Biodegradability of Epoxidized Soybean Oil Based Thermosets in Compost Soil Environment

In this study, bio-thermoset from epoxidized soybean oil (ESO) was prepared in the presence of methylhexahydrophthalic anhydride curing agent and 2-ethyl-4-methylimidazole catalyst. The crosslink densities of the synthesized ESO are ranged from 0.109 × 10^?3 to 0.308 × 10^?3 mol/cm³. The ESO bio-thermosets were exposed to the soil-burial test for 8 months. Weight change and morphology of the degraded ESO specimens were assessed. It was found that the weight loss of ESO was governed by the materials compositions, crosslink density and the soil-burial exposure time. The 3 mm thickness ESO bio-thermosets with crosslink density of 0.109 × 10^?3 mol/cm³ had fully biodegraded after soil-burial for 6 months. In addition, 16S rDNA sequencing was carried out to identify the soil microorganisms. It was suggested that Comamonas sp., Bacillus sp., Streptomyces sp. and Acinetobacter sp. are the possible soil microbes that degrade the ESO bio-thermosets in the compost soil environment.     

The contemporary cement cycle of the United States

A country-level stock and flow model for cement, an important construction material, was developed based on a material flow analysis framework. Using this model, the contemporary cement cycle of the United States was constructed by analyzing production, import, and export data for different stages of the cement cycle. The United States currently supplies approximately 80% of its cement consumption through domestic production and the rest is imported. The average annual net addition of in-use new cement stock over the period 2000–2004 was approximately 83 million metric tons and amounts to 2.3 tons per capita of concrete. Nonfuel carbon dioxide emissions (42 million metric tons per year) from the calcination phase of cement manufacture account for 62% of the total 68 million tons per year of cement production residues. The end-of-life cement discards are estimated to be 33 million metric tons per year, of which between 30% and 80% is recycled. A significant portion of the infrastructure in the United States is reaching the end of its useful life and will need to be replaced or rehabilitated; this could require far more cement than might be expected from economic forecasts of demand for cement.     

Carbon mitigation potential of Indian steel industry

Steel dominates the global metal production accounting for 5 % of increase in Earth’s atmospheric carbon dioxide (CO₂). Today, India is the 4th largest producer of crude steel in the world. The sector contributes around 3 % to the country’s gross domestic product (GDP) but adds 6.2 % to the national greenhouse gas (GHG) load. It accounts for 28.4% of the entire industry sector emissions, which are 23.9% of the country’s total emissions. Being a developing country, India is not obliged to cut its emissions under the Kyoto Protocol to the United Nations Framework Convention on Climate Change (FCCC), but gave voluntary commitment to reduce the emission intensity of its GDP by 20–25 % from the 2005 level by 2020. This paper attempts to find out if the Indian steel sector can help the country in fulfilling this commitment. The sector reduced its CO₂ emissions per ton of steel produced by 58% from 1994 to 2007. The study generates six scenarios for future projections which show that the sector can reduce its emission intensity by 12.5 % to 63 %. But going by the conservative estimates, the sector can reduce emission intensity by 30 % to 53 %. However, actual emissions will go up significantly in every case.     

Regulatory attitudes and environmental innovation in a model combining internal and external R&D

The extent to which environmental regulatory institutions are either ‘green’ or ‘brown’ impacts not just the intensity of regulation at any moment, but also the incentives for the development of new pollution-control technologies. We set up a strategic model of R&D in which a polluter can deploy technologies developed in-house, or license technologies developed by specialist outsiders (an ‘eco-industry’). Polluters exert R&D effort and may even develop redundant technologies to improve the terms on which they procure technology from outside. We find that, while regulatory bias has an ambiguous impact on the best-available technology, strategic delegation to systematically biased regulators can improve social welfare.     

Isolation and Characterization of a <Emphasis Type="Italic">Burkholderia</Emphasis> sp. USM (JCM15050) Capable of Producing Polyhydroxyalkanoate (PHA) from Triglycerides,Fatty Acids and Glycerols

A consortium of microorganisms from oil polluted wastewater sample was cultivated to promote polyhydroxyalkanoate (PHA) accumulation before subjecting the mixed cultures to sucrose density gradient ultracentrifugation. This resulted in the fractionation of the bacterial cells according to their physical features such as size, morphology and/or densities. An isolate was identified as Burkholderia sp. USM (JCM15050), which was capable of converting palm oil products [crude palm kernel oil (CPKO), palm olein (PO), palm kernel acid oil (PKAO), palm stearin (PS), crude palm oil (CPO), palm acid oil (PAO) and palm fatty acid distillate (PFAD)], fatty acids and various glycerol by-products into poly(3-hydroxybutyrate) [P(3HB)]. Up to 70 and 60 wt% of P(3HB) could be obtained when 0.5%(v/v) CPKO and glycerol was fed, respectively. Among the various fatty acids tested, lauric acid followed by oleic acid and myristic acid gave the best cell growth and PHA accumulation. Compared to Cupriavidus necator H16, the present isolate showed better ability to grow on and produce PHA from various glycerol by-products generated by the palm oil industry. This study demonstrated for the first time an isolate that has the potential to utilize palm oil and glycerol derivatives for the biosynthesis of PHA.     

Toxicology of benzyl alcohols: a QSAR analysis

There is an evidence that benzyl alcohols may exhibit toxicity via a radical mechanism. To test this possibility, we studied the toxicity of para substituted benzyl alcohols on rapidly dividing cancer cells (L1210 leukemia). This system has previously found utility in studying the apparent radical toxicity of a variety of phenols. However, no evidence could be found for an electronic effect and the cellular toxicity was associated primarily with hydrophobicity. Comparison of this quantitative structure-activity relationships (QSAR) with others for the reactions of benzyl alcohols in diverse systems provides insight into mechanisms of action. A QSAR for the interaction of benzyl alcohols with protozoa yields an equation that is dependent on both hydrophobicity and acidity of the OH group versus a mixture of bacteria and fungi, the critical dependence on hydrophobicity prevails with a small dependence on a resonance-stabilized, radical mediated electronic effect. The chloramphenicols provide an instructive example, where the radical mediated electronic effect overshadows the hydrophobic contribution to bacterial toxicity. These various QSAR for benzyl alcohols indicate that mechanisms of growth inhibition in vitro vary depending on cell/organism type, the strength of the bond and lability of the hydrogen, and the strength of the initiating radical reagent.     

Biodegradation of Natural Rubber and Natural Rubber Products by <Emphasis Type="Italic">Streptomyces</Emphasis> sp. Strain CFMR 7

The rubber degrading activity of Streptomyces sp. CFMR 7 whose whole genome sequence was recently determined was tested with non-vulcanized fresh latex and common vulcanized rubber products such as latex glove, latex condom and latex car tyre. The degradation activity was unequivocally demonstrated by scanning electron microscopy with respect to microbial colonization efficiency, disintegration of rubber material and biofilm formation after 3, 6 and 9 months of inoculation. Fourier transform infrared spectroscopy comprising the attenuated total reflectance analysis on these inoculated products revealed insights into the biodegradation mechanism of this strain whereby, a decrease in the number of cis -1,4 double bonds in the polyisoprene chain, the appearance of ketone and aldehyde groups formation indicating an oxidative attack at the double bond of rubber hydrocarbon. In the presence of strain Streptomyces sp. CFMR 7, gel permeation chromatography analysis revealed a significant shift of the molecular weight distribution to lower values. Clear decrease in the molecular weight was observed over 3, 6 and 9 months of cultivation on fresh latex samples compared to other vulcanized products. No shift in the molecular weight distribution was observed for non-inoculated control. These results clearly showed that Streptomyces sp. CFMR 7 was able to cleave the carbon backbone of poly (cis -1,4-isoprene). Although this strain was able to degrade both non-vulcanized and vulcanized rubber products, faster degradation was obtained with natural rubber and rubber products with low complexity.     

Fast removal of heavy metals from water and soil samples using magnetic Fe3O4 nanoparticles

Environmental Science and Pollution Research - Heavy metal discharge from anthropogenic sources on open soil surfaces and in natural water bodies poses serious environmental and health concerns. In...     

Community pressure for green behavior

The desire to avoid rousing community hostility may encourage firms to behave in an environmentally responsible manner. Firms may engage in corporate social responsibility (CSR) to maintain community support and/or to regain the support of a community where it has been lost. It has been conjectured that such ‘informal regulation’ could effectively replace formal intervention in some settings, and usefully complement it in others. We explore these conjectures with mixed results. Informal regulation is necessarily less efficient than a well-designed formal alternative and the pattern of green behavior induced by the threat of community hostility may increase or decrease welfare. The existence of community pressure may increase or decrease the optimal calibration of a formal intervention (in this case an environmental tax) and may complement or detract from the incentives generated by an optimally calibrated tax.