Characterizing the new bacterial isolates of high yielding exopolysaccharides under hypersaline conditions

Isfahani, Faranak Moshabaki; Tahmourespour, Arezoo; Hoodaji, Mehran; Ataabadi, Mitra; Mohammadi, Abdorreza

doi:10.1016/j.jclepro.2018.03.030

Cited by 41 publications

(13 citation statements)

References 39 publications

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“…On the other hand, NaCl also affects EPS and other bacterial metabolites production. An increase in Na + generally results in increased bacterial EPS production, which in turn may enhance Na + chelation, and also change EPS composition [ 59 , 60 , 62 , 63 , 66 , 70 ]. For example, EPS carbohydrate and protein content increase with salinity.…”

Section: Salinitymentioning

confidence: 99%

The Effects of Plant-Associated Bacterial Exopolysaccharides on Plant Abiotic Stress Tolerance

2021

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Plant growth-promoting rhizobacteria (PGPR) are beneficial soil microorganisms that can stimulate plant growth and increase tolerance to biotic and abiotic stresses. Some PGPR are capable of secreting exopolysaccharides (EPS) to protect themselves and, consequently, their plant hosts against environmental fluctuations and other abiotic stresses such as drought, salinity, or heavy metal pollution. This review focuses on the enhancement of plant abiotic stress tolerance by bacterial EPS. We provide a comprehensive summary of the mechanisms through EPS to alleviate plant abiotic stress tolerance, including salinity, drought, temperature, and heavy metal toxicity. Finally, we discuss how these abiotic stresses may affect bacterial EPS production and its role during plant-microbe interactions.

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Section: Salinitymentioning

confidence: 99%

The Effects of Plant-Associated Bacterial Exopolysaccharides on Plant Abiotic Stress Tolerance

2021

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“…Many microorganisms including bacteria (Sardari et al, 2017), archaea (Squillaci et al, 2016), cyanobacteria (Bemal and Anil, 2017), fungi (Sun et al, 2016), yeast (Han et al, 2018), and microalgae (García-Cubero et al, 2018) are known to produce EPSs. EPS provides protection against the predators, antimicrobial agents and assist microorganisms to endure extremes of temperature (Casillo et al, 2017), salinity (Bemal and Anil, 2017;Isfahani et al, 2018), and desiccation (Tamaru et al, 2005;Knowles and Castenholz, 2008). EPSs are also essential for the attachment of microorganisms to other surfaces which may be biotic or abiotic (Janczarek et al, 2015), nutrient uptake (Kalpana et al, 2018), and most importantly in biofilm formation (Limoli et al, 2015;Rossi and De Philippis, 2015).…”

Section: Introductionmentioning

confidence: 99%

A Glacier Bacterium Produces High Yield of Cryoprotective Exopolysaccharide

et al. 2020

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Pseudomonas sp. BGI-2 is a psychrotrophic bacterium isolated from the ice sample collected from Batura glacier, Pakistan. This strain produces highly viscous colonies on agar media supplemented with glucose. In this study, we have optimized growth and production of exopolysaccharide (EPS) by the cold-adapted Pseudomonas sp. BGI-2 using different nutritional and environmental conditions. Pseudomonas sp. BGI-2 is able to grow in a wide range of temperatures (4-35 • C), pH (5-11), and salt concentrations (1-5%). Carbon utilization for growth and EPS production was extensively studied and we found that glucose, galactose, mannose, mannitol, and glycerol are the preferable carbon sources. The strain is also able to use sugar waste molasses as a growth substrate, an alternative for the relatively expensive sugars for large scale EPS production. Maximum EPS production was observed at 15 • C, pH 6, NaCl (10 g L −1), glucose as carbon source (100 g L −1), yeast extract as nitrogen source (10 g L −1), and glucose/yeast extract ratio (10/1). Under optimized conditions, EPS production was 2.01 g L −1 , which is relatively high for a Pseudomonas species compared to previous studies using the same method for quantification. High-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) analysis of EPS revealed glucose, galactose, and glucosamine as the main sugar monomers. Membrane protection assay using human RBCs revealed significant reduction in cell lysis (∼50%) in the presence of EPS, suggesting its role in membrane protection. The EPS (5%) also conferred significant cryoprotection for a mesophilic Escherichia coli k12 which was comparable to glycerol (20%). Also, improvement in lipid peroxidation inhibition (in vitro) resulted when lipids from the E. coli was pretreated with EPS. Increased EPS production at low temperatures, freeze thaw tolerance of the EPS producing strain, and increased survivability of E. coli in the presence of EPS as cryoprotective agent supports the hypothesis that EPS production is a strategy for survival in extremely cold environments such as the glacier ice.

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“…Some microorganisms can synthesize these biopolymers and secret them into the environment. EPS may vary in chemical composition, molecular weight, and therefore, in the functions, they have to depend on the environmental conditions, including salt concentration, carbon and nitrogen sources, pH, and temperature values (More et al 2014, Moshabaki et al 2018. These compounds would be naturally involved in intercellular communication, molecular recognition, biofilm formation, flocculation, adhesion, protective barrier for cells, water retention, and one more interesting feature to consider is that they are environmentally friendly, being one of their major advantages in comparison to traditional polymers (More et al 2014, Wang et al 2019.…”

Section: Extracellular Polymeric Compounds (Eps) Their Properties And...mentioning

confidence: 99%

“…As a general adaptation mechanism, cells that are subjected to environmental stresses counteract them by stimulating different pathways and synthesizing specific molecules, such as antioxidant enzymes, carotenoids, exopolymeric substances (EPS), or by producing biofilms and biosurfactants (Irazusta et al 2013, Fu et al 2014, Moraga et al 2017, Moshabaki et al 2018, Martínez et al 2019a). Many of the molecules produced by halophilic microorganisms are currently applied in biotechnological processes (Kumar et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Biotechnological potential of microorganisms isolated from the salar del hombre muerto, Argentina

LOPEZ

Martínez

Rajal

et al. 2023

An. Acad. Bras. Ciênc.

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Bacterial strains were isolated from soil and aqueous solution samples from the Salar del Hombre Muerto, Argentina. A total of 141 strains were characterized and the tolerance to sodium chloride was evaluated. We performed a screening to search for molecules of biotechnological interest: carotenoids (11%), emulsifiers (95%), and exopolysaccharides (6%), and to assess the production of enzymes, including proteolytic (39%), lipolytic (26%), hemolytic (50%), and catalase activities (99%); 25 bacterial strains were selected for further studies. Some of them produced biofilms, but only Bacillus sp.HA120b showed that ability in all the conditions assayed. Although 21 strains were able to form emulsions, the emulsifying index Kocuria sp. M9 and Bacillus sp. V3a cultures were greater than 50% and, emulsions were more stable when the bacteria grew in higher salt concentrations. Only pigmented Kocuria sp. M9 showed lipolytic activity on olive oil medium and was able to produce biofilms when cultured without and with 4 M of NaCl. Yellow pigments, lipase activity, and biosurfactant production were observed for Micrococcus sp. SX120. Summarizing, we found that the selected bacteria produced highly interesting molecules with diverse industrial applications and, many of them are functional in the presence of high salt concentrations.

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Characterizing the new bacterial isolates of high yielding exopolysaccharides under hypersaline conditions

Cited by 41 publications

References 39 publications

The Effects of Plant-Associated Bacterial Exopolysaccharides on Plant Abiotic Stress Tolerance

The Effects of Plant-Associated Bacterial Exopolysaccharides on Plant Abiotic Stress Tolerance

A Glacier Bacterium Produces High Yield of Cryoprotective Exopolysaccharide

Biotechnological potential of microorganisms isolated from the salar del hombre muerto, Argentina

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