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    Characterization and production of the exopolysaccharide (EPS) from Pseudomonas aeruginosa G1 and Pseudomonas putida G12 strains
    (ELSEVIER SCI LTD, 2008) Celik, Gokcen Yuvali; Aslim, Belma; Beyatli, Yavuz
    In this study, exopolysaccharides (EPSs) production was investigated by growing strains of Pseudomonas aeruginosa G1 and Pseudomonas putida G12 in medium containing various carbon sources such as glucose, mannose, fructose, and xylose. EPS production (192 and 182 mg/L, respectively) of these strains grown in PAP medium with 2% glycerol (v/v) was used as control. The highest EPS production of the two strains was found in the xylose containing medium. The effect of different concentrations [2-6% (w/v)] of xylose on EPS production of both strains was also studied. The maximum EPS yield (368 mg/l(-1)) of the strain G1 was recorded in 3% (w/v) xylose, while the highest yield EPS yield (262 mg/L(-1)) of the strain G 12 was recorded in 2% (w/v) xylose. The monosaccharide compositions of EPS produced by the two strains were analyzed by HPLC. Strain G1 [2% (w/v) glycerol] was found to compose of neutral sugars (92.0%), acetylated amino sugars (8.0%), while strain G1 [3% (w/v) xylose] contained neutral sugars (99.2%), acetylated amino sugars (0.8%). However, the composition of strain G12 [2% (w/v) glycerol] was neutral sugars (96.8%), acetylated amino sugars (3.2%) and the strain G12 [2% (w/v) xylose] was found to contain neutral sugars (96.1%), acetylated amino sugars (3.9%). (C) 2007 Elsevier Ltd. All rights reserved.
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    Enhanced crude oil biodegradation and rhamnolipid production by Pseudomonas stutzeri strain G11 in the presence of Tween-80 and Triton X-100
    (TRIVENI ENTERPRISES, 2008) Celik, Gokcen Yuvali; Aslim, Belma; Beyatli, Yavuz
    In this study, the growth of sixty-one bacterial strains in crude oil were determined spectrophotometrically at 620 nm. Pseudomonas aeruginosa G11 Pseudomonas fluorescens G6, Pseudomonas stutzeri G11 and Pseudomonas putida G15 were chosen for the study based on the efficiency of crude oil utilisation. At 1%(v/v) crude oil concentration, P. stutzeri G11 strain degraded a maximum of 69%. The percentage of degradation by the P. stutzeri G11 strain decreased from 69% to 59% as the concentration of crude oil was increased from 1% (v/v) to 2.5% (v/v). Strain G11 was selected to determine the effects of surfactants(Tween-80 and TritonX-100) on the biodegradation of crude oil. While strain G11 showed 76% degradation at mineral salts medium (MSM) containing 1% (v/v) crude oil + 1% (vlv) TritonX-100, it showed 61% degradation at MSM containing 2.5% (6) crude oil + 2.5% (v/v)TritonX-100. Also, degradation rate of this strain was 96% in the presence of 1% (v/v) crude oil + 1% (v/v) Tween-80, while degradation rate was 48% in the presence of 2.5% (v/v) crude oil + 2.5% (v/v) Tween-80. Additionally, we investigated the rhamnolipid production of P. stutzeri G11 strain both in crude oil and in crude oil + two different surfactants (TritonX-100 and Tween-80, separately), These results suggest that surfactants have improved both crude oil degradation and rhamnolipid production and the degradation rates have depended very much on the chemical structure of surfactants
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    Influence of Carbon Sources on The Production and Characterization of The Exopolysaccharide (EPS) by Bacillus sphaericus 7055 Strain
    (SPRINGER/PLENUM PUBLISHERS, 2012) Yilmaz, Murat; Celik, Gokcen Yuvali; Aslim, Belma; Onbasili, Dilsad
    In this study, EPS produced by five Bacillus spp. strains was determined. The only one strain (B. sphaericus 7055) was selected due to its high EPS production and it was investigated by growing this strain in LB broth medium containing various carbon sources. The highest EPS production of this strain was found in medium containing fructose. However, the effect of different concentrations of fructose and molasses on EPS production by the strain was studied. The maximum EPS yield of the strain 7055 was recorded with 2.5% (w/v) fructose, also the highest EPS production was found in 2.5% (w/v) molasses. The strain 7055 was found to contain (98.6%) galactose and (1.4%) glucuronic acid in control medium whereas the composition of the strain 7055 (2.5% (w/v) fructose) was found to be (99.9%) neutral sugar and (0.1%) Glucuronic acid while the strain 7055 (2.5% (w/v) molasses) was found to contain (65.9%), neutral sugars and (34.1%) glucuronic acid.
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    Investigation of antimicrobial activity of some Turkish pleurocarpic mosses
    (ACADEMIC JOURNALS, 2011) Colak, Emel; Kara, Recep; Ezer, Tulay; Celik, Gokcen Yuvali; Elibol, Busra
    In this study, the antimicrobial activities of different extracts from the five pleurocarpic mosses (Platyhypnidium riparioides (Hedw.) Dixon, Leucodon sciuroides (Hedw.) Schwagr., Hypnum cupressiforme Hedw., Homalothecium sericeum (Hedw.) Br.Eur., and Anomodon viticulosus (Hedw.) Hook & Taylor.) were tested aganist eight bacterial and fungal strains. For the extraction, four different solvents (ethyl alcohol, methyl alcohol, chloroform and acetone) were used. While methanolic extracts of P. riparioides showed the highest antibacterial effect against the Gram-negative bacterium Pseudomonas aeroginosa ATCC 27853, acetone extract of A. viticulosus showed the highest antifungal effect against the fungus Saccharomyces cerevisiae ATCC. All the results were compared with standard antibiotic discs: ketoconazole (50 mu g), amphicillin (10 mu g), eritromycin (15 mu g), penicillin (10 mu g) and vancomycin (30 mu g).
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    Relationship between heavy metals resistance and exopolysaccharide (EPS) synthesis of Pseudomonas spp. strains
    (PARLAR SCIENTIFIC PUBLICATIONS (P S P), 2007) Celik, Gokcen Yuvali; Aslim, Belma; Beyatli, Yavuz
    In this study, we determined the resistance to heavy metals (Zn2+ and Cd2+) and exopolysaccharide (EPS) production by 15 Pseudomonas spp. EPS yields from these strains ranged between 22-192 mg l(-1). In addition, EPS production rates of two strains (G I and G 12), selected on the basis of their high EPS production (192 and 182 mg l(-1), respectively), but also heavy metal resistance, were determined in the presence of Zn2+ (10-40 mM) and Cd2+ (5-20 mM). There was a general increase in EPS production by both strains with increasing heavy metal concentrations. G12 strain showed an increase (approx. 6-fold) in the extent of EPS produced on Pseudomonas Agar P (Difco) medium, supplemented with 2% (v/v) glycerol containing 40 mM Zn2+. By contrast, G1 strain exhibited a lower increase than G12 strain. Furthermore, G12 and G1 strains showed an identical increase (approx. 2-fold) in EPS production on Pseudomonas Agar P (Difco) medium, when supplemented with 2% (v/v) glycerol containing 20 mM Cd2+.