Adhesion of algal cells to surfaces

Abstract

This paper reports the cell–substratum interactions of planktonic (Chlorella vulgaris) and benthic (Botryococcus sudeticus) freshwater green algae with hydrophilic (glass) and hydrophobic (indium tin oxide) substrata to determine the critical parameters controlling the adhesion of algal cells to surfaces. The surface properties of the algae and substrata were quantified by measuring contact angle, electrophoretic mobility, and streaming potential. Using these data, the cell–substratum interactions were modeled using thermodynamic, DLVO, and XDLVO approaches. Finally, the rate of attachment and the strength of adhesion of the algal cells were quantified using a parallel-plate flow chamber. The results indicated that (1) acid–base interactions played a critical role in the adhesion of algae, (2) the hydrophobic alga attached at a higher density and with a higher strength of adhesion on both substrata, and (3) the XDLVO model was the most accurate in predicting the density of cells and their strength of adhesion. These results can be used to select substrata to promote/inhibit the adhesion of algal cells to surfaces.

Keywords:

• algae
• adhesion
• biofilm
• biofouling
• benthic
• XDVLO

Acknowledgments

This study is based upon work supported by the National Science Foundation under Grant No. CBET-1125755. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. The authors would like to thank Onur Taylan for his assistance with Labview and Geoff Geise for his assistance with surface potential measurements for glass and ITO.