INFLUENCE OF OXYGEN LIMITATION ON THE CELL-SURFACE PROPERTIES OF BACTERIA FROM ACTIVATED-SLUDGE

Cell surface hydrophobicity is believed to be important to flocculatio n in activated sludge and biofilm systems. Optimization of these proce sses includes changes in the growth conditions of the bacteria. A numb er of factors influence cell surface hydrophobicity. The influence of oxygen on the cell surface hydrophobicity of 4 bacteria isolated from activated sludge was tested. The bacteria were grown in batch cultures with and without oxygen limitation. It was found that oxygen limitati on generally caused a lowering of the cell surface hydrophobicity. The study also showed that there are many difficulties in measuring cell surface hydrophobicity since other cell surface properties, such as su rface charge. influence the measurement methods. The MATH test was emp loyed to establish how assay conditions influenced the results. (C) 19 98 IAWQ. Published by Elsevier Science Ltd.