Complete Genome Sequence of Pseudomonas Stutzeri S116 Provides Insights into the Mechanism of Microbial Fuel Cells

To identify suitable biocatalysts applied in microbial fuel cells (MFCs), Pseudomonas stutzeri S116 isolated from marine sludge was investigated, which possessed excellcent bioelectricity generation ability (BGA). Herein, P. stutzeri as a bioanode and biocathode achieved maximum output voltage (254.2 mV and 226.0 mV), and power density of (765 mW/m2 and 656.6 mW/m2). Complete genome sequencing of P. stutzeri was performed to reveal its potential microbial functions. The results exhibited that the strain was the ecologically dominant Pseudomonas, and its primary annotations were associated with energy production and conversion (6.84%), amino acid transport and metabolism (6.82%) and inorganic ion transport and metabolism (6.77%). The thirty-six genes involved in oxidative phosphorylation indicate that strain possesses an integrated electron transport chain. Moreover, many genes encoding redox mediators (mainly riboflavin and phenazine) were detected in the databases. Simultaneously, thiosulfate oxidization and dissimilatory nitrate reduction were annotated in the sulfur metabolism and nitrogen metabolism pathway. Gene function and cyclic voltammetry (CV) analysis indicated BGA of P. stutzeri probably was attributed to its cytochrome c and redox mediators, which enhance extracellular electron transfer (EET) rate.

Identification of a MarineBacillusStrain C5 and Parathion-Methyl Degradation Characteristics of the Extracellular Esterase B1

A bacterial strain C5 that can produce new type of marine esterase was isolated and screened from marine sludge. According to 16S rRNA sequence analysis and physiological and biochemical experiments, the strain was identified asBacillus subtilis. A single isozyme with a molecular weight of 86 kDa was observed by SDS-PAGE and native-PAGE. On this basis, the mechanism of esterase B1 secreted by strain C5 degrading parathion-methyl was explored, and the effects of temperature and pH on the degradation rate were investigated. From the results,p-nitrophenol was one of the degradation products of B1 degrading parathion-methyl, and the best degradation effect could be achieved at the temperature of 40°C and the neutral pH value.