Selective adsorption of l-serine functional groups on the anatase TiO2(101) surface in benthic microbial fuel cells

• Published in: Physical chemistry chemical physics : PCCP 2014-10, Vol.16 (38), p.286-2817
• Main Authors: Zhao, Yan-Ling, Wang, Cui-Hong, Zhai, Ying, Zhang, Rui-Qin, Van Hove, Michel A
• Format: Article
• Language: English
• Subjects: Adsorption; Bacterial Physiological Phenomena; Bioelectric Energy Sources - microbiology; Computer Simulation; Computer-Aided Design; Electrodes - microbiology; Energy Transfer; Equipment Design; Equipment Failure Analysis; Models, Biological; Models, Chemical; Serine - chemistry; Surface Properties; Titanium - chemistry
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c4cp01891e

To help design bacteria-friendly anodes for unmediated benthic microbial fuel cells (MFCs), we explore the role of anatase TiO 2 (101) surface biocompatibility in selecting the functional groups of the levo-isomer serine ( l -Ser), which contains carboxyl, hydroxyl, and amino groups in a single molecule. By performing total energy calculations and molecular dynamics simulations based on a density-functional tight-binding method, we find that at room temperature, the surface should be active for biomolecules with carboxyl/carboxylic and hydroxyl groups, but it is not sensitive to those with amino groups. The hydrogen bonding between the hydroxyl H and surface O facilitates electron transfer from the pili or the bacterial matrix to the anode surface, which improves the output power density. Thus, in combination with conductive polymers, the anatase TiO 2 (101) surface can be an effective biocompatible substrate in benthic MFCs by enabling the surface O to form more hydrogen bonds with the hydroxyl H of the biomolecule. In unmediated benthic microbial fuel cells, the titania anode surface as a promising candidate can have effective interactions with the carboxylic and hydroxyl groups of bacteria or pili.