Extremophilic Exopolysaccharides: Biotechnologies and Wastewater Remediation

Abstract

Various microorganisms thrive under extreme environments, like hot springs, hydrothermal vents, deep marine ecosystems, hyperacid lakes, acid mine drainage, high UV exposure, and more. To survive against the deleterious effect of these extreme circumstances, they form a network of biofilm where exopolysaccharides (EPSs) comprise a substantial part. The EPSs are often polyanionic due to different functional groups in their structural backbone, including uronic acids, sulfated units, and phosphate groups. Altogether, these chemical groups provide EPSs with a negative charge allowing them to (a) act as ligands toward dissolved cations as well as trace, and toxic metals; (b) be tolerant to the presence of salts, surfactants, and alpha-hydroxyl acids; and (c) interface the solubilization of hydrocarbons. Owing to their unique structural and functional characteristics, EPSs are anticipated to be utilized industrially to remediation of metals, crude oil, and hydrocarbons from contaminated wastewaters, mines, and oil spills. The biotechnological advantages of extremophilic EPSs are more diverse than traditional biopolymers. The present review aims at discussing the mechanisms and strategies for using EPSs from extremophiles in industries and environment bioremediation. Additionally, the potential of EPSs as fascinating biomaterials to mediate biogenic nanoparticles synthesis and treat multicomponent water contaminants is discussed.

First characterization of cultivable extremophile Chroococcidiopsis isolates from a solar panel

“…Specifically, bacteria use biofilms as a structure to resist adverse conditions (Derikvand et al, 2017;Wu et al, 2021). Extremophiles have developed mechanisms that lead to the production of valuable substances in order to survive (Banerjee et al, 2021). Part of the carbohydrates accumulate in cyanobacteria as exopolysaccharides (EPS), depending on species and cultivation conditions, and could contribute to biofilm formation, which protects cyanobacteria against ecological stresses, provides a moist environment, and favors cell aggregation (Potts, 1999;Rossi and De Philippis, 2015;Decho and Gutierrez, 2017).…”

Exopolysaccharides from Marine Microbes: Source, Structure and Application

“…The biological treatments, by contrast, are environmentally friendly. One of the important biological systems’ methods is the use of marine microbial EPS flocculation [ 22 ]. These EPS have a significant impact on the physical and chemical properties of microbial aggregates [ 18 ], which is conducive to flocculation and the precipitation of impurities in sewage.…”

“…The complex and diverse structure of EPS endows them with unique biological activities and functions [ 13 , 14 , 15 , 16 ]. Now, EPS, as a major active component of marine microbial resources [ 5 , 17 ], have become a new research hotspot, with advances in modern separation and analysis techniques [ 12 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. First, because the EPS are produced by marine microorganisms, this is an important factor for them to survive in these extreme environments, such as high pressure, high temperatures, and high salinity [ 25 ].…”

“…A novel EPS, named as EPS-S3 from marine bacterium Pantoea sp., could accelerate cutaneous wound healing via the Wnt/β-catenin pathway, indicating a prospective use as a new biomaterial for skin tissue regeneration [ 34 ]. Furthermore, EPS synthesized by microorganisms have many advantages over the other polysaccharides isolated from plants, animals, and algae [ 22 ], such as high structure reproducibility, which is not possible for most plant and animal sources, due to their polysaccharide structures dependent on climate, environmental and feed conditions [ 21 ]. In addition, the high yield of EPS can be achievable by optimizing culture conditions and using the techniques of synthetic biology, which is now a promising and new research field.…”

Eurypsychrophilic acidophiles: From (meta)genomes to low-temperature biotechnologies

“…Extremophilic microorganisms are used in a variety of biotechnological applications spanning the biomedical, pharmaceutical, industrial, environmental, and agricultural sectors (Raddadi et al, 2015 ; Banerjee et al, 2021 ; Verma, 2021 ). Applications of low-temperature microorganisms have seen numerous successes in the production of cold active proteases, lipases, and cellulases in food production, chemical synthesis, textile industry, pharmaceutical and molecular biology, bioremediation, and novel antimicrobials [reviewed in Cavicchioli et al ( 2011 ) and Siddiqui ( 2015 )].…”