Electrochemical activity of polypyrrole modified saccharomyces cerevisiae

Abstract

As we strive to find new ecologically friendlier sources of energy, alternative sources such as Microbial Fuel Cells (MFC) have grown in interest. Biofuel cells are bioelectrochemical systems which convert chemical energy into an electric current by using biological components e.g. living cells. In this research, we examine the effects of modifying Saccharomyces cerevisiae (S.cerevisiae) with a conducting polymer - polypyrrole [1] for the use in electrochemical systems e.g. biosensors, MFC. The synthesis of polypyrrole was induced by biochemical processes present in living S. cerevisiae and formed a layer within the cell‟s wall. A double mediator system with a hydrophilic and a lipophilic substance [2] ensured the charge transfer between the cell‟s cytoplasm and the extracellular medium. For investigating the changes due to encapsulation three techniques were employed: firstly, amperometric measurements at constant potential, secondly, scanning electrochemical microscopy [3] and finally atomic force microscopy. The last technique provided insight about the morphological changes and physical properties of S.cerevisiae, the other two techniques contributed to the bioelectrochemical activity evaluation.