Equilibrium, kinetics and thermodynamics of biosorption of U(VI) by Jonesia quinghaiensis strain ZFSY-01 isolated from the wastewater of a uranium mine

The adsorption ability of a native Jonesia quinghaiensis strain ZFSY-01, a microorganism isolated from uranium tailing wastewater, to U(VI) in wastewater under different conditions was studied in this work. The results showed that 391.5 mg U/g and 78.3% of adsorption capacity and efficiency were achieved under an optimum adsorption condition, respectively. Especially, the adsorption capacity of this strain reached the maximum (Q=788.9 mg U/g) under 100 mg/L of strain dosage. Simultaneously, the linear regression coefficients for the used isothermal sorption model indicate that the biosorption process is compatible with the Freundlich isotherm, the Temkin isotherm and the Halsey isotherm model. Based on the fitted kinetic parameters, the data from the experiments fit well with models of pseudo-second-order kinetics and intraparticle diffusion, suggesting that the strain ZFSY-01 immobilized U(VI) by physical and chemical adsorption. In addition, thermodynamic parameters demonstrated that the sequestration of U(VI) by the strain is spontaneous and endothermic. Based on the above analysis, strain ZFSY-01 can effectively remove U(VI) ions from high- or low-concentration uranium-containing wastewater and is expected to become a promising biological adsorbent. HIGHLIGHTS Specific microbes in special habitats have potential efficacy.; Adsorption capacity of strain ZFSY-01 reached 788.9 mg U/g under 100 mg/L of dosage.; Strain ZFSY-01 immobilized U(VI) by physical and chemical adsorption.; It is expected to be a green and efficient biosorbent material.

Engineering of gentiopicroside-producing yeast strain using low-energy ion implantation mediated synthetic biology

To obtain an alternative source for the production of gentiopicroside, here genomic DNA segments of the medicinal plant Gentiana macrophylla were randomly transferred into Hansenula polymorpha by 25 KeV nitrogen ions (N+) at a dose of 2.5 × 1016 ions/cm2 under vacuum pressure of 1 × 10−3 Pa. To screen for potential gentiopicroside-producing recombinant yeast strains, geraniol 10-hydroxylase (G10H) and secologanin synthase (SLS) involved in the gentiopicroside biosynthesis pathway were used as molecular markers. Based on the conserved protein sequences of G10H and SLS, degenerate primers were designed and used for colony polymerase chain reaction (PCR). PCR-positive results for both the G10H and SLS genes were obtained in 79 out of 653 transformants by low-energy ion beam-mediated transformation. These 79 potential gentiopicroside-producing strains were further analysed by Fehling's test, thin-layer chromatography, high performance liquid chromatography and high performance liquid chromatography-mass spectrometry. The results showed that the retention time and ion peaks of the sample from one stable recombinant strain designated as DL67 were consistent with those of the gentiopicroside standard. The corresponding gentiopicroside yield was 8.41 mg/g dry cell weight after strain DL67 was cultured for 96 h. This could offer a new starting point for the construction of recombinant yeasts for production of medicinal plant compounds

Study on the practice of downhole dewaxing by in situ generated heat

Abstract In situ heat systems are a technology that effectively solves paraffin deposition and improves oil recovery. Generally, the oxidation–reduction reaction of sodium nitrite and ammonium chloride generates a large amount of heat to promote the melting of paraffin. An in situ heat system combined with an acid-resistant fracturing fluid system can form an in situ heat fracturing fluid system, which solves the problem of the poor reformation effect caused by cold damage during the fracturing process of low-pressure and high-pour-point oil reservoirs. In this paper, with the goals of system heating up to 50 °C, a low H+ concentration, a high exotherm, and reduction of the toxic and harmful by-product NOX, the preferred in situ heat system was found to comprise 1.6 mol/L ammonium chloride, 1.0 mol/L sodium nitrite, and 0.8% hydrochloric acid. The effect of five factors on the heat production of the reaction was studied experimentally, and a reaction kinetic equation for the in situ heat system was proposed based on the results. The results showed that increasing the concentration of the reactants and lowering the ambient temperature produced more heat. The in situ heat system was used to conduct a crude oil cold damage elimination experiment, and the results of the removal experiments verified that the system could effectively but not completely reduce the cold damage. Overall, the in situ heat fracturing fluid system formed by the preferred in situ heat system combined with an acid-resistant fracturing fluid system could avoid cold damage in the formation during construction and increase the output

Multi-angle evaluation of the anaerobic digestion of Molasses vinasse using two different feeding patterns

Molasses vinasse (MV) is a waste burden in alcohol production due to its high organic matter content. However, it represents a potential source of energy recovery if adequately treated. In this study, two feeding patterns (pulse feeding: 8 ​L/4 ​h and semi-continuous feeding: 8 ​L/23 ​h) were evaluated for their effects on MV anaerobic digestion from multiple perspectives in a laboratory-scale reactor. The results demonstrated that semi-continuous feeding not only achieved a higher soluble chemical oxygen demand (sCOD) removal rate of 78.48% but also increased the production of biogas and methane by 20.04% and 51.48%, respectively. In addition, the chemical composition analysis suggested that the semi-continuous feeding pattern degraded the majority of lignin/CRAM and aromatic substances more effectively than the pulse feeding pattern. Moreover, the microbial analysis revealed that semi-continuous feeding increased the number of dominant bacteria, including Chloroflexi, Synergistetes, and Cloacimonetea, and methanogenic archaea, including Methanosaeta and Methanosarcina. The findings of this study, therefore, confirm that the semi-continuous feeding model is more effective and has good application potential, laying the groundwork for the MV anaerobic industrial processes

Short-Term Effects of Ambient Air Pollution on Hospitalization for Respiratory Disease in Taiyuan, China: A Time-Series Analysis

In this study, we estimated the short-term effects of ambient air pollution on respiratory disease hospitalization in Taiyuan, China. Daily data of respiratory disease hospitalization, daily concentration of ambient air pollutants and meteorological factors from 1 October 2014 to 30 September 2017 in Taiyuan were included in our study. We conducted a time-series study design and applied a generalized additive model to evaluate the association between every 10-μg/m3 increment of air pollutants and percent increase of respiratory disease hospitalization. A total of 127,565 respiratory disease hospitalization cases were included in this study during the present period. In single-pollutant models, the effect values in multi-day lags were greater than those in single-day lags. PM2.5 at lag02 days, SO2 at lag03 days, PM10 and NO2 at lag05 days were observed to be strongly and significantly associated with respiratory disease hospitalization. No significant association was found between O3 and respiratory disease hospitalization. SO2 and NO2 were still significantly associated with hospitalization after adjusting for PM2.5 or PM10 into two-pollutant models. Females and younger population for respiratory disease were more vulnerable to air pollution than males and older groups. Therefore, some effective measures should be taken to strengthen the management of the ambient air pollutants, especially SO2 and NO2, and to enhance the protection of the high-risk population from air pollutants, thereby reducing the burden of respiratory disease caused by ambient air pollution