Tazehkand Shiva S, Torkzaban Saeed, Bradford Scott A, Walker Sharon L
Dep. of Earth Sciences, Utrecht Univ., Utrecht, the Netherlands.
J Environ Qual. 2008 Oct 23;37(6):2108-15. doi: 10.2134/jeq2008.0023. Print 2008 Nov-Dec.
The effect of cell preparation methods on the surface chemistry and retention of Escherichia coli D21 g was investigated over a range of ionic strength conditions. The cell preparation methods that were considered included filtration and centrifugation (at various speeds and for different durations). For a given ionic strength condition, it was found that cells prepared by filtration were more negatively charged and hydrophobic than cells prepared by centrifugation. Increasing the centrifugation speed (force imposed) or duration produced cells with a higher zeta potential (less negative) and a lower hydrophobicity. Column transport experiments for E. coli D21 g were also conducted with ultra pure quartz sand and the same solution chemistries. The first-order retention rate coefficient for E. coli D21 g increased with increasing speed and duration of centrifugation, and was lowest in the case of filtered cells. Moreover, the influence of cell preparation method was more pronounced in lower ionic strength solutions.
