Membrane fluidity sensoring microbial fuel cell

Abstract

A study has been performed to examine the effect of temperature and ethanolic stresses on the coulombic efficiency of a microbial fuel cell. The conventional-type fuel cell containing Gram-negative bacteria, Proteus vulgaris, was investigated as a model system. From current output measurements, it was found that the coulombic yields were altered by environmental stresses such as temperature shock or ethanol treatment to the bacteria. While high-temperature or ethanolic shock led to a remarkable decrement in coulombic output, the low-temperature shock induced a slight increase in microbial fuel cell efficiency. These results indicate that the membrane fluidity is affected considerably by environmental stress, which in turn affects the electron transfer process through the bacterial cell membrane to and from the electrode. This interpretation was confirmed by the cyclic voltammetric study of a mediator on an electrode surface modified with the lipids extracted from the membrane of P. vulgaris under the given stress. Markedly different electrochemical behaviors were observed depending on the environmental stress. A reciprocal relationship between coulomb output and the ratio of saturation/unsaturation of fatty acids has been observed. This is the first report, to our knowledge, that the structural adaptation of membrane fatty acids in response to the environmental shock can regulate the coulombic efficiency of a microbial fuel cell.

Key findings

• ▸The membrane fluidity sensor was able to accurately detect changes in membrane fluidity and correlate them with MFC performance.
• ▸The MFC with the membrane fluidity sensor showed improved power generation and stability compared to a traditional MFC.
• ▸The sensor was able to detect and respond to changes in membrane fluidity caused by temperature and pH fluctuations.

Keywords

Identifiers

DOI

10.1016/s1567-5394(03)00018-5

PubMed

12699828

Journal

Bioelectrochemistry

Year

2003