Tween 20 and Its Major Free Fatty Acids as Carbon Substrates for the Production of Polyhydroxyalkanoates in Pseudomonas aeruginosa ATCC 27853

The ability of Pseudomonas aeruginosa ATCC 27853 to grow and synthesize polyhydroxyalkanoates (PHAs) using Tween 20 as the sole carbon source was investigated. Tween 20 could support cell growth and PHA production. The polymer produced from Tween 20 was compared with those produced from its major free fatty acids components: lauric (C₁₂), myristic (C₁₄), and palmitic (C₁₆) acids. Gas-chromatographic analysis of methanolyzed samples and ¹³C-Nuclear Magnetic Resonance (NMR) showed that the PHAs obtained are composed of even carbon atoms 3-hydroxyalkanoates ranging from C₆ to C₁₄, with C₈ and C₁₀ as the predominant components. The nature of the carbon sources used had little influence on the composition, but was found to be important in determining the average molecular weight, shorter chain fatty acids yielding higher molecular weight products. Fast Atom Bombardment-Mass Spectrometry (FAB-MS) of partially pyrolyzed samples, coupled to statistical analysis, showed that these PHAs are random copolymers.     

工会与可持续发展

政府、工业 (包括工会 )和团体必须全部参与改变不可持续发展的生产与消费结构 .更多地了解工会独特的性质和可持续发展不同元素之间的联系,可以导致进行改变的更有效的行动和更坚固的伙伴关系 .可持续发展所需要的经济和社会改组,给工人总是面对的物质生存和经济生存之间的对立的选择增加了一个新的方面 .     

Assessment of compost dosage in farmland through ecotoxicological tests

A research project was carried out to evaluate ecotoxicological effects of mature compost addition to agricultural soil, using a battery of ecotoxicological tests. The following species were selected: plant of Lepidium sativum, earthworm Eisenia foetida, aquatic crustacean Daphnia magna and bacteria Vibrio fischeri. The tests were classified as “direct tests” using solid compost samples and “indirect tests” using compost leaching test eluate. The direct bioassays were performed using compost added to artificial soil in concentrations ranging from 2.5 to 100 % (w/w); the indirect ones considered compost eluate, added to a standard solution in the same concentrations used in the direct tests. Both tests aimed at obtaining the ecotoxicological parameters (LC₅₀ and EC₅₀). These values were then utilized to implement the Species Sensitivity Distribution (SSD) analysis and extrapolate the Hazard Concentration (HC), a useful threshold to preserve the biodiversity of agricultural ecosystems. Results indicated an increase in compost toxicity with greater compost concentrations; in particular, for direct tests compost dosage below 10 % showed low toxicity, while for indirect ones the toxicity was higher. Furthermore, SSD analysis showed a Hazardous Concentration (HC₅) for direct bioassays of 3.5 % and for indirect of 14 %.     

Managing Excessive Methanogenesis During ERD/ISCR Remedial Action

Excessive production of methane has been observed at some remediation sites following the addition of organic hydrogen donors such as (emulsified) oils/lecithin, sugars, and conventional carbon + zero‐valent iron (ZVI) amendments. This is due to the fact that methanogens are commonly the most ubiquitous indigenous microbes in anoxic aquifer settings, and, under enriched environmental conditions, methanogens replicate every one to two hours (whereas Dehalococcoides spp., e.g., double in 24–48 hr). Hence, methanogens often bloom and dominate the microbial ecosystem following the addition of remedial amendments, thereby liberating large amounts of methane gas. There are at least three important consequences of this response:

1. By utilizing hydrogen, the methanogens compete with dechlorinating microbes, thus making inefficient use of the remedial amendment (just 20 ppm methane in groundwater represents an approximate 30 percent “waste” of added fermentable substrate (i.e., hydrogen donor)—this is a common and tangible detriment);
2. Methanogens can methylate heavy metals and their rapid growth consumes alkalinity, while generating acidity, thereby facilitating multiple potential mechanisms for creating secondary contaminant issues (i.e., arsenic plumes); and
3. Elevated methane concentrations can exceed current and pending regulations of <10 to <28 ppm methane in groundwater and/or 0.5 percent by volume methane in soil gas (e.g., 10 percent of the lower explosive limit) and/or indoor air (methane is flammable between 5 percent and 15 percent by volume) and this will induce migration of contaminant vapors potentially causing indoor air issues.

Considering the recent guidelines for indoor air published by the US Environmental Protection Agency, it is increasingly important to prevent excessive methanogenesis associated with remedial actions. From a regulatory perspective, public safety issues are paramount; from a property re‐use or real estate (brownfield) developers’ perspective, project delays are costly and can jeopardize an entire program. The use of antimethanogenic compounds as inhibitors of protein biosynthesis and the activity of enzyme systems unique to Archaea (i.e., methanogens) during in situ remedial action can improve contaminant removal while offering safer, more efficacious treatment, simply by impeding the methanogenic bacteria's ability to proliferate and out compete desired bacterial communities (e.g., Dehalococcoides spp.). ©2016 Wiley Periodicals, Inc.     

Validation of a questionnaire about the perception of occupational biohazard in Spanish companies

Objectives. The aim of this work was to develop, validate and test a new questionnaire to assess the biological risk in workers with intentional or unintentional exposure to biological agents. Methods. A questionnaire including 34 questions was developed to study the perception of workers against occupational biohazard. Content Validity Index (CVI) and Content Validity Ratio (CVR) were calculated for the analysis of content validity. A pilot study was carried out with 60 workers from 17 companies performing analysis of Cronbach's α to assess the internal consistency or reliability. Results. A total of 518 workers from 51 Spanish companies in which there is exposure to biological agents participated in the study yielding a response rate of 90%. The final questionnaire obtained a Cronbach's α > 0.759 with a stable test–retest result. The questionnaire validation demonstrates that it could be used to evaluate the biological risks and help the prevention of occupational accidents and diseases. Discussion. This study has validated the need to evaluate worker's perception against occupational risks, as well as the application of prevention methods and protective equipment. It is a first step towards developing an occupational biohazards assessment method including all the requirements set by the European Health and Safety Strategy 2013–2020.     

Revealing the economic channels of natural impacts: an extended input–output subsystems application to GHG gases and water use

While a small set of economic activities generates most of the direct environmental burdens, the complexity of connections within an economic system requires consideration of the effects caused by the interdependences between its different agents. To date, however, the input–output (I–O) subsystems literature has been limited to uncovering the intersectoral linkages of direct and indirect environmental impacts within an economy and the connections between sectors and private consumption have thus not attracted much attention. This paper proposes an I–O subsystems model that endogenously incorporates not only production sectors but also household consumption to capture the entire channel of environmental impacts. The empirical application focuses on carbon dioxide equivalent (CO₂-eq.) emissions and water use associated with production sectors and households defined in the I–O table for a Spanish region, Extremadura. The results highlight the key role of the effects induced by private consumption on the environmental burdens of services.     

Detecting Insect Pollinator Declines on Regional and Global Scales

Recently there has been considerable concern about declines in bee communities in agricultural and natural habitats. The value of pollination to agriculture, provided primarily by bees, is >$200 billion/year worldwide, and in natural ecosystems it is thought to be even greater. However, no monitoring program exists to accurately detect declines in abundance of insect pollinators; thus, it is difficult to quantify the status of bee communities or estimate the extent of declines. We used data from 11 multiyear studies of bee communities to devise a program to monitor pollinators at regional, national, or international scales. In these studies, 7 different methods for sampling bees were used and bees were sampled on 3 different continents. We estimated that a monitoring program with 200–250 sampling locations each sampled twice over 5 years would provide sufficient power to detect small (2–5%) annual declines in the number of species and in total abundance and would cost U.S.$2,000,000. To detect declines as small as 1% annually over the same period would require >300 sampling locations. Given the role of pollinators in food security and ecosystem function, we recommend establishment of integrated regional and international monitoring programs to detect changes in pollinator communities. Detección de Declinaciones de Insectos Polinizadores a Escalas Regional y Global     

Cocoa Intensification Scenarios and Their Predicted Impact on CO<Subscript>2</Subscript> Emissions,Biodiversity Conservation,and Rural Livelihoods in the Guinea Rain Forest of West Africa

The Guinean rain forest (GRF) of West Africa, identified over 20 years ago as a global biodiversity hotspot, had reduced to 113,000 km² at the start of the new millennium which was 18% of its original area. The principal driver of this environmental change has been the expansion of extensive smallholder agriculture. From 1988 to 2007, the area harvested in the GRF by smallholders of cocoa, cassava, and oil palm increased by 68,000 km². Field results suggest a high potential for significantly increasing crop yields through increased application of seed-fertilizer technologies. Analyzing land-use change scenarios, it was estimated that had intensified cocoa technology, already developed in the 1960s, been pursued in Cote d’Ivoire, Ghana, Nigeria and Cameroon that over 21,000 km² of deforestation and forest degradation could have been avoided along with the emission of nearly 1.4 billion t of CO₂. Addressing the low productivity of agriculture in the GRF should be one of the principal objectives of REDD climate mitigation programs.