کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
609720 880628 2010 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
A modified microbial adhesion to hydrocarbons assay to account for the presence of hydrocarbon droplets
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی شیمی کلوئیدی و سطحی
پیش نمایش صفحه اول مقاله
A modified microbial adhesion to hydrocarbons assay to account for the presence of hydrocarbon droplets
چکیده انگلیسی

The microbial adhesion to hydrocarbons (MATH) assay has been used widely to characterize microbial cell hydrophobicity and/or the extent of cell adhesion to hydrophobic liquids. The classical MATH assay involves spectrophotometric absorbance measurements of the initial and final cell concentrations in an aqueous cell suspension that has been contacted with a hydrocarbon liquid. In this study, microscopic examination of the aqueous cell suspension after contact with hexadecane or a hexadecane/toluene mixture revealed the presence of hydrocarbon droplets. The hydrocarbon droplets contributed to the absorbance values during spectrophotometric measurements and caused erroneous estimates of cell concentrations and extents of microbial adhesion. A modified MATH assay that avoids such artefacts is proposed here. In this modified assay, microscopic examination of the aqueous suspension and direct cell counts provides cell concentrations that are free of interference from hydrocarbon droplets. The presence of hydrocarbon droplets was noted in MATH assays performed with three bacterial strains, and two different hydrocarbons, at ionic strengths of 0.2 mM and 20 mM and pH 6. In these experiments, the formation of quasi-stable hydrocarbon droplets cannot be attributed to the presence of biosurfactants, or stabilization by biocolloids. The presence of surface potential at the hydrocarbon–water interface that was characterized by electrophoretic mobility of up to −1 and −2 μm cm/Vs, likely caused the formation of the quasi-stable hydrocarbon droplets that provided erroneous results using the classical MATH assay.

Hydrocarbon droplets confound spectrophotometric assessments of concentrations of non-adhered cells in the microbial adhesion to hydrocarbons assay. Use of a Helber cell counting chamber allows reliable measurements of the number of non-adhered cells.Figure optionsDownload high-quality image (107 K)Download as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Colloid and Interface Science - Volume 344, Issue 2, 15 April 2010, Pages 492–496
نویسندگان
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