rees, D.J.; Reed, W.F.; Sahiner, N. Responsive biopolymer-based microgels/nanogels for drug delivery applications. In Stimuli Responsive Polymeric Nanocarriers for Drug Delivery Applications: Volume 1: Types and Triggers; Hamdy Makhlouf, A.S., Abul-Thabit, N.Y., Eds.; Woodhead Publishing: Duxford, UK, 2018; pp. 453–500. ISBN 9780081019979.
  37. Shukla, R.; Shukla, S.; Bivolarski, V.; Iliev, I.; Ivanova, I.; Goyal, A. Structural characterization of insoluble dextran produced by Leuconostoc mesenteroides NRRL B-1149 in the presence of maltose. Food Technol. Biotechnol. 2011, 49, 291–296.
  38. Siddiqui, N.N.; Aman, A.; Silipo, A.; Qader, S.A.U.; Molinaro, A. Structural analysis and characterization of dextran produced by wild and mutant strains of Leuconostoc mesenteroides. Carbohydr. Polym. 2014, 99, 331–338.
  39. Han, J.; Hang, F.; Guo, B.; Liu, Z.; You, C.; Wu, Z. Dextran synthesized by Leuconostoc mesenteroides BD1710 in tomato juice supplemented with sucrose. Carbohydr. Polym. 2014, 112, 556–562.
  40. Vettori, M.H.P.B.; Franchetti, S.M.M.; Contiero, J. Structural characterization of a new dextran with a low degree of branching produced by Leuconostoc mesenteroides FT045B dextransucrase. Carbohydr. Polym. 2012, 88, 1440–1444.
  41. Gil, E.C.; Colarte, A.I.; El Ghzaoui, A.; Durand, D.; Delarbre, J.L.; Bataille, B. A sugar cane native dextran as an innovative functional excipient for the development of pharmaceutical tablets. Eur. J. Pharm. Biopharm. 2008, 68, 319–329.
  42. Campos, F.D.S.; Ferrari, L.Z.; Cassimiro, D.L.; Ribeiro, C.A.; De Almeida, A.E.; Gremião, M.P.D. Effect of 70-kDa and 148-kDa dextran hydrogels on praziquantel solubility. J. Therm. Anal. Calorim. 2016, 123, 2157–2164.
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