Optimization of operating parameters for 2,5-furandicarboxylic acid recovery using electrodialysis with bipolar membrane and traditional electrodialysis systems.

Electrodialysis (ED) is an eco-friendly and feasible method to separate or recover ionic compounds by electric field attraction and configuration of ion exchange membranes. Strain Burkholderia sp. H-2 could biotransform 5-hydroxymethylfurfural (5-HMF) into a green platform compound, 2,5-furandicarboxylic acid (FDCA), using a bioreactor system. In this study, electrodialysis with the bipolar membrane (EDBM) and traditional ED systems were applied to recover and concentrate FDCA. Artificial and real FDCA effluents of the 5-HMF biotransformation bioreactor were used as the feedstock to establish the optimal conditions for FDCA recovery. The optimal FDCA concentration and pH of the artificial FDCA effluent were 2100 mg/L and 5, respectively. The suitable current density of the EDBM was 8.93 mA/cm2. For FDCA recovery and concentration using the ED, the feedstock volume and FDCA concentration in the concentration chamber were 1.5 L and 1000 mg/L, respectively. The FDCA recovery efficiency of the real FDCA effluent was 55.6 %. Suppose the pretreatment procedure of the real bioreactor effluent is further optimized. It is believed to benefit the enhancement of FDCA recovery efficiency and reduce energy consumption.

Deep-sea turbulence evolution observed by multiple closely spaced instruments.

Turbulent mixing in the deep ocean is not well understood. The breaking of internal waves on sloped seafloor topography can generate deep-sea turbulence. However, it is difficult to measure turbulence comprehensively due to its multi-scale processes, in addition to flow-flow and flow-topography interactions. Dense, high-resolution spatiotemporal coverage of observations may help shed light on turbulence evolution. Here, we present turbulence observations from four broadband ocean bottom seismometers (OBSs) and a 200-m vertical thermistor string (T-string) in a footprint of 1 × 1 km to characterize turbulence induced by internal waves at a depth of 3000 m on a Pacific continental slope. Correlating the OBS-calculated time derivative of kinetic energy and the T-string-calculated turbulent kinetic energy dissipation rate, we propose that the OBS-detected signals were induced by near-seafloor turbulence. Strong disturbances were detected during a typhoon period, suggesting large-scale inertial waves breaking with upslope transport speeds of 0.2-0.5 m s-1. Disturbances were mostly excited on the downslope side of the array where the internal waves from the Pacific Ocean broke initially and the turbulence oscillated between < 1 km small-scale ridges. Such small-scale topography caused varying turbulence-induced signals due to localized waves breaking. Arrayed OBSs can provide complementary observations to characterize deep-sea turbulence.

Tracking deep-sea internal wave propagation with a differential pressure gauge array.

Temperature is used to trace ocean density variations, and reveals internal waves and turbulent motions in the deep ocean, called 'internal motions.' Ambient temperature detected by geophysical differential pressure gauges (DPGs) may provide year-long, complementary observations. Here, we use data from four DPGs fixed on the ocean bottom and a high-resolution temperature sensor (T-sensor) 13 m above the seafloor as a square-kilometer array deployed offshore ~ 50 km east of Taiwan facing the open Pacific Ocean to examine the impact of temperature on DPG signals related to internal motions. The DPG signals correlate with T-sensor temperature variations between 0.002 and 0.1 mHz, but have time shifts partially caused by slow thermal conduction from the ambient seafloor to the DPG chamber and partially by internal motion propagation time across the array. Applying beamforming-frequency-wavenumber analysis and linear regression to the arrayed T-sensor and DPG data, we estimate the propagating slowness of the internal motions to be between 0.5 and 7.4 s m-1 from the northwest and northeast quadrants of the array. The thermal relaxation time of the DPGs is within 103-104 s. This work shows that a systematic scan of DPG data at frequencies < 0.1 mHz may help shed light on patterns of internal wave propagation in the deep ocean, especially in multi-scale arrays.

Evaluation use of bioaugmentation and biostimulation to improve degradation of sulfolane in artificial groundwater.

Column systems were used to evaluate the effectiveness of different bioremediation methods (biostimulation (BS) and bioaugmentation (BA)) in treating sulfolane-contaminated groundwater. Batch test results confirmed that Cupriavidus sp. Y9 (Y9) was the most effective strain for BA. The optimal ratio of added native bacteria to Y9 was 10:3. The BA column adapted to a high sulfolane concentration (150 mg L-1) more rapidly and had higher sulfolane removal efficiency (90%) than did the BS column. The change in the biotoxicity of sulfolane-contaminated groundwater upon bioremediation, according to a Microtox test, revealed decreases in the inhibition of the passing of light by the BS column and BS + BA column of 38% and 63%, respectively. These results reveal that combining BS with BA can reduce the biotoxicity of sulfolane. The column tests confirmed the most effective added bacterium in BA, the operating conditions for high-efficiency bioremediation, and possible problems in its future application. The results provide an important reference for the design of methods for the remediation of contaminated sites.

Bioremediation capability evaluation of benzene and sulfolane contaminated groundwater: Determination of bioremediation parameters.

Benzene and sulfolane are commonly used but hazardous chemicals in the petrochemical industry and their leakage and inappropriate disposal certainly causes serious soil and groundwater contamination. In this research, the bioremediation potential of groundwater contaminated with benzene and sulfolane was evaluated, and the operating parameters for bioremediation were established through laboratory batch experiments. Among the various bacterial consortia, the bacterial population of monitoring well c (MWc) contained the highest sulfolane and benzene removal efficiencies. When the dissolved oxygen (DO) level was >1 mg L-1, the bacterial population of MWc showed excellent removal efficiencies toward high and low concentrations of benzene and sulfolane. The C:N:P ratio of 100:10:1 in media facilitated sulfolane and benzene biodegradation, and the degradation time was greatly reduced. Adding additional phosphate into real groundwater could slightly increase benzene removal efficiency. Trace elements only slightly enhanced benzene degradation. On the contrary, additional phosphate and trace elements supplementary did not enhance sulfolane degradation. However, sulfolane removal efficiency could be significantly improved through bioaugmentation of specific sulfolane degrading bacterium and 100% sulfolane removal efficiency was achieved.

Pentachlorophenol contaminated groundwater bioremediation using immobilized Sphingomonas cells inoculation in the bioreactor system.

Pentachlorophenol (PCP) has been used as a wood preservative for more than 100 years. The extensive use of PCP has widely contaminated soil and groundwater. PCP is toxic to living organisms. The main objective of this research was to inoculate the pure PCP-degrading bacterium strain Sphingomonas chlorophenolica PCP-1, isolated from PCP-contaminated soils, into PCP-contaminated groundwater for remediation purposes. The factors that influenced the bioremediation were explored with batch experiments using the inoculated immobilized and suspended cells as inoculation. A biological treatment system inoculated with immobilized cells was set up to estimate the microbial capability to degrade PCP. The results indicated that the suspended and immobilized cells could be inoculated into PCP-contaminated groundwater without adding other supplementary nitrogen and phosphate sources in batch conditions. Moreover, PCP decomposition was accompanied with released Cl- and decreasing pH value. The optimum HRT in the bioreactor system was 12.6h. PCP removal in the bioreactor remained stable and PCP removal efficiency was higher than 92% at this phase. Furthermore, PCP concentration in the biotreatment system effluent remained undetectable. It is possible to bioremediate PCP-contaminated groundwater using immobilized S. chlorophenolica PCP-1 cells in a bioreactor system. The proposed biological treatment system could be maintained for at least for 2 months.

Isolation of 5-hydroxymethylfurfural biotransforming bacteria to produce 2,5-furan dicarboxylic acid in algal acid hydrolysate.

In dealing with lignocellulosic and algal biomass, thermal acid hydrolysis is an economical and efficient method. In this process, 5-hydroxy-methylfurfural (5-HMF) is formed unavoidably, which inhibits downstream reducing sugar fermentation. Fortunately, 5-HMF can be biotransformed into 2,5-furan-dicarboxylic acid (FDCA), the top 14 biomass platform molecules. Base on the connection between 5-HMF removal and FDCA production, microbes capable of biotransforming 5-HMF into FDCA are beneficial to raise biofuel yield and potential molecule production. In this research, pure strain Methylobacterium radiotolerans G-2 capable of transforming 5-HMF into FDCA was enriched and isolated from local campus soil, and its abilities of 5-HMF biotransformation and FDCA production were characterized. Strain M. radiotolerans G-2 could completely transform 1000 mg/L 5-HMF into FDCA with maximum concentration of 513.9 mg/L at an initial pH of 7 at 26°C. Algal acid hydrolysate after two-fold dilution was suitable for strain M. radiotolerans G-2 to perform 5-HMF biotransformation, and 459.7 mg/L FDCA could be obtained. Interestingly, strain M. radiotolerans G-2 did not significantly consume reducing sugar and reducing sugar consuming efficiency was less than 16%.

Isolation and physiological characterization of the pentachlorophenol degrading bacterium Sphingomonas chlorophenolica.

Many chlorophenols tend to persist in the environment, and they may become public health hazards. Among chlorophenols, pentachlorophenol (PCP) is a priority pollutant that has been used widely as a general biocide in commercial wood treatment. Owing to the rapid industrial growth, serious soil and water pollutions by chlorophenols has been reported in Taiwan. In this study, 10 indigenous PCP-degrading bacterial strains were isolated from a PCP-degrading mixed culture, and the potential of both the pure and mixed cultures for PCP degradation compared. Moreover, the physiological characteristics and optimum growth conditions of the PCP-degrading bacteria were investigated. One of the isolated bacterial strains with good potential for PCP degradation was characterized and identified as Sphingomonas chlorophenolica by 16S rDNA gene analysis. The result of the optimum growth temperatures revealed that this organism was a mesophile. The optimum pH for PCP removal by S. chlorophenolica was between 6.9 and 7.6. Increase in concentration of PCP has a negative effect on the biodegradation potential of S. chlorophenolica and PCP concentration above 600 mg l(-1) was inhibitory to its growth. The results of this study indicate that this S. chlorophenolica strain has a better potential for PCP degradation compared to the enriched mixed culture. The physiological characterization of the isolates also indicates the possible application of this strain for bioremediation of sites contaminated with PCP.

Biotransformation of 5-hydroxy-methylfurfural into 2,5-furan-dicarboxylic acid by bacterial isolate using thermal acid algal hydrolysate.

Thermal acid hydrolysis is often used to deal with lignocellulosic biomasses, but 5-hydroxy-methylfurfural (5-HMF) formed during hydrolysis deeply influences downstream fermentation. 2,5-Furan-dicarboxylic acid (FDCA), which is in the list of future important biomass platform molecules can be obtained using 5-HMF biotransformation. Based on the connection between 5-HMF removal in acid hydrolysate and FDCA production, the optimum thermal acid hydrolysis condition for macroalgae Chaetomorpha linum was established. Potential microbes capable of transforming 5-HMF into FDCA were isolated and characterized under various parameters and inoculated into algal hydrolysate to perform 5-HMF biotransformation. The optimum hydrolysis condition was to apply 0.5M HCl to treat 3% algal biomass under 121°C for 15min. Isolated Burkholderia cepacia H-2 could transform 2000mg/L 5-HMF at the initial pH of 7 at 28°C and 1276mg/L FDCA was received. Strain B. cepacia H-2 was suitable for treating the algal hydrolysate without dilution, receiving 989.5mg/L FDCA.

Enhancement of photohydrogen production using phbC deficient mutant Rhodopseudomonas palustris strain M23.

This study used a DNA recombination method to knock out the poly-ß-hydroxybutyrate (PHB) synthesis gene phbC in the photosynthetic bacterium Rhodopseudomonas palustris WP3-5. The experimental results indicated that the mutant strain Rps. palustris M23 could be successfully screened. Fluorescent observation with Nile blue staining showed no significant PHB granule accumulation in the mutant cells. Batch mode experiments using acetic acid as a carbon source revealed a 29.1% and 25.9% hydrogen gas content from M23 and WP3-5, respectively. However, this trend did not appear when using propionic acid as carbon source. Under continuous operation, the hydrogen gas content from M23 could be maintained above 72%. The average hydrogen production rates of the WP3-5 and M23 strains were 264 mL-H(2)/L/day and 457 mL-H(2)/L/day, respectively. The total biogas volume collected from M23 was 1.7 times higher than that from the wild type.

Hydrogen production by Rhodopseudomonas palustris WP 3-5 in a serial photobioreactor fed with hydrogen fermentation effluent.

In this study, a lab-scale serial photobioreactor composed of three column reactors was constructed and continuously operated to investigate several parameters influencing photohydrogen production when using the synthetic wastewater and the anaerobic hydrogen fermentation effluents as the influents. The results indicated that better hydrogen production rate was obtained when the serial photobioreactor was operated under cellular recycling at a short HRT of 8h. The serial photobioreactor maintained high hydrogen content ca. 80% in the produced gas and 0.4× dilution ratio was the suitable ratio for hydrogen production. When the photobioreactor fed with the real wastewater (Effluent 1) containing 100 mg/L NH4Cl, Column 1 reactor successfully reduced ammonia concentration to about 60 mg/L for cell synthesis, resulting in a steady hydrogen production in the following two column reactors. The average hydrogen production rate was 205 mL-H2/L/d.

Enrichment, isolation, and characterization of 4-chlorophenol-degrading bacterium Rhizobium sp. 4-CP-20.

The objectives of this research were to monitor the variations of species in mixed cultures during the enrichment period, isolate species and identify and characterize the pure 4-chlorophenol (4-CP) degrading strains from enriched mixed cultures. Strain Rhizobium sp. 4-CP-20 was isolated from the acclimated mixed culture. The DGGE result indicated that strain Rhizobium sp. 4-CP-20 was undetectable at the beginning but detectable after 2 weeks of enrichment. The optimum growth temperatures for Rhizobium sp. 4-CP-20 were both 36 degrees C using 350 mg l(-1) glucose or sodium acetate as the substrate. The optimum pH range for degrading 100 mg l(-1) 4-CP was between 6.89 and 8.20. Strain Rhizobium sp. 4-CP-20 could degrade 4-CP completely within 3.95 days, as the initial 4-CP concentration was 100 mg l(-1). If the initial 4-CP concentration was higher than 240 mg l(-1), the growth of bacterial cells and the activity of degrading 4-CP were both inhibited.

Degradation of chlorophenols using pentachlorophenol-degrading bacteria Sphingomonas chlorophenolica in a batch reactor.

Chlorophenols are common environmental contaminants that have been used as the major component in wide-spectrum biocides in industry and agriculture. Many chlorophenols tend to persist in the environment and may become public health hazards. This research studied the ability of the pentachlorophenol (PCP)-degrading bacterium Sphingomonas chlorophenolica to degrade and dechlorinate other chlorophenols. In addition, the characteristics of S. chlorophenolica were also investigated. When S. chlorophenolica cells were preincubated with PCP, the lag phase PCP degradation periods became shorter and the PCP concentrations that could be removed became higher. S. chlorophenolica was able to completely degrade 2,3,6-trichlorophenol (2,3,6-TCP), 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP), and PCP within 38.1, 15.1, 11.8, and 11.8 h, and to release concentrations of 50.1, 60.9, 63.7, and 58.5 mg/L chloride at the same period of time. In the presence of supplementary carbon sources, the PCP removal efficiency increased with the presence of glucose or pyruvate. However, the removal efficiency of 75 mg/L 2,4-dichlorophenol did not increase with supplemental carbon sources.