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.     

A new apparatus to enhance the rate of gas hydrate formation: Application to capture of carbon dioxide

A new apparatus employing a modular, mechanically agitated gas-inducing crystallizer is used to demonstrate the capture of CO₂ via hydrate crystallization. The crystallizer enhances the contact of hydrate forming gases with water and thus the rate of hydrate crystallization increases. Flue gas (CO₂/N₂) and fuel gas (CO₂/H₂) mixtures were used to represent post- and precombustion capture. A comparison between the rates of hydrate formation in different crystallizers is presented by defining a metric called the normalized rate of hydrate formation. The gas uptake and the separation efficiency for the fuel and flue gas mixtures were found to be greater compared to the results obtained in a smaller scale stirred tank reactor (Kumar et al., 2009c, Linga et al., 2008). The gas uptake and CO₂ recovery for flue gas mixture in the presence of THF obtained in this work was higher than that reported in the literature with tetra-n-butyl ammonium bromide and tetra-n-butyl ammonium fluoride (Fan et al., 2009, Li et al., 2009). Although hydrate crystallization is able to capture CO₂, the power required for mechanical agitation was found to be very significant. If the hydrate process is to be used industrially then hydrate crystallization must be carried out without mechanical agitation.     

Application of enzyme-linked immunosorbent assay analysis for determination of monensin in environmental samples

There is growing concern that antibiotic use in livestock production is contributing to contamination of soil and aquatic environments. Monensin, a polyether ionophore antibiotic, accounts for approximately 13% of total subtherapeutic livestock antibiotic usage in the USA and has been widely detected in aquatic environments. Due to insufficient ultraviolet absorbance, liquid chromatography analysis of monensin in environmental samples is limited to equipment with mass spectrometry (e.g., liquid chomatography-mass spectrometry [LC-MS]). However, LC-MS equipment is costly, and extensive sample preparation and clean-up is often required. Rapid, low-cost analytical techniques are needed to monitor for monensin residues in the environment. In this study, a commercially available enzyme-linked immunosorbent assay (ELISA) for detecting monensin in animal feed extracts was evaluated for determination of monensin in water, soil, and manure. The monensin ELISA was highly sensitive, with limits of detection and quantification at 1.5 and 3.0 microg L(-1), respectively. Recovery of monensin in spiked water samples was approximately 100%. Cross-reactivity was not observed with similar polyether ionophores, tetracyclines, macrolides, or sulfonamides. Concentrations of monensin using ELISA were greater than concentrations measured with LC-MS. This is attributed to cross-reactivity of the monensin ELISA toward structurally similar monensin compounds, such as factors (slight naturally produced structural variants) and metabolites. Results from this study showed that ELISA can be a reliable, rapid, and low-cost alternative to LC-MS analysis of environmental samples.     

Environmental impacts and use of brominated flame retardants in electrical and electronic equipment

Management of waste electrical and electronic equipment (WEEE) or e-waste is becoming a major issue as around 20–50 million tons of such waste is generated worldwide and increasing at a higher rate than other solid waste streams. Electrical and electronic equipment (EEE) contains over 1,000 materials of which brominated flame retardants (BFRs) such as polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) have been the target of the regulators forcing manufacturers to adopt halogen-free flame retardants. As far as these alternatives are concerned, key consideration should be its performance during the whole life cycle through design, use and end-of-life management. The global halogen-free flame retardant movement has reached a point of no return. The most important issue as far as the environment is concerned, for which the transformation to halogen-free retardants was initially targeted, is to make sure that life span of the EEE using the alternatives to BFRs is not shortened thereby resulting in unforeseen increases in e-waste to deal with. The aim of this article is to investigate the environmental issues and current developments related to the use of BFRs in EEE manufacture. It describes the sources, toxicity and human exposure of BFRs, EOL management such as recycling and thermal treatments, exposure of BFRs from e-waste processing facilities and the environment around them and examines the developments and feasibility of the alternatives to BFR in EEE manufacture.     

Degradation of anionic surfactants during drying of UASBR sludges on sand drying beds

Anionic surfactant (AS) concentrations in wet up-flow anaerobic sludge blanket reactor (UASBR) sludges from five sewage treatment plants (STPs) were found to range from 4480 to 9233mgkg(-1)drywt. (average 7347mgkg(-1)drywt.) over a period of 18 months. After drying on sand drying beds (SDBs), AS in dried-stabilized sludges averaged 1452mgkg(-1)drywt., a reduction of around 80%. The kinetics of drying followed simple first-order reduction of moisture with value of drying constant (k(d))=0.051d(-1). Reduction of AS also followed first-order kinetics. AS degradation rate constant (k(AS)) was found to be 0.034d(-1) and half-life of AS as 20 days. The order of rates of removal observed was k(d)>k(AS)>k(COD)>k(OM) (drying >AS degradation>COD reduction>organic matter reduction). For the three applications of dried-stabilized sludges (soil, agricultural soil, grassland), values of risk quotient (RQ) were found to be <1, indicating no risk.     

Analytic hierarchy process helps select site for limestone quarry expansion in Barbados

Site selection is a key activity for quarry expansion to support cement production, and is governed by factors such as resource availability, logistics, costs, and socio-economic-environmental factors. Adequate consideration of all the factors facilitates both industrial productivity and sustainable economic growth. This study illustrates the site selection process that was undertaken for the expansion of limestone quarry operations to support cement production in Barbados. First, alternate sites with adequate resources to support a 25-year development horizon were identified. Second, technical and socio-economic-environmental factors were then identified. Third, a database was developed for each site with respect to each factor. Fourth, a hierarchical model in analytic hierarchy process (AHP) framework was then developed. Fifth, the relative ranking of the alternate sites was then derived through pair wise comparison in all the levels and through subsequent synthesizing of the results across the hierarchy through computer software (Expert Choice). The study reveals that an integrated framework using the AHP can help select a site for the quarry expansion project in Barbados.     

Nitrate reductase, arginine deaminase, urease and dehydrogenase activities in natural soil (ridges with forest) and in cotton soil after acetamiprid treatments

Soil enzymes are indicators of microbial activities in soil and are often considered as an indicator of soil health and fertility. They are very sensitive to the agricultural practices, pH of the soil, nutrients, inhibitors and weather conditions. To understand the effect of an insecticide, acetamiprid (IUPAC Name: (E)-N1-[(6-chloro-3-pyridyl) methyl]-N2-cyano-N1-methyl acetamidine) on different soil enzyme activities, the experiments were conducted for three consecutive years (2003--2005) at control and cotton experimental fields of Indian Agricultural Research Institute (IARI) and natural area (ridges with forest) in Delhi. The combined results for all three years were presented here to understand the impact of acetamiprid on soil enzyme activities. Acetamiprid was applied three times in one crop season after 41, 48 and 73 days of sowing, to control the pest. Soil of treated fields was analyzed for insecticide residues immediately after first insecticide treatment and thereafter at definite period. The residues of acetamiprid in experimental soil was varied from 0.30+/-0.13 to 22.67+/-0.2 microg g(-1)d.wt. soil, during the crop period of 2003. The insecticide residues for 2004 ranged between 0.59+/-0.38 and 13.42+/-0.71 microg g(-1)d.wt. soil and for 2005 it ranged between 0.48+/-0.22 and 19.81+/-0.33 microg g(-1)d.wt. soil. An average half life of acetamiprid in our treated field was 11.2+/-1.7 days for all three years. Similarly, the soil from natural area and control were also tested for insecticide residues. No detectable insecticide residues had been found. Soil from three localities i.e. natural, control and experimental fields were tested for different enzyme activities. Nitrate reductase, arginine deaminase, urease and dehydrogenase activities were high in natural soil in comparison to control soil and insecticide treated soil in all three experimental years. At the same time, nitrate reductase activity was all time low in acetamiprid treated soil. Acetamiprid had inhibitory effects on nitrate reductase, arginine deaminase and urease activities. After first treatment (43 days after crop sowing), nitrate reductase (41%), arginine deaminase (22%) and urease (35%) activities were declined. Dehydrogenase activity increased to 22% after first insecticide application. Enzyme activities were recovered at the end of each crop season. Therefore, it can be attributed that agricultural practices, weather conditions and use of acetamiprid might be responsible for the different level of enzyme activities in soil.     

Management of root knot nematode on tomato through application of fungal antagonists, Acremonium strictum and Trichoderma harzianum

Management of root knot nematode disease infecting tomato, by the use of fungal bioagents Acremonium strictum and Trichoderma harzianum isolated from egg masses of M. incognita infecting tomato has been carried out. The rhizosphere and rhizoplane of root knot nematode infested tomato revealed consistent association of Acremonium strictum. In the present study A. strictum and other fungal bioagents viz. Aspergillus niger, Paecilomyces lilacinus, Rhizoctonia solani and Trichoderma harzianum isolated earlier from egg-masses of M. incognita, identified and maintained have been investigated through in-vitro and in-vivo trials for their potentiality against M. incognita. Out of the above, isolated mycoflora A. niger was identified to be toxic against M. incognita while A. strictum and T. harzianum was found to possess both egg parasitic or opportunistic and toxic properties. A field trial with all the above fungal bioagents both alone and together showed significant promising performance by the dual treatment of A. strictum and T. harzianum in improving the health of the tomato plant with a remarkable reduction in M. incognita population.     

Occurrence and fate of polycyclic musks in wastewater treatment plants in Kentucky and Georgia, USA

Wastewater treatment plants (WWTPs) are a potential of source of polycyclic musks in the aquatic environment. In this study, contamination profiles and mass flow of polycyclic musks, 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[gamma]-2-benzopyran (HHCB), 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene (AHTN), and HHCB-lactone (oxidation product of HHCB), in two WWTPs, one located in Kentucky (Plant A, rural area) and the other in Georgia (Plant B, urban), USA, were determined. HHCB, AHTN and HHCB-lactone were detected in the influent, effluent, and sludge samples analyzed. The concentrations in wastewater samples varied widely, from 10 to 7,030 ng/l, 13 to 5,400 ng/l, and 66 to 790 ng/l, for HHCB, AHTN, and HHCB-lactone, respectively. Sludge samples contained HHCB at <0.02-36 microg/g dry weight, AHTN at <0.02-7.2 microg/g dry weight, and HHCB-lactone at <0.05-17 microg/g dry weight. Based on the daily flow rates and mean concentrations of polycyclic musks, the estimated discharge of total polycyclic musks to the rivers was 21 g/day from Plant A and 31 g/day from Plant B. Mass balance analysis suggested that only 30% of HHCB and AHTN entering the plants was accounted for in the effluent and the sludge. Removal efficiencies of HHCB and AHTN in the two WWTPs ranged from 72% to 98%. In contrast, HHCB-lactone concentrations increased following the treatment. Concentrations of polycyclic musks in sludge were on the order of several parts per million. Incineration of sludge at one plant reduced the concentration of polycyclic musks.     

Flood proneness and coping strategies: the experiences of two villages in Bangladesh

This paper explores peoples' indigenous survival strategies and assesses variations in people's ability to cope with floods in two flood‐prone villages in Bangladesh. It reveals that people continuously battle against flood vulnerability in accordance with their level of exposure and abilities, with varied strategies employed at different geophysical locations. The paper reports that people in an area with low flooding and with better socioeconomic circumstances are more likely to cope with impacts compared to people in areas with high and sudden flooding. Similarly, households' ability to cope varies depending on people's socioeconomic conditions, such as education, income and occupation. Although floods in Bangladesh generate socioeconomic misery and cause damage to the environment, health and infrastructure, people's indigenous coping strategies have helped them to reduce significantly their vulnerability. Such flood‐mitigating strategies should be well recognised and emphasised further via proper dissemination of information through an early‐warning system and subsequently external assistance.