Abstract
Bacteria on the surface of river sand grains were successively detached by changing the number and strength of washing procedures and then divided into different fractions. The ratio of slow-growing organisms in each fraction increased as the number of washings increased and intensified by sonication. The cells of these slow-growing strains were more hydrophobic, less negatively charged and had greater isoelectric point (IEP) values compared with fast-growing strains. The strains having greater IEP values attached more easily to a glass and a plastic surface than the strains having smaller IEP values. These findings lead to an assumption that the slow-growing bacteria have surface characteristics enabling the cells to attach more firmly to substrate surfaces.
