Enzymatic Degradation and Aminolysis of Microbial Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) Single Crystals

Solution-grown single crystals of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] were hydrolyzed by polyhydroxybutyrate (PHB) depolymerase from Ralstonia pickettii T1. Enzymatic degradation proceeded from the edges of lamellar crystals, yielding serrated contour and small crystal fragments. Gel permeation chromatography analysis revealed that the molecular weights of the crystals decreased during enzymatic degradation, suggesting that the enzymatic hydrolysis of chain-folding regions at the crystal surfaces occurred in addition to the enzymatic degradation at crystal laterals or edges. After P(3HB-co-4HB) single crystals were aminolysed in 20% aqueous methylamine solution to remove the folded-chain regions and enzymatic degradation by lipase from Rhizopus oryzae to remove 4HB components at crystal surfaces of single crystal aminolyzed, it was found that a small amount (up to ca. 2 mol%) of 4HB component can be incorporated into the P(3HB) mother crystal lattice irrespective of the 4HB content.     

Prospects for a self-sustainable sewage treatment system: a case study on full-scale UASB system in India's Yamuna River Basin

The government of India decided to launch a project to implement 16 full-scale Upflow Anaerobic Sludge Blanket (UASB) reactors (with a total capacity of 598,000 m(3)/d) in the Yamuna River basin under its Yamuna Action Plan (YAP). A polishing pond called the Final Polishing Unit (FPU) was utilized for post-treatment. This paper evaluates the sewage treatment efficiency of the combined system of full-scale UASB reactors and polishing ponds under Indian climatic conditions. Results have shown that the effluent from the sewage treatment plants (STPs) investigated failed to comply with applicable discharge standards in terms of BOD, SS, and fecal coliform removal. Therefore, it is proposed that such proper operation and maintenance as removing excess sludge and scum be conducted in order to increase treatment efficiency. Moreover, trained and experienced workers are also required to operate and maintain the systems, along with a scientific approach.     

CWO技术处理高浓度焦化废水的工业应用研究

采用 2 0 0 L/ d CWO小型工业试验装置对高浓度焦化废水进行处理试验研究 ,结果表明 CWO技术装置对处理高浓度焦化废水 (CODCr,10 0 0 0～ 130 0 0 mg/ L、NH3- N12 0 0～ 2 10 0 mg/ L)具有良好的技术可行性 ,废水经处理后 (催化反应时间 30～ 4 5 min) ,废水中 CODCr、NH3- N的去除率即可达到 99%以上 ,处理水中的 CODCr、NH3- N浓度均可达到国家排放标准 (CODCr<10 0 mg/ L、NH3- N<15 mg/ L ) ,且废水的脱色、除臭效果明显。对于不同浓度焦化废水的处理 ,CWO技术及装置表现出了很好的适应性。国产化 2 0 m3/ d CWO工业装置对焦化废水的连续处理运行表明 ,CWO技术在国内已达到工业化应用水平 ,并具有较好的经济性。     

Optimization of the ionization conditions for the trace analysis of PCDD/PCDF with ion trap MS/MS

Commercial ion trap mass spectrometer provides easy-to-operate MS/MS analysis for the determination of PCDD/PCDF. The limit of quantification is appropriately low (0.2 pg for 23478-P5CDF) because all the stages are performed in the trap and sample losses associated with the ion transportation are minimized. However, if excessive ions are injected into the trap, its electrical fields are distorted and an overall reduction in performance arises. Ionization condition is an important parameter as it affects the amount of the total ions produced. If the amount of interfering compounds are negligible, such as standard solution or cleaned-up sample, lower ionization condition (e.g. electron energy: 30 eV, emission current (EC): 150 μA) is preferable. On the contrary, in case excessive interfering ions are coexisting with PCDD/PCDF, such as crude extract or semi-cleaned-up sample, the ionization condition should be high (e.g. electron energy: 90 eV, EC: 350 μA) for the reproductive quantification.     

Seasonal change of persistent organic pollutant concentrations in air at Niigata area,Japan

The concentrations of persistent organic pollutants (POPs), such as HCB, alpha-, beta-, gamma- and delta-HCH, trans- and cis-chlordane (t-CHL, c-CHL), DDE, DDD and DDT, in ambient air have been measured at five sampling points in Niigata area, Japan (Niigata, Maki, Tsubame, Jouzo and Yahiko) during the period from September 1999 to November 2001. HCB, alpha-HCH, t-CHL and c-CHL showed higher concentrations than the other chemicals in all locations. All the POPs except t-CHL and c-CHL collected at urban sites of the Niigata Plain was almost the same in their concentration levels. Higher concentrations of t-CHL and c-CHL in residential areas should be attributed to the past usage of the chemical as a termiticide. At Yahiko (remote site), most of the POPs showed lower concentrations than those measured at the other sampling sites, although alpha-HCH and gamma-HCH were comparable with the concentrations found at the other sampling sites. All POPs except alpha-HCH and gamma-HCH tend to decrease 41-80% in their concentrations from 2000 to 2001. The lower POPs concentrations in winter and the higher POPs concentrations in summer at every sampling point can be partly explained by temperature differences. Applying the equation of the logarithm of the POP partial pressure in air versus reciprocal temperature (lnPa=m/T+b) to our data, linear relations were observed. HCB gave a poor linearity and the smallest slope, while beta-HCH, t-CHL and c-CHL gave good linearities and large slopes in the equation. The results suggest that HCB level is influenced by not only the emission from terrestrial sources but the global-scale background pollution. A peculiar observation is that beta-HCH concentration measured in our study showed large temperature dependence, indicating there could be a source of contamination in the surrounding areas.     

Polyfluorinated telomers in indoor air of Japanese houses

The fluorotelomer alcohols (FTOHs) have been detected in various environmental compartments, including indoor and outdoor air, in North America and Europe. In our previous studies, FTOHs were detected at a relative higher concentration in outdoor air in the Keihan (Kyoto–Osaka, one of the major industrial zones) area, Japan compared to reported data. The exposure level of FTOHs in indoor air in the Keihan area remains unclear. In the present study, indoor air FTOH concentrations were investigated using a passive air sampler containing activated carbon felts. The indoor air sampling was conducted in 49 households of the Keihan area, during winter and summer 2008. Most samples contained 6:2 FTOH, 8:2 FTOH, 10:2 FTOH and 8:2 FTOAc. The median concentration of 8:2 FTOH (5.84 ng m^?3) was highest among fluorotelomers, followed by those of 10:2 FTOH (1.12 ng m^?3), 6:2 FTOH (0.29 ng m^?3), and others. Significant correlations among fluorotelomers were observed in collected samples. The association between housing conditions and 8:2 FTOH concentrations showed that samples collected from bed rooms have higher 8:2 FTOH concentrations than those collected from other locations. In addition, samples collected in winter showed lower levels of 8:2 FTOH than those collected in summer. These findings suggest that 8:2 FTOH is the predominant component among fluorotelomers in indoor air, and that there are emission sources of fluorotelomers in indoor environments of the Keihan area. Further investigations into the origins of fluorotelomers are needed to evaluate indoor contamination with fluorotelomers.     

Development of enzyme immunoassay for detection of DDT

Dichlorodiphenyltrichloroethane (DDT) is one of the persistent organic pollutants (POPs) widely found in the environment and in the general population. In this study, a direct competitive enzyme immunoassay (EIA) has been developed for the quantitative analysis of DDT. To generate a specific polyclonal antibody for EIA, p, p'-DDT was conjugated to porcine thyroglobulin for rabbit immunization. At optimized EIA conditions, the standard curves ranged from 0.137 to 100 ng/mL with the quantification limit of 0.41 ng/mL. The coefficients of variation (CV%) were 5.42-10.53% for intra-assay and 6.04-7.26% for inter-assay. Cross-reactivities with DDT metabolites (DDTs, including o, p'-DDT, p, p'-DDD, o, p'-DDD, p, p'-DDE, o, p'-DDE, p, p'-dichlorobenzophenone (DCBP), o, p'-DCBP) were investigated. The polyclonal antibody showed relatively low and/or no cross-reactivity with these compounds, and the assay was seen to be highly selective for p, p'-DDT. Moreover, the DDTs could be ranked by their reactivity: DDT > DDD > DDE > DCBP. In addition, the characterization of the polyclonal antibody indicated that the antiserum possesses a high specificity for p, p'-isomers. The results indicated that the developed EIA using this antibody could be a convenient and supplemental analytical tool for monitoring DDT.     

Mercury pollution in the Tapajos River basin, Amazon: mercury level of head hair and health effects.

There is increasing concern about the potential neurotoxic effects of exposure to methylmercury for the 6 million people living in the Amazon, even in regions situated far away from the gold mines (garimpos), considered to be the major source of mercury pollution. In November 1998, a spot investigation on mercury contamination was conducted in three fishing villages (Barreiras, Rainha, and Sao Luiz do Tapajos) on the Tapajos River, an effluent of the Amazon, situated several hundred kilometers downstream from the gold-mining areas. A total of 132 fishermen and their families volunteered for the current study. As was anticipated, the total mercury levels in the head hair collected from the fishing villages were relatively high (14.1-20.8 ppm on the average) and the number of subjects with a high total mercury level over 10 ppm (the least upper bound of a normal value) was 103 (78.0%) in total, along with various symptoms, thereby suggesting wide mercury contamination in the Tapajos River basin. Moreover, in view of the absence of other diseases (e.g., alcoholism or malaria), a high intake of fish containing a methylmercury level, and high hair mercury levels in addition to the various symptoms such as sensory disturbance (especially glove-and-stocking type, which is characteristic of Minamata disease), tremor, failure in two-point discrimination, and slight balancing failure, several subjects examined were diagnosed with mild Minamata disease. The findings obtained suggest, thus, that the mercury pollution in the Amazon should be crucially observed for head hair mercury level and health in a much broader region.