In this study, EPS produced by five Bacillus spp. strains was determined. The only one strain (B. sphaericus 7055) was selected due to its high EPS production and it was investigated by growing this strain in LB broth medium containing
various carbon sources. The highest EPS production of this strain was found in medium containing fructose. However, the effect
of different concentrations of fructose and molasses on EPS production by the strain was studied. The maximum EPS yield of
the strain 7055 was recorded with 2.5% (w/v) fructose, also the highest EPS production was found in 2.5% (w/v) molasses. The
strain 7055 was found to contain (98.6%) galactose and (1.4%) glucuronic acid in control medium whereas the composition of
the strain 7055 (2.5% (w/v) fructose) was found to be (99.9%) neutral sugar and (0.1%) Glucuronic acid while the strain 7055
(2.5% (w/v) molasses) was found to contain (65.9%), neutral sugars and (34.1%) glucuronic acid. 相似文献
Remote sensing technology offers an opportunity to significantly increase the amount of site-specific information about field characteristics such as pest populations. Coupled with variable rate application technologies, this added information has the potential to provide environmental benefits through reduced pesticide applications. However, producers face a complicated adoption decision because output prices and crop yields are uncertain. A model is developed to examine the potential value of remote sensing information to pesticide applications in an option-value framework under uncertainty. Simulations suggest that remote sensing information could decrease pesticide use, but uncertainty and irreversibility are likely to limit technological adoption by farmers. Potential cost-share subsidies are discussed. 相似文献
To reduce nonpoint source pollution from nutrient, chemical, and sediment runoff, a number of environmental policy standards have been proposed. Such standards could be used to reduce nonpoint source pollution from nutrient, chemical, and sediment runoff to impaired water bodies. State governments can use voluntary approaches to meet nonpoint source pollution reduction goals. However, the practices that lower net returns will not be voluntarily adopted by farmers. Crop rotations and tillage practices may help producers to comply with the environmental standards while minimizing losses in farm profits. This study compares runoff from crop rotation practices and conventional continuous row cropping systems in Mississippi. The results are compared for different tillage systems in order to examine robustness of results. Nutrient runoff and sediment runoff are simulated using the Erosion Productivity Impact Calculator (EPIC). Sensitivity analysis of the sediment and nitrate reductions at 15 percent, 25 percent, and 35 percent are conducted. Under these scenarios, net returns are optimized under environmental constraints, and the marginal cost of sediment reduction ranges from US$1.61 to US$9.63 per ton depending on soil conditions, while the corresponding nitrate and phosphorus reductions costs range from US$1.21 to US$7.08 per kg and from US$0.09 to US$31.91, respectively. The empirical results from this study indicate that a nitrate reduction policy is relatively less costly than a sediment reduction policy. The results also demonstrate the importance of geophysical conditions and policy costs, which vary across regions. 相似文献
This paper reviews the factors influencing the development and sustained operation of regional industrial symbiosis (IS) networks and discusses the roles a coordination body can play to alter these factors so as to catalyse the development and functioning of such networks. These are analysed within the context of experiences gained in the early stages of three regional IS programmes under development in the UK, and of the recently launched national IS programme (NISP) that they are part of. It is stated that the policy framework in the UK has elements supportive of such networks to evolve, and the regional public bodies are favouring their development. Based on differences among studied cases, it is argued that the nature of companies’ operations and industrial history in the regions, the extent of peer pressure, the positioning of the coordinating body in the region, and its approach to awareness raising and recruitment have major influence on the progress of the programmes. Finally, the paper emphasises the importance of aligning the characteristics of emerging operations with the longer-term sustainability requirements. If accepted, this challenge assigns additional responsibilities to the coordinating parties. 相似文献
The De?irmendere and Galyan (De?irmendere tributary) Rivers that discharge their water into the Black Sea are important watersheds in the northeastern part of Turkey. Water quality parameters were sampled from 1997 through 2001 for each year at five sites (three for Galyan, two for Degirmendere) along 29 and 42 km gradients, respectively covering all seasons. Surface water was collected from the sites and analyzed for temperature, total alkaline (MAAL), total dissolved solids (TDS), dissolved oxygen (DO), pH, conductivity (EC), nitrate (NO3), nitrite (NO2), total hardness (TH), phenolphthalein alkalinities (PAL) and organic matter (PV). Seasonal changes of water quality were analyzed statistically for both Rivers and evaluated according to the TS 266, EU and WHO standards. The analysis of variance results showed that Ca, Mg, MAL, NO3, pH, TDS and TH parameters of the De?irmendere River and Ca, DO, EC, MAL, NO3, pH and TH parameters of the Galyan River showed seasonal differences (p<0.05). The maximum values of the water pollution parameters for the two Rivers were below the threshold values throughout the study period. When both Rivers were compared, the mean values of the pollution parameters of the Degirmendere River were higher than those of the Galyan River and very close the limits. The results indicate that both Rivers can be used for the production of potable water during all seasons but only with an advanced treatment in the De?irmendere and a moderate treatment in the Galyan River, and for indirect and non-contact recreational activities. 相似文献
In this study, modified polyacrylamide (PAAm) cryogels with high dye holding capacity were synthesized with an easily and cheaply process and adsorption of Remazol Black B (RBB) with the synthesized materials was investigated. Firstly, PAAm cryogels were synthesized with free radical cryo-copolymerization method and they were modified with Hofmann reaction to form amine groups in the structure of the cyrogels. Then, to increase the removal efficiency of cryogels, polyethylenimine (PEI) molecules were crosslinked onto the cryogels via NH2 groups present in the PAAm gels modified by the Hofmann reaction. The original and modified cryogels were characterized with fourier transformed infrared spectroscopy, 13C nuclear magnetic resonance spectroscopy, scanning electron microscopy and thermogravimetric analysis. The point of zero charge (pHpzc) of the modified cryogels was found to be 7.13 and RBB removing capabilities of PEI-modified PAAm cryogels were investigated at pH between 2 and 7. In addition, the adsorption treatments were performed at different process time, incubation temperature, initial dye concentration and adsorbent amount to find maximum removal capacity of the adsorbent. The modified cryogels adsorbed maximum amount of RBB at pH 2 and the sorption process reached equilibrium in 6 h. It was observed that the adsorption efficiency did not change much with the increase in temperature. The maximum RBB removal capacity of the modified cyrogels was determined to be 201 mg/g when the initial RBB concentration was 200 mg/L, treatment time was 6 h at pH 2. Moreover, the adsorption of RBB dye with the modified cryogels takes place with a second order kinetic and RBB dye adsorption data showed compliance with the Langmuir isotherm. The findings of the study expose that the obtained PEI-modified PAAm cryogels are a hopeful material for RBB removal in aqueous environment.
Environmental Science and Pollution Research - In this study, the hazards occurring in a medium-sized gas filling facility were defined, and the risk scores of these hazards were determined by the... 相似文献