The identified compounds of root exudates from <i>S. alfredii</i>.

The identified compounds of root exudates from S. alfredii.</p

Sample scores for the first (PC1) and second (PC2) principal components from the principal component analysis for identified root exudates from <i>S. alfredii</i>.

Sample scores for the first (PC1) and second (PC2) principal components from the principal component analysis for identified root exudates from S. alfredii.</p

Relationships of pulsed frequency and anammox bacteria growth rate, at low temperatures

This study explored pulsed frequency that could enhance the anammox bacteria growth rate and TN removal rate at low temperatures (16 ± 1°C). The results showed that the growth rate of anammox bacteria in R1 (1000 Hz) was significantly higher than in R2 (30 Hz) and R3 (106Hz). The relative abundance values of anammox bacteria R1 were higher by 52.21% and 172.41% than R2 and R3, while that of MLSS were as high as 241.07% and 471.36% than R2 and R3, with the nitrogen loading rate was 6.84 kg-N/m³/d. Besides, the dynamics also showed that the specific anammox activity (SAA) and the cellular yield of R1 were higher than R2 and R3. The intermediate frequency could enhance the cell division by stimulating the anammoxosome and reduce the ionic hydration layer to accelerate the ion migration rate, further improving the number of anammox bacteria even at low temperatures. The pulsed frequency could enhance the anammox growth rate and the doubling time is just 5 d.</p

Sample scores of the orthogonal partial least-squares discrimination analysis for identified root exudates from <i>S. alfredii</i>.

Sample scores of the orthogonal partial least-squares discrimination analysis for identified root exudates from S. alfredii.</p

Repeatability of the data.

<p>Repeatability of the data.</p

Changes in dry weights, Cd concentrations and Cd accumulation in various tissues of <i>S. alfredii</i> with exposure to supplying Cd levels for 4 days.

<p>Changes in dry weights, Cd concentrations and Cd accumulation in various tissues of <i>S. alfredii</i> with exposure to supplying Cd levels for 4 days.</p

The variation of identified root exudates that caused the separation among the different Cd exposed concentrations.

<p>The variation of identified root exudates that caused the separation among the different Cd exposed concentrations.</p

Loadings plot of identified root exudates from <i>S. alfredii</i> for the OPLS-DA model.

<p>Loadings plot of identified root exudates from <i>S. alfredii</i> for the OPLS-DA model.</p

Pulsed electric field enhanced <i>Bacillus</i> sp. DL4 biodegradation of Triclosan: Focusing on operational performance and metabolomic analysis

Electrochemical-assisted microbial degradation technology was considered a crucial strategy to reduce micropollutants, but the mechanism of the pulsed electric field (PEF) in affecting biodegradation had not been systematically studied. This study aimed to construct a bio-electrochemical system (BES) using PEF to investigate its effect on the degradation of triclosan (TCS) by the aerobic bacterium Bacillus sp. DL4. The operating optimal parameters for the BES (i.e., 0.01 A of the pulsed current, 1000 Hz of the pulse frequency, Fe (+) - C (-) of the plate materials, 4 cm of the plate spacing) were obtained by batch experiments. The maximum biomass (OD600 = 1.0 ± 0.05) was achieved and the removal efficiency of TCS reached above 95% in 24 h under the obtained operating conditions. Meanwhile, a thorough and methodical investigation of the metabolites in strain DL4 stimulated by PEF using untargeted Liquid Chromatography - Mass Spectrometry (LC-MS). In multivariate analysis, the experimental groups showed a notable separation in Principal Components Analysis (PCA) and Orthogonal Partial Least Squares Analysis discriminant analysis (OPLS-DA) score plots. A total of 3181 differential metabolites were obtained, and the up-regulated metabolites were mainly related to “Aminoacyl-tRNA biosynthesis”, “Arginine and proline metabolism”, “Lysine degradation”, “ABC transporters”, and “TCA cycle”, implying that PEF enhanced the degradation efficiency of TCS by enriching functional genes with transport ability and ion migration ability in cells. This study illuminated how PEF can affect TCS biodegradation and gives insights into the application prospect of electrochemical-assisted biodegradation technology in water environment treatment.</p