Electricity generation from terephthalic acid using a microbial fuel cell

BACKGROUND: Pure terephthalic acid (PTA) is a petrochemical product of global importance and is widely applied as an important raw material in making polyester fiber and polyethylene terephthalate (PET) bottles. In this work, a single-chamber microbial fuel cell (MFC) was constructed using terephthalic acid (TA) with a chemical oxygen demand (COD) concentration range from 500 mg L-1 to 3500 mg L-1 as the electron donor and strain PA-18 as the biocatalyst. RESLUTS: In the single chamber MFC, several factors were examined to determine their effects on power output, including COD concentration and electrode spacing. The characteristic of the strain PA-18 was further studied. Cyclic voltammetry showed that electrons were directly transferred onto the anode by bacteria in biofilms, rather than self-produced mediators of bacteria in the solutions. Scanning electron microscopy (SEM) observation showed that the anodic electrode surface was covered by bacteria which were responsible for electron transfer. Direct 16s-rDNA analysis showed that the PA-18 bacteria shared 99% 16SrDNA sequence homology with Pseudomonas sp. CONCLUSIONS: Electricity generation from TA in MFC was observed for the first time. The maximum power density produced by TA was 160 mW m(-2), lower than that achieved using domestic wastewater. This novel technology provided an economical route for electricity energy recovery in PTA wastewater treatment. High internal resistance was the major limitation. To further improve the power output, the electron transfer rate was accelerated by overexpression of membrane the protein gene of the strain PA-18 and by reducing the electrolyte and mass transfer resistance by optimizing reactor configuration. (C) 2008 Society of Chemical Industry