Anditalea andensis ANESC-ST--An Alkaliphilic Halotolerant Bacterium Capable of Electricity Generation under Alkaline-Saline Conditions

Effects of the presence of phosphate buffer solution on removal efficiency of Pb and Zn in soil by solid phase microbial fuel cells

Simple, effective and environment-friendly ways for remediating toxic metal pollution are necessary. In this study, the effect of different concentrations phosphate buffer solution (PBS) on removal efficiency of Pb and Zn in soil by solid phase microbial fuel cell (SMFC) was investigated. During 100 days of operation, the SMFC with 150 mM PBS generated the highest power density of 21.7 mW m^-2 and the lowest internal resistance of 161 Ω. The addition of PBS can also increase soil conductivity and maintain a suitable pH for microbial activity. Furthermore, the removal rate of Pb and Zn in the SMFC with 150 mM PBS can reach 14.7% and 22.3%, respectively. The microbial community analyses demonstrated that Anditalea as an exoelectrogen in alkaline-saline conditions was significantly enriched in the SMFC with 150 mM PBS. This study provides an effective strategy for strengthening SMFC to remove toxic metals in soil.

Halobacterium salinarum NRC-1 Sustains Voltage Production in a Dual-Chambered Closed Microbial Fuel Cell

Sustained bioenergy production from organisms that thrive in high salinity, low oxygen, and low nutrition levels is useful in monitoring hypersaline polluted environments. Microbial fuel cell (MFC) studies utilizing single species halophiles under salt concentrations higher than 1 M and as a closed microbial system are limited. The current study aimed to establish baseline voltage, current, and power density from a dual-chambered MFC utilizing the halophile Halobacterium salinarum NRC-1. MFC performance was determined with two different electrode sizes (5 cm² and 10 cm²), under oscillating and nonoscillating conditions, as well as in a stacked series. A closed dual-chamber MFC system of 100 mL capacity was devised with Halobacterium media (4.3 M salt concentration) as both anolyte and catholyte, with H. salinarum NRC-1 being the anodic organism. The MFC measured electrical output over 7, 14, 28, and 42 days. MFC output increased with 5 cm² sized electrodes under nonoscillating (p < 0.0001) relative to oscillating conditions. However, under oscillating conditions, doubling the electrode size increased MFC output significantly (p = 0.01). The stacked series MFC, with an electrode size of 10 cm², produced the highest power density (1.2672 mW/m²) over 14 days under oscillation. Our results highlight the potentiality of H. salinarum as a viable anodic organism to produce sustained voltage in a closed-MFC system.