Electroactive biofilm development on carbon fiber anode by Pichia fermentans in a wheat straw hydrolysate based microbial fuel cell

Abstract

Abundantly available lignocellulosic biomass may be used as feed stock for various applications including microbial fuel cells. However, a pre-treatment of such biomass is always required for an efficient operation. In the present study, a double-chambered fuel cell was developed to evaluate the biofilm formation along with electricity production ability of Pichia fermentans using wheat straw hydrolysate. The wheat straw hydrolysate was prepared by degrading the wheat straw using white rot fungi, Phlebia brevispora, Phanerochaete chrysosporium, and Phlebia floridensis. This hydrolysate primarily consisted of sugars, protein, phenols, and enzymes and used as anolyte in fuel cell. The hydrolysate as anolyte facilitated the growth of yeast Pichia fermentans and development of biofilm. Maximum electrochemical response of 20.13 ± 0.052 mW m−2 and 20.42 ± 0.071 mW m−2 was recorded in hydrolysate prepared by using P. floridensis and P. chrysosporium, respectively. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) of the biofilm revealed the typical characteristics along with significant exopolysaccharide (EPS) production. The study demonstrated active biofilm formation by yeast using wheat straw hydrolysate, which further indicates the application of such organisms in the development of lignocellulosic biomass based systems including the electrochemical one.