Ali, P.* ; Shah, A.A.* ; Hasan, F.* ; Hertkorn, N. ; Gonsior, M.* ; Sajjad, W.* ; Chen, F.*
     
    
        
A glacier bacterium produces high yield of cryoprotective exopolysaccharide.
    
    
        
    
    
        
        Front. Microbiol. 10:3096 (2020)
    
    
    
      
      
	
	    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.
	
	
	    
	
       
      
	
	    
		Impact Factor
		Scopus SNIP
		Web of Science
Times Cited
		Scopus
Cited By
		Altmetric
		
	     
	    
	 
       
      
     
    
        Publication type
        Article: Journal article
    
 
    
        Document type
        Scientific Article
    
 
    
        Thesis type
        
    
 
    
        Editors
        
    
    
        Keywords
        Cryopreservation ; Exopolysaccharide ; Glacier Bacteria ; Karakoram ; Psychrotrophs; Pseudomonas-aeruginosa; Sea-ice; Cold Adaptation; Extracellular Polysaccharides; Structural-characterization; Psychrophilic Bacterium; Antioxidant Activity; Antifreeze Protein; Freezing Tolerance; Low-temperature
    
 
    
        Keywords plus
        
    
 
    
    
        Language
        english
    
 
    
        Publication Year
        2020
    
 
    
        Prepublished in Year
        
    
 
    
        HGF-reported in Year
        2020
    
 
    
    
        ISSN (print) / ISBN
        1664-302X
    
 
    
        e-ISSN
        1664-302X
    
 
    
        ISBN
        
    
    
        Book Volume Title
        
    
 
    
        Conference Title
        
    
 
	
        Conference Date
        
    
     
	
        Conference Location
        
    
 
	
        Proceedings Title
        
    
 
     
	
    
        Quellenangaben
        
	    Volume: 10,  
	    Issue: ,  
	    Pages: ,  
	    Article Number: 3096 
	    Supplement: ,  
	
    
 
    
        
            Series
            
        
 
        
            Publisher
            Frontiers
        
 
        
            Publishing Place
            Avenue Du Tribunal Federal 34, Lausanne, Ch-1015, Switzerland
        
 
	
        
            Day of Oral Examination
            0000-00-00
        
 
        
            Advisor
            
        
 
        
            Referee
            
        
 
        
            Examiner
            
        
 
        
            Topic
            
        
 
	
        
            University
            
        
 
        
            University place
            
        
 
        
            Faculty
            
        
 
    
        
            Publication date
            0000-00-00
        
 
         
        
            Application date
            0000-00-00
        
 
        
            Patent owner
            
        
 
        
            Further owners
            
        
 
        
            Application country
            
        
 
        
            Patent priority
            
        
 
    
        Reviewing status
        Peer reviewed
    
 
     
    
        POF-Topic(s)
        30202 - Environmental Health
    
 
    
        Research field(s)
        Environmental Sciences
    
 
    
        PSP Element(s)
        G-504800-001
    
 
    
        Grants
        
    
 
    
        Copyright
        
    
 	
    
    
    
    
    
        Erfassungsdatum
        2020-03-26