Application of Saccharomyces cerevisiae yeast in biofuel cells

Abstract

With the rapid growth of research into the performance and applicability of biofuel cells, a remaining crucial factor is ensuring their efficiency and increasing the current output and power relative to the fuel cell area. To improve the efficiency indicators, many new scientific tasks have to be solved, such as improving the charge transfer by selecting materials and examining their impact on the performance of the biofuel cell and the viability of the microorganisms. To create and investigate a microbial fuel cell by modifying its anodic part and using yeast as a catalyst, theoretical and analytical studies were first performed to elucidate the primary data useful for research and find solutions to the problem examined in previous studies. Experimental studies were also performed with the yeast Saccharomyces cerevisiae modified with 9,10-phenanthrenequinone (PQ), 2-methyl-1,4-naphthoquinone (MD) quinones, and multilayer carbon nanotubes. The investigation and evaluation focused on the viability of different yeasts under the influence of redox mediators and multi-walled carbon nanotubes (MW-CNTs). Electrochemical properties were investigated by cyclic voltammetry, and the local electrochemical properties were examined by scanning electrochemical microscopy (SECM). Mechanical properties were studied by atomic force microscopy. To this end, an atomic force microscopy model was developed to evaluate the image quality of the test results and to determine the artefacts, considering the tip geometry, scanning speed, and sample material. Investigations of the developed biofuel cells were performed at thirteen different load resistances, measuring the voltage and calculating the generated power. All the obtained data were analysed at the end of the work, and conclusions with recommendations were presented. The obtained research results expand research possibilities and the use of biofuel cells. The study on applying yeast Saccharomyces cerevisiae in biofuel cells reveals the opportunities of redox medium immobilisation, the efficiency of new materials applied in biofuel cells and the benefits of selecting the parameters of the atomic force microscope used for research. Using the developed atomic force microscopy model and setting the scan parameters, the image quality of any cell can be determined before measurement if the surface material and structure are known. The atomic force microscope (AFM) operator can enter the parameters of the model surface structure and select the optimal scanning speed and the most reliable interaction force. In addition, the results determined by the AFM can be compared with the theoretically calculated from the proposed model. Also, in this research, the presented methods of applying redox mediators in biofuel cells can increase the efficiency of future biofuel cells.