Applications of Polysaccharide Stalks in Didymosphenia geminata Diatom: Comparison
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Didymosphenia geminata is a species of freshwater diatom that is known as invasive and is propagating quickly around the world. The polysaccharide-based stalks of D. geminata enable versatile potential applications and use as a biopolymer, in drug delivery and wound healing, and as biocompatible scaffolding in cell adhesion and proliferation. Furthermore, the polysaccharide nature of stalks and their metal-adsorption capacity allow them to have excellent wastewater remediation potential.

  • chitin
  • diatoms
  • didymo
  • invasive species
  • polysaccharide structure
  • drug delivery
  • wound dressing

1. Introduction

Diatoms are a type of unicellular microalgae that play a large role in the biosilica production and carbon fixation of the planet [1][2]. Additionally, they are also one of the largest producers of macronutrients such as nitrogen and phosphorus [1]. One species of freshwater diatom, Didymosphenia geminata (Lyngb.) has characteristic biomineralized polysaccharide stalks and blooms whose growth has recently proliferated throughout many aquatic ecosystems [3][4][5][6]. Although the invasive status of D. geminata may sometimes be uncertain, it is not the organisms themselves that have had the largest impact on the local environment but rather the adhesive stalks formed by D. geminata [7][8]. Unfortunately, the detailed chemistry of these fibrous structures has not been known until now. According to the modern view, these stalks are primarily composed of sulfated polysaccharides, proteins, and some uronic acid [3][4] and can spread and grow over 500 µm long and over multiple centimeters thick [8]. They are also able to divide during the cell reproduction process, leading to the production of large, branching, dense mats that can cover stream bottoms, covering areas of over 20 km [4][6][8]. Furthermore, the chemistry of the frustules of D. geminata has also not been well studied.
D. geminata in benthic ecosystems has recently been a focus of research, in part due to the ability of blooms to manipulate and overwhelm the biodiversity of an ecosystem [9]. The presence of these large blooms alters local food-web structures by favoring smaller predators that can move between filaments and alter the composition of other diatoms [5]. The fish community is also affected by D. geminata blooms through changes to benthic invertebrate composition, with some New Zealand ecosystems experiencing a fish biomass decrease as a result [10]. The proliferation of D. geminata blooms also affects water quality, as diatom biodiversity and species composition are often used as measures of changes in environmental conditions [8]. Indeed, these blooms are caused by novel environmental conditions that are becoming increasingly more common due to climate change [11]. One of the largest predictors for the presence of polysaccharide blooms is the low concentration of dissolved phosphorus [7][12]. The formation of stalks is thought to be a way for D. geminata to elevate itself to reach the water column, where there is increased nutrient uptake [7][12][13]. While D. geminata bloom proliferation may have devastating effects on ecosystems, it can be suggested that its relatively large nanocalcite- and polysaccharide-based stalks may be used in many, more positive applications.

2. Applications of D. geminata as a Biomaterial

D. geminata is a relatively new finding and has many potential uses in biomedicine and as a biomaterial for drug delivery, cell adhesion, and proliferation [6]. he polysaccharides in the stalk of D. geminata appear to be primarily sulfated xylogalactan, and the stalk was found to be intrinsically hydrophilic, a trait that is one of the first determiners of the extent of protein adsorption [14]. The presence of sulfate groups within polysaccharides shows an improvement in the immune system and would be beneficial to the nutraceutical industry [15]. The intrinsic biocompatible nature of D. geminata is attributed to its similarity in structure to glycosaminoglycans, which are a vital component in the tissue extracellular matrix [16].

Zglobicka in 2013 examined how previous studies had cast stalks of D. geminata as capable of adhering to multiple kinds of substrates because they were built in concentric circles of materials of variable compositions [17]. The chemical composition of the stalk seems to largely be unknown, but it is agreed that the main composition is amorphous silica [17][18]. The use of silica and biosilica in bone regeneration is well studied. It is understood to improve bone regeneration and increase bone density and is thought to play a role in the stabilization of collagen in the bone matrix [19]. The specific structure of D. geminata and its diatom frustules made of silica are especially beneficial with regard to drug delivery due to characteristics such as high permeability and low density [20]. D. geminata also exhibits anticancer properties [2]. As seen in Figure 12, the diatom has a nanosized porous silica capsule, which allows controlled drug release. The drug itself can be added to the external and internal surface of the diatom and then released based on need. The drug can be loaded onto the nanoparticles directly through noncovalent interactions like electrostatic bonding, hydrogen bonding, van der Waals forces, pi–pi stacking, and hydrophobic interactions [21].
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Figure 12.
The mechanism of drug release from the porous diatom microshell
[2]
.
Wound healing is another potential use for a D. geminata stalk due to its unique sulfated polysaccharide composition. Recent studies have shown that sulfated polysaccharides from seaweeds are harvested and studied as promising sources of wound dressings due to their intrinsic biological activity [22].
With its use in therapeutic purposes within the nutraceutical and pharmaceutical industries, D. geminata could have potential uses in the treatment of diseases such as COVID-19 as a filler for corresponding drugs.

3. D. geminata Applications in Wastewater Treatment

The composition and structure of D. geminata, in particular its multiphase-biomineralized polysaccharide stalks [23], allow for potential valuable applications in wastewater treatment due to its metal-adsorption capacities [24]. The use of microalgae in wastewater treatment is not a novel concept, and research has revealed numerous advantages, such as low cost, high metal-ion uptake, and excellent metal selectivity [25]. Due to the availability of D. geminata in various regions, recent studies have emerged investigating the feasibility of using its biomass for heavy-metal remediation in water treatment [4][26]. Polysaccharide-containing biomass, which makes up the extracellular stalks of D. geminata, is considered to be an excellent adsorbent of heavy metals, predominantly via functional groups [24]. Wysokowski et al. [24] found that purified D. geminata stalks had considerable adsorption capabilities for both nickel(II) and cadmium(II) ions but were especially efficient in the adsorption of lead(II) ions, with a maximum adsorption capacity of 175.48 mg g−1 [4][24]. This Pb(II)-adsorption capacity is quite high in comparison to other microalgae biosorbents and, in fact, is almost comparable to the metal-sorption capabilities of some macroalgae [4][26][25][27]. The use of D. geminata for heavy-metal adsorption would be especially advantageous in treating industrial wastewater that has been contaminated with lead, which is a priority pollutant associated with high toxicity [28]. There is also potential for D. geminata stalks to act as an adsorbent for U(V) ions, with preliminary results showing a 96% decrease in U(V) concentration from adsorption via D. geminata nonwoven fabric [20].
Utilizing nonliving D. geminata biomass for heavy-metal remediation in water treatment has also proven to be advantageous in terms of sorbent regeneration and reusability [26][29]. Although dried D. geminata stalks appear to decrease in mechanical resistance upon adsorption of metals, Wysokowski et al. demonstrated the potential for the material still to go through multiple adsorption and desorption phases, with only a slight decrease in uptake capacity [4][30].
There is evidence to suggest that the presence of sulfur-based functional groups on D. geminata stalks specifically contributes to the excellent adsorption capabilities of the biomaterial [4][26]. The presence of either sulfate esters or sulfonic groups on the isolated polysaccharide stalks has been confirmed through infrared spectroscopy [15]. Metal adsorption on D. geminata stalks is thought to occur via a complex mechanism based on ion exchange between hydroxyl and sulfur-based functional groups and metal ions, forming complex ions and coordination bonds (Figure 24) [4][26].
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Figure 24. Schematic diagram for the adsorption of metal ions on D. geminata stalks [4]. The adsorption mechanism is based on ion exchange between groups on the adsorbent surface (hydroxyl and sulfonic groups) and metal ions, leading to the formation of coordination bonds, as one might observe in the diagram.

4. D. geminata’s Economic Impacts

Taking advantage of algae species such as D. geminata in industrial practices could be advantageous in reducing the negative impact of invasive species while reusing them as sustainable and natural resources. D. geminata’s ability to treat wastewater and transform it into agricultural fertilizers could bring great economic benefits with its usage; however, it has yet to be determined whether the accompanying side effects of D. geminata application would potentially suppress the profitability of the water area. Thus, considerations of its negative impact and growth-controlling plans should be made before D. geminata application.
While the commercial impact of D. geminata is unknown, studies that investigate the adverse effects of various existing aquatic invasive species (AISs) that are brought to fisheries could be referenced. A report analyzing the economic impact of an AIS on the industries of the Great Lakes states of the U.S. by Rosaen et al. summarized some of the major profit losses by invasive species involving tourism [31]. This nonmarketed loss that is largely due to the rapid spread of AIS can be the result of one of three phenomena: direct operational cost, reduced demand, or decreased productivity. The prevention of AIS spreading requires regular maintenance, which includes but is not limited to water-pipe scraping and chemical treatment. Recreational boating and commercial fishing companies have always relied on the diverse fish species of the local water area. Direct competition within the same habitat due to the occupation of space by AIS can lead to lowered fish stocks and even the extinction of certain species. In addition to the loss of fish population and diversity, the overall demand for tourism can be impacted in several ways. Common examples of reduced customer interest could be that the quality of fish, either its size or health, can no longer meet the expectation of the recreationists, or that beach areas are being occupied with dead fish and fermented rotten algae. Most businesses faced major difficulties opening up, and less-established companies were challenged with permanent shutdown. A reported annual loss of $50 million was due to the reduced demand for businesses and tourism alone [32].
New Zealand, one of the most chronically infected areas, paid an economic cost of $158 million in the first eight years post-D. geminata discovery without government intervention [14]. Even with a continuous investment in D. geminata control efforts, the preventions themselves could be a nuisance to some of the local businesses. One case study performed in New Zealand focused on the nonmarketed impact that D. geminata has on recreational angling industries. AIS management is often extremely complex, with most situations requiring rapid responses to efficiently limit the spread; for one reason, AIS directly competes for the same habitat as some of the most demanded fish species. As reported by Bergey et al., D. geminata blooms are observed to thrive in rocky and low-nutrient cold-water streams that are ideal for trout populations [33]. The immediate closure of some of the most demanded trout-fishing streams, regardless of their state of D. geminata infection, cost more than it would have to remain open at the time of this study. As a result of the decreased angling accessibility due to mainstem river closure, the fishing effort is thus transferred to smaller stems, threatening the vulnerable fish stock.
It is important to note that the occurrence of D. geminata in New Zealand should be considered a special case and not a common situation found in rivers of other regions. In Canada, a study done in 2008 reported that due to the distinct climate in Quebec, salmon rivers are not as impacted as in regions such as the Great Lakes and New Zealand [14]. In addition, studies done on D. geminata’s impact on salmon production in British Columbia showed no significance, and some infested rivers of Vancouver were even observed to have huge improvements due to possible natural control mechanisms [34], although D. geminata has not yet become a major threat to Canadian fish rivers. However, Canada has endured a reported total of $5.5 billion loss due to the indirect economic burden and the direct management cost from the 16 recognized species [35]. Given the above, the impact of D. geminata should still be studied in depth and closely monitored when applying it to the suggested purposes mentioned in this paper.

 

References

  1. Whitton, B.A.; Ellwood, N.T.W.; Kawecka, B. Biology of the Freshwater Diatom Didymosphenia: A Review. Hydrobiologia 2009, 630, 1–37.
  2. Hussein, H.A.; Abdullah, M.A. Anticancer Compounds Derived from Marine Diatoms. Mar. Drugs 2020, 18, 356.
  3. Sundareshwar, P.V.; Upadhayay, S.; Abessa, M.; Honomichl, S.; Berdanier, B.; Spaulding, S.A.; Sandvik, C.; Trennepohl, A. Didymosphenia geminata: Algal Blooms in Oligotrophic Streams and Rivers. Geophys. Res. Lett. 2011, 38.
  4. Wysokowski, M.; Bartczak, P.; Żółtowska-Aksamitowska, S.; Chudzińska, A.; Piasecki, A.; Langer, E.; Bazhenov, V.V.; Petrenko, I.; Noga, T.; Stelling, A.L.; et al. Adhesive Stalks of Diatom Didymosphenia geminata as a Novel Biological Adsorbent for Hazardous Metals Removal. CLEAN-Soil Air Water 2017, 45, 1600678.
  5. Ladrera, R.; Gomà, J.; Prat, N. Effects of Didymosphenia geminata Massive Growth on Stream Communities: Smaller Organisms and Simplified Food Web Structure. PLoS ONE 2018, 13, e0193545.
  6. Ejaz, H.; Somanader, E.; Dave, U.; Ehrlich, H.; Rahman, M.A. Didymo and Its Polysaccharide Stalks: Beneficial to the Environment or Not? Polysaccharides 2021, 2, 69–79.
  7. Elwell, L.C.; Gillis, C.-A.; Kunza, L.A.; Modley, M.D. Management Challenges of Didymosphenia geminata. Diatom Res. 2014, 29, 303–305.
  8. Taylor, B.W.; Bothwell, M.L. The Origin of Invasive Microorganisms Matters for Science, Policy, and Management: The Case of Didymosphenia geminata. Bioscience 2014, 64, 531–538.
  9. Brand, C.; Grech, M. Recent Invasion of Didymosphenia geminata (Lyngbye) M. Schmidt in a Patagonian Regulated River Promotes Changes in Composition and Density of Macroinvertebrate Community. Biol. Invasions 2020, 22, 1903–1915.
  10. Jellyman, P.G.; Harding, J.S. Disentangling the Stream Community Impacts of Didymosphenia geminata: How Are Higher Trophic Levels Affected? Biol. Invasions 2016, 18, 3419–3435.
  11. Jones, L.R.; Manrique, J.M.; Uyua, N.M.; Whitton, B.A. Genetic Analysis of the Invasive Alga Didymosphenia geminata in Southern Argentina: Evidence of a Pleistocene Origin of Local Lineages. Sci. Rep. 2019, 9, 18706.
  12. Bothwell, M.L.; Taylor, B.W.; Kilroy, C. The Didymo Story: The Role of Low Dissolved Phosphorus in the Formation of Didymosphenia geminata Blooms. Diatom Res. 2014, 29, 229–236.
  13. Kilroy, C.; Bothwell, M. Environmental Control of Stalk Length in the Bloom-Forming, Freshwater Benthic Diatom Didymosphenia geminata (Bacillariophyceae). J. Phycol. 2011, 47, 981–989.
  14. Bothwell, M.L.; Spaulding, S.A. Synopsis of the 2007 International Workshop on Didymosphenia geminate. In Proceedings of the 2007 International Workshop on Didymosphenia geminate; Fisheries and Oceans Canada: Ottawa, ON, Canada, 2008; 96p.
  15. Figueroa, F.A.; Abdala-Díaz, R.; Hernández, V.; Pedreros, P.; Aranda, M.; Cabrera-Pardo, J.R.; Pérez, C.; Becerra, J.; Urrutia, R. Invasive Diatom Didymosphenia geminata as a Source of Polysaccharides with Antioxidant and Immunomodulatory Effects on Macrophage Cell Lines. J. Appl. Phycol. 2020, 32, 93–102.
  16. Wahab, I.F.; Razak, S.I. Polysaccharides as Composite Biomaterials. In Composites from Renewable and Sustainable Materials; InteahOpen: London, UK, 2016; pp. 65–84.
  17. Zgłobicka, I. Aspects of Structural Biology of Didymosphenia geminata (Lyngb.) M. Schmidt (Bacillariophyta). IJA 2013, 15, 291–310.
  18. Zglobicka, I. Frustules of Didymosphenia geminata as a Modifier of Resins. Mater. Eng. 2018, 1, 10–16.
  19. Arora, M.; Arora, E. The Promise of Silicon: Bone Regeneration and Increased Bone Density. J. Arthrosc. Jt. Surg. 2017, 4, 103–105.
  20. Zgłobicka, I. Exploratory Study of the Use of Didymosphenia geminata Stalks as a Functional Biomaterial. Ph.D. Thesis, Division of Materials Design, The Warsaw University of Technology, Warszawa, Poland, 2015.
  21. Wang, N.; Cheng, X.; Li, N.; Wang, H.; Chen, H. Nanocarriers and their loading strategies. Adv. Healthc. Mater. 2019, 8, 1801002.
  22. Andryukov, B.G.; Besednova, N.N.; Kuznetsova, T.A.; Zaporozhets, T.S.; Ermakova, S.P.; Zvyagintseva, T.N.; Chingizova, E.A.; Gazha, A.K.; Smolina, T.P. Sulfated Polysaccharides from Marine Algae as a Basis of Modern Biotechnologies for Creating Wound Dressings: Current Achievements and Future Prospects. Biomedicines 2020, 8, 301.
  23. Ehrlich, H.; Motylenko, M.; Sundareshwar, P.V.; Ereskovsky, A.; Zgłobicka, I.; Noga, T.; Płociński, T.; Tsurkan, M.V.; Wyroba, E.; Suski, S.; et al. Multiphase Biomineralization: Enigmatic Invasive Siliceous Diatoms Produce Crystalline Calcite. Adv. Funct. Mater. 2016, 26, 2503–2510.
  24. Na, Y.; Lee, J.; Lee, S.H.; Kumar, P.; Kim, J.H.; Patel, R. Removal of Heavy Metals by Polysaccharide: A Review. Polym.-Plast. Technol. Mater. 2020, 59, 1770–1790.
  25. Zeraatkar, A.K.; Ahmadzadeh, H.; Talebi, A.F.; Moheimani, N.R.; McHenry, M.P. Potential Use of Algae for Heavy Metal Bioremediation, a Critical Review. J. Environ. Manag. 2016, 181, 817–831.
  26. Reinoso-Guerra, E.; Aristizabal, J.; Arce, B.; Zurob, E.; Dennett, G.; Fuentes, R.; Suescún, A.V.; Cárdenas, L.; da Cunha, T.H.R.; Cabezas, R.; et al. Nanostructured Didymosphenia geminata-Based Membrane for Efficient Lead Adsorption from Aqueous Solution. J. Environ. Chem. Eng. 2021, 9, 105269.
  27. Ubando, A.T.; Africa, A.D.M.; Maniquiz-Redillas, M.C.; Culaba, A.B.; Chen, W.-H.; Chang, J.-S. Microalgal Biosorption of Heavy Metals: A Comprehensive Bibliometric Review. J. Hazard. Mater. 2021, 402, 123431.
  28. Arbabi, M.; Hemati, S.; Amiri, M. Removal of Lead Ions from Industrial Wastewater: A Review of Removal Methods. Int. J. Epidemiol. Res. 2015, 2, 105–109.
  29. Pavithra, K.G.; Kumar, P.S.; Jaikumar, V.; Vardhan, K.H.; SundarRajan, P. Microalgae for Biofuel Production and Removal of Heavy Metals: A Review. Environ. Chem. Lett. 2020, 18, 1905–1923.
  30. Zgłobicka, I.; Chlanda, A.; Woźniak, M.; Łojkowski, M.; Szoszkiewicz, R.; Mazurkiewicz-Pawlicka, M.; Święszkowski, W.; Wyroba, E.; Kurzydłowski, K.J. Microstructure and Nanomechanical Properties of Single Stalks from Diatom Didymosphenia geminata and Their Change Due to Adsorption of Selected Metal Ions. J. Phycol. 2017, 53, 880–888.
  31. Rosaen, A.L.; Grover, E.A.; Spencer, C.W. The Costs of Aquatic Invasive Species to Great Lakes States; Anderson Economic Group: East Lansing, MI, USA, 2016; 51p.
  32. Beville, S.T.; Kerr, G.N.; Hughey, K.F.D. Valuing Impacts of the Invasive Alga Didymosphenia geminata on Recreational Angling. Ecol. Econ. 2012, 82, 1–10.
  33. Bergey, E.A.; Cooper, J.T.; Phillips, B.C. Substrate Characteristics Affect Colonization by the Bloom-Forming Diatom Didymosphenia geminata. Aquat. Ecol. 2010, 44, 33–40.
  34. Ministère du Développement Durable, de L’environnement et des Parcs; Ministère des Ressources Naturelles et de la Faune. What Is Didymo and How Can We Prevent It from Spreading in Our Rivers? Ministère du Développement Durable, de l’Environnement et des Parcs: Rouyn-Noranda, QC, Canada, 2008; 13p.
  35. Government of Canada, Fisheries and Oceans Canada. A Canadian Action Plan to Address the Threat of Aquatic Invasive Species. Available online: https://www.dfo-mpo.gc.ca/species-especes/publications/ais-eae/plan/page01-eng.html (accessed on 24 October 2021).
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