Bacterial Exopolysaccharides from Extreme Marine Habitats: Production, Characterization and Biological Activities (original) (raw)
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Marine Biotechnology, 2005
Many marine bacteria produce exopolysaccharides (EPS) as a strategy for growth, adhering to solid surfaces, and to survive adverse conditions. There is growing interest in isolating new EPS producing bacteria from marine environments, particularly from extreme marine environments such as deep-sea hydrothermal vents characterized by high pressure and temperature and heavy metal presence. Marine EPS-producing microorganisms have been also isolated from several extreme niches such as the cold marine environments typically of Arctic and Antarctic sea ice, characterized by low temperature and low nutrient concentration, and the hypersaline marine environment found in a wide variety of aquatic and terrestrial ecosystems such as salt lakes and salterns. Most of their EPSs are heteropolysaccharides containing three or four different monosaccharides arranged in groups of 10 or less to form the repeating units. These polymers are often linear with an average molecular weight ranging from 1 × 10 5 to 3 × 10 5 Da. Some EPS are neutral macromolecules, but the majority of them are polyanionic for the presence of uronic acids or ketal-linked pyruvate or inorganic residues such as phosphate or sulfate. EPSs, forming a layer surrounding the cell, provide an effective protection against high or low temperature and salinity, or against possible predators. By examining their structure and chemical-physical characteristics it is possible to gain insight into their commercial application, and they are employed in several industries. Indeed EPSs produced by microorganisms from extreme habitats show biotechnological promise ranging from pharmaceutical industries, for their immunomodulatory and antiviral effects, bone
Potential functions and applications of diverse microbial exopolysaccharides in marine environments
Journal of Genetic Engineering and Biotechnology
Exopolysaccharides (EPSs) from microorganisms are essential harmless natural biopolymers used in applications including medications, nutraceuticals and functional foods, cosmetics, and insecticides. Several microbes can synthesize and excrete EPSs with chemical properties and structures that make them suitable for several important applications. Microbes secrete EPSs outside their cell walls, as slime or as a “jelly” into the extracellular medium. These EPS-producing microbes are ubiquitous and can be isolated from aquatic and terrestrial environments, such as freshwater, marine water, wastewater, and soils. They have also been isolated from extreme niches like hot springs, cold waters, halophilic environments, and salt marshes. Recently, microbial EPSs have attracted interest for their applications such as environmental bio-flocculants because they are degradable and nontoxic. However, further efforts are required for the cost-effective and industrial-scale commercial production of...
Marine Drugs, 2018
The marine environment is the largest aquatic ecosystem on Earth and it harbours microorganisms responsible for more than 50% of total biomass of prokaryotes in the world. All these microorganisms produce extracellular polymers that constitute a substantial part of the dissolved organic carbon, often in the form of exopolysaccharides (EPS). In addition, the production of these polymers is often correlated to the establishment of the biofilm growth mode, during which they are important matrix components. Their functions include adhesion and colonization of surfaces, protection of the bacterial cells and support for biochemical interactions between the bacteria and the surrounding environment. The aim of this review is to present a summary of the status of the research about the structures of exopolysaccharides from marine bacteria, including capsular, medium released and biofilm embedded polysaccharides. Moreover, ecological roles of these polymers, especially for those isolated from...
Exopolysaccharides from marine bacteria: production, recovery and applications
Environmental Sustainability, 2020
Ocean represents an unusual diversity of life. The largest proportion of microbial diversity has been found in the oceanic and terrestrial subsurface respectively. Marine habitats are inhabited by several microbial populations adapted to these ecosystems. Among these populations, bacteria are one of the important and dominant inhabitants of such environments. Marine bacteria themselves or their products such as enzymes, exopolymers, pigments, antimicrobial compounds, and biosurfactants represent a wide range of applications in food, textile, and pharmaceutical industries as well as in many environmental processes. This review aims to present the exopolysaccharide production from marine bacteria and its possible biosynthesis along with recovery of these polymers using various methods. Finally, the applications of these polymers, particularly in the field of bioremediation, are also discussed.
The pharma Innovation, 2018
The exopolysaccharides (EPS) derived from marine bacteria have shown to exhibit versatile applications in diverse biotechnological segments. Therefore a study was done to bio prospect marine bacteria from surface sea water, associated with algae and sand obtained from the coastal area of Someshwar, Mangalore and was screened for exopolysaccharide production. Out of the twenty colonies isolated; two colonies that produced prominent mucoid colonies were selected, designated as YUI6-DR3A and YU17-DR6A, identified using 16S rRNA gene sequencing and the EPS produced by them in Zobell marine broth and MY broth was evaluated using standard spectrophotometric methods. The phylogenetic analyses of the isolates done on the basis of 16S rRNA gene sequence revealed the isolates YU16-DR6A and YU16-DR3A shared 97.54% and 100% similarity respectively to Pseudoalteromonas shioyasakiensis sp. SE3 T. The strains produced appreciable amount of EPS in MY media. The expolysaccharides of these newly isolated strains can be further explored for its applicability in biotechnological industries. Introduction Marine environs cover almost three quarters of earth and contain a vast biological diversity. Marine habitats are highly complex and are the largest continuous ecosystem that consists of extremely variable temperature, salinity, pressure and nutritional conditions. In the oceans, bacteria constitute the most abundant and diverse members of the microbial world. Many reports describe the efficiency of marine bacterial strains in biotechnological applications including human and environmental benefits. The bacteria isolated from these environments are potent sources of various industrially important bioactive compounds such as enzymes, exopolysaccharide (EPS), biosurfactants, antibacterial, antiviral, anticancer compounds with distinctive and diverse compositions. Marine bacteria secrete different compounds based on their habitat and their ecological functions. Many marine bacteria produce exopolysaccharides (EPS) as a strategy for growth, binding to the substratum, to survive unfavorable conditions and also to intra-and inter-specific communication and competition (Corinaldesi et al., 2017)
Marine Invertebrates: Underexplored Sources of Bacteria Producing Biologically Active Molecules
Diversity
The marine bioprospecting could be considered as a new phenomenon, and already potentially more promising than terrestrial one in terms of possible discovery of new compounds. The secondary metabolites produced by associated-bacteria are actually studied for their remarkable role in several fields, including agricultural, industrial, medical, and bioremediation strategies against different contaminants. The use of such renewable sources could be helpful in the streamlining of the patenting process for natural compounds of good quality, produced with lower energy costs and less impact on the environment. Anyway, more improvements in the research and application of bioactive compounds as alternative to the synthetic counterparts have to be carried out for the costs reduction and the large-scale production upgrading. The use of marine invertebrates could help to overcome these difficulties, as hotspots of microbial diversity and favorable matrix for the development of conditions stimulating the production of substances with special activities. This review will deal with the current accepted definitions and recent advances concerning: (i) the marine symbiotic relationships in which microorganisms and invertebrates are involved; (ii) the principal taxa of marine invertebrates that establish interactions with microorganisms, the biodiversity of these latter, and their role in the symbiosis; (iii) we address the state of current literature and knowledge about the bacterial associated communities specialized in biosurfactants (BSs) and extracellular polymeric substances (EPSs) production; and, (iv) their potential biotechnological applications reported still now.
Fermentation Technologies for the Optimization of Marine Microbial Exopolysaccharide Production
Marine Drugs, 2014
In the last decades, research has focused on the capabilities of microbes to secrete exopolysaccharides (EPS), because these polymers differ from the commercial ones derived essentially from plants or algae in their numerous valuable qualities. These biopolymers have emerged as new polymeric materials with novel and unique physical characteristics that have found extensive applications. In marine microorganisms the produced EPS provide an instrument to survive in adverse conditions: They are found to envelope the cells by allowing the entrapment of nutrients or the adhesion to solid substrates. Even if the processes of synthesis and release of exopolysaccharides request high-energy investments for the bacterium, these biopolymers permit resistance under extreme environmental conditions. Marine bacteria like Bacillus, Halomonas, Planococcus, Enterobacter, Alteromonas, Pseudoalteromonas, Vibrio, Rhodococcus, Zoogloea but also Archaea as Haloferax and Thermococcus are here described as EPS producers underlining biopolymer hyperproduction, related fermentation strategies including the effects of the chemical composition of the media, the physical parameters of the growth conditions and the genetic and predicted experimental design tools.
Exopolysaccharides from unusual marine environments inhibit early stages of biofouling
International Biodeterioration & Biodegradation, 2012
Biological fouling in marine and freshwater environments creates a number of problems for engineered structures. The deleterious effects arise from microbial biofilm formation, often followed by successional colonization by a variety of macrofouling organisms. To-date, effective prevention strategies have primarily relied upon antimicrobial agents that usually show toxicity against non-target organisms. While a variety of non-toxic surface modification technologies have been employed, their efficacy has been very limited in in situ environments. We evaluated a number of extracellular polysaccharide (EPS) formulations purified from marine bacteria as potential antifouling agents. EPS from Alteromonas, Pseudomonas, and Vibrio spp. were dip-coated onto cleaned glass slides, placed into a flow cell apparatus with real-time imaging, then exposed to natural flowing seawater under laboratory conditions over a 5 d timeframe. All six of the purified EPS formulations inhibited biofouling (primarily, bacteria) over the test period, with HYD 657, HE 800, HYD 1644 and HYD 1545 showing the most significant reductions in fouling. Surface area fouling was reduced by 90% relative to a cleaned glass control substrate. None of the six formulations evaluated showed any evidence of antimicrobial activity or of cytotoxicity. While the mechanism(s) responsible for the observed fouling inhibition are not fully resolved, it is possible that steric hindrance of primary colonizers may be involved. These preliminary results suggest that bacterial EPS may be an effective inhibitor of the initial stages of biofilm formation and subsequent biofouling activity.
We have studied the exopolysaccharide produced by the type strain of Salipiger mucosus, a species of halophilic, EPS-producing (exopolysaccharide-producing) bacterium belonging to the Alphaproteobacteria. The strain, isolated on the Mediterranean seaboard, produced a polysaccharide, mainly during its exponential growth phase but also to a lesser extent during the stationary phase. Culture parameters influenced bacterial growth and EPS production. Yield was always directly related to the quantity of biomass in the culture. The polymer is a heteropolysaccharide with a molecular mass of 250 kDa and its components are glucose (19.7%, w/w), mannose (34%, w/w), galactose (32.9%, w/w) and fucose (13.4%, w/w). Fucose and fucose-rich oligosaccharides have applications in the fields of medicine and cosmetics. The chemical or enzymatic hydrolysis of fucose-rich polysaccharides offers a new efficient way to process fucose. The exopolysaccharide in question produces a solution of very low viscosity that shows pseudoplastic behavior and emulsifying activity on several hydrophobic substrates. It also has a high capacity for