Enhanced crude oil biodegradation and rhamnolipid production by Pseudomonas stutzeri strain G11 in the presence of Tween-80 and Triton X-100

WOS: 000261580800011PubMed ID: 19297982In 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 surfactant

Investigation of antimicrobial activity of some Turkish pleurocarpic mosses

WOS: 000298544000016In 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).Nigde University [FEB2010/35]The authors are indebted to the Research Fund of Nigde University for financial support (Project no: FEB2010/35)