Advanced Materials Research Vols. 1010-1012

Abstract: The quantitative structure property relationship (QSPR) study was performed in this work to develop models to predict the normalized reaction rate constants for the reductive debromination of polybrominated diphenyl ethers (PBDEs) by zero-valent iron (ZVI). In order to consider the solvent effect, conductor-like polarizable continuum model (CPCM) was applied to optimize the geometries and obtain the molecular descriptors using the pseudopotential basis set. The prediction results with the inclusion of solvent effect are slightly better than that of the corresponding gas-phase calculations. The artificial neural network (ANN) model could be more satisfactory to predict the rate constants than the partial least squares regression (PLSR) and principal component analysis-multiple linear regression analysis (PCA-MLR) models.

Abstract: Streptomycin (STR) was the bactericidal antibiotic used extensively in human and veterinary medicine with a high aqueous solubility. In this study, the adsorption of STR on soil was studied as a function of pH, cationic types and ionic strength by using adsorption modeling and bath experiments. Adsorption modeling of the adsorption of STR was better fitted with the Freundlich as compared to the Langmuir. The absorbed STR on soil kept relatively constant at pH 3.5-8 and decreased at pH>8. And the order of cationic influence was CaCl₂> NaCl≈KCl> the blank sample for STR sorption capacity, suggesting that the sorption of STR increased as the presence of low concentrations of the cationic. The amount of STR adsorbed was inversely proportional to the logarithmic concentration of the background cations.

Abstract: This paper discusses the utilization situation and existing problems of sugarcane bagasse, and briefly the research progress of preparation of activated carbon from sugarcane bagasse (ACSB). It reviews the application of activated carbon prepared from sugarcane bagasse, such as, industrial wastewater decolorizing, removal of organic pollutants and heavy metals in wastewater in the domestic and overseas in recent years. Points out the shortage of preparation methods, the existing problems and puts forwards some questions need to be solved in future research. Moreover, the prospect of application and the trends in future research of activated carbon from sugarcane bagasse are proposed.

Abstract: The number of substrate microorganisms and enzyme activities of a lab-scale subsurface infiltration system (SIS) were monitored by plate counts, MPN and colorimetric analysis. The removal rates of BOD, COD, TP, TN and ammonia-N were measured. The results showed there were significantly positive correlation (P<0.05) between numbers of bacteria, fungi in the substrate and removal rates of COD and BOD. The correlation between number of nitrifying bacteria and removal rates of ammonia-N and correlation between number of denitrifying bacteria and removal rates of TN were significant. Meanwhile, a significant correlation between phosphatase activities and removal rates of TP (r=0.9885, P<0.05) can be also found. There was significantly positive correlation between urease activities and removal rates of TN (r=0.9698, P<0.05). These conclusions give reference to future research on utilizing substrate microorganisms and enzyme activities as an evaluating wastewater purification effects in SIS.

Abstract: Microbial method with high efficiency and low pollution on oilfield sewage treatment, has more advantages than others, however, the salinity of sewage is rather high due to the high content of calcium and magnesium ions, sulfate and carbonate ions. High salinity results in strong fouling resistance, the crystals of calcium scale will easily gather and deposit on microbial surface and hinder matter and energy exchange processes between in and outside of microbial cell. The worst case is that scale will impact the normal oilfield production. This paper explores the principles and characteristics of dirt deposited on the surface of microorganisms, the mechanisms of fouling , as well as introduces the research status of CaCO₃ scale and BaSO₄ scale at home and abroad.

Abstract: Microbial degradation of hydrocarbon in contaminated salterns has attracted increasing attention. However, the diversity of hydrocarbons-degrading bacteria in such environments was still poorly understood. A total of 14 bacteria were isolated from a petroleum-contaminated saltern, which could grow in 3% NaCl. Especially, 2 isolates can survive in 20% NaCl. In addition, all isolates degraded petroleum. However, only 12, 8 and 3 isolates degraded phenanthrene, pyrene and n-Hexadecane, respectively. Phylogenetic analysis showed the isolates belonged to the genera Achromobacter, Rhodococcus, Mycobacteriumi, Dietzia, Sphingobium, Pseudomonas, Ochrobactrum, Bacillu, Rhizobium, Halomonas, Idiomarina, Chromohalobacter and Marinobacter. Hydrocarbon-degrading activity of Achromobacter pulmonis, Bacillus persicus, Rhizobium helanshanense, Halomonas xianhensis and Idiomarina loihiensis in petroleum-contaminated saltern was reported for the first time.

Abstract: Global climate change affects not only rice yield but also grain quality. A better understanding of the effect of environment factors on rice yield and quality provides information for breeding new varieties adapted to a changing world. This study uses indica-japonica recombinant inbred lines (RILs) constructed in different ecological regions of China as test materials. The objectives were to determine the effect of environment on rice yield and quality. The results revealed that: the yield of RILs in Liaoning was greater than that in the other regions, milling and appearance qualities in Sichuan and Guangdong were worse than that in Liaoning and Shanghai. High temperature and high relative humidity combined with low sunshine duration were the main reason for lower milling quality and greater chalkiness traits. The air temperature during heading stage and maturity stage seemed more important for rice milling and appearance qualities throughout the growing season.

Abstract: The photosynthetic characteristic of plants may reflect the situation of growth and drought resistance. This study showed that drought affected significantly the P_n and T_r of Hemarthria compressa, the daily variation of Pn and T_r showed the “single peak” curve under different water condition, however, the change trend was totally opposite; the G_s and the C_i decreased with the increase of water stresses; the peak value of WUE of different water condition appeared before 10:00AM; the WUE decreased with the increase of T_r after 10:00AM. The WUE of different water stresses were higher than control before 12:00AM, however, less than control during 12:00 to 18:00. Hemarthria compressa generally tends to reduce the stomatal opening and transpiration in order to achieve high WUE under the water deficit, which belongs to strong drought resistance forage species.

Abstract: The production of laccase by solid-state fermentation (SSF) using Armillariella tabescens was studied. Wheat bran was selected to be the most suitable solid substrate. Several operational variables including nitrogen source, moisture content, copper and aromatic inducers were investigated. The results showed that the complex nitrogen sources, NH₄NO₃ coupled with peptone was shown to be the best nitrogen source. 75% of initial moisture content was proved to be appropriate. Copper significantly influenced the laccase production and the yield of laccase was improved by addition of 1.5 mM copper sulphate in the medium. Guaiacol efficiently induced the laccase production and the enzyme yield (24500U/g) was enhanced by 32% compared with he control without any aromatic inducers. Efficient production of laccase from A. tabescens can be achieved by solid-state fermentation.