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Electrochemical Communication Between Electrodes and Rhodobacter capsulatus Grown in Different Metabolic Modes
Author(s) -
Hasan Kamrul,
Reddy Kesava Vijalapuram Raghava,
Eßmann Vera,
Górecki Kamil,
Conghaile Peter Ó,
Schuhmann Wolfgang,
Leech Dónal,
Hägerhäll Cecilia,
Gorton Lo
Publication year - 2015
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.201400456
Subject(s) - rhodobacter , microbial fuel cell , photocurrent , electron transfer , electrode , electrochemistry , redox , materials science , graphite , chemistry , chemical engineering , optoelectronics , photochemistry , inorganic chemistry , biochemistry , anode , organic chemistry , mutant , gene , engineering
The majority of efforts on microbial and photosynthetic microbial fuel cells are both curiosity driven and made to possibly meet the future growing demand for sustainable energy. The most metabolically versatile purple bacteria Rhodobacter capsulatus is a potential candidate for this purpose. However, utilizing bacteria in such systems requires efficient electronic transfer communication between the microbial cells and the electrodes, which is one of the greatest challenges. Previous studies demonstrated that osmium redox polymers (ORPs) could be used for extracellular electron transfer between the cells and electrodes. Recently, heterotrophically grown R. capsulatus has been wired with ORP modified electrodes. Here in this communication, we report electron transfer from R. capsulatus grown under heterotrophic as well as under photoheterotrophic conditions to electrodes. The cells, immobilized on bare graphite and ORP modified graphite electrodes, were excited with visible light and subsequent photosynthetic electron transfer was recorded using cyclic voltammetric and chronoamperometric measurements. Photoheterotrophically grown R. capsulatus cells on bare graphite generate a significant photocurrent density of 3.46 µA cm −2 , whereas on an ORP modified electrode the current density increases to 8.46 µA cm −2 . Furthermore, when 1 mM p‐ benzoquinone is added to the electrolyte the photocurrent density reaches 12.25 µA cm −2 . Our results could have significant implications in photosynthetic energy conversion and in development of photobioelectrochemical devices.