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A mediatorless microbial fuel cell based on the direct biocatalysis of Escherichia coli shows significantly enhanced performance by using bacteria electrochemically-evolved in fuel cell environments through a natural selection process and a carbon/PTFE composite anode with an optimized PTFE content.

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Aims To investigate the phenanthrene‐degrading abilities of the halophilic Martelella species AD‐3 under different conditions and to propose a possible metabolic pathway. Methods and Results Using HPLC and GC‐MS analyses, the phenanthrene‐degrading properties of the halophilic strain AD‐3 and its metabolites were analysed. This isolate efficiently degraded phenanthrene under multiple conditions characterized by different concentrations of phenanthrene (100–400 mg l−1), a broad range of salinities (0·1–15%) and varying pHs (6·0–10·0). Phenanthrene (200 mg l−1) was completely depleted under 3% salinity and a pH of 9·0 within 6 days. The potential toxicity of phenanthrene and its generated metabolites towards the bacterium Vibrio fischeri was significantly reduced 10 days after the bioassay. On the basis of the identified metabolites, enzyme activities and the utilization of probable intermediates, phenanthrene degradation by strain AD‐3 was proposed in two distinct routes. In route I, metabolism of phenanthrene was initiated by the dioxygenation at C‐3,4 via 1‐hydroxy‐2‐naphthoic acid, 1‐naphthol, salicylic acid and gentisic acid. In route II, phenanthrene was metabolized to 9‐phenanthrol and 9,10‐phenanthrenequinone. Further study indicated that strain AD‐3 exhibited a wide spectrum of substrate utilization including other polycyclic aromatic hydrocarbons (PAHs). Conclusions The results suggest that strain AD‐3 possesses a high phenanthrene biodegradability and that the degradation occurs via two routes that remarkably reduce toxicity. Significance and Impact of the Study To the best of our knowledge, this work presents the first report of phenanthrene degradation by a halophilic PAH‐degrading strain via two routes. In the future, the use of halophilic strain AD‐3 provides a potential application for efficient PAH‐contaminated hypersaline field remediation.

A 2D sandwich-like TiO-rGO composite was fabricated by the Pickering emulsion approach to improve the photocatalytic efficiency. Through an in situ growth of antase-TiO nanoparticles on the interface of O/W type GO Pickering emulsion, TiO nanoparticles were closely and densely packed on the surface of well-exfoliated rGO sheets; meanwhile, many mesoporous voids acting as the adsorption chamber and microreactor were produced. Evaluated by methylene blue (MB) degradation, its photocatalytic activity was prominent compared with the common TiO-based photocatalyst, with the rate constants 5 and 3.1 times higher under visible light and xenon lamp, respectively. When we applied it in the photocatalytic degradation of tetracycline hydrochloride (TCH, such as 10 ppm) under the visible light without adding any oxidants, the total removal efficiency was as high as 94% after 40 min. The mechanism of this good photocatalytic efficiency was illustrated by the scavenger trapping tests, which showed that this unique structure of TiO-rGO composite induced by the Pickering emulsion can significantly enhance the light absorption ability, accelerate the separation rate of electron-hole pairs, increase the adsorption capacity of organic pollutants, and hence improve the photocatalytic efficiency.

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