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New transparent optodes for life-time based microscopic imaging of O₂ were developed by spin-coating a μm-thin layer of a highly luminescent cyclometalated iridium(III) coumarin complex in polystyrene onto glass cover slips. Compared to similar thin-film O₂ optodes based on a ruthenium(II) polypyridyl complex or a platinum(II) porphyrin, the new planar sensors have i) higher brightness allowing for much shorter exposure times and thus higher time resolution, ii) more homogeneous and smaller pixel to pixel variation over the sensor area resulting in less noisy O₂ images, and iii) a lower temperature dependency simplifying calibration procedures. We used the new optodes for microscopic imaging of the spatio-temporal O₂ dynamics at the base of heterotrophic biofilms in combination with confocal imaging of bacterial biomass and biofilm structure. This allowed us to directly link biomass distribution to O₂ distribution under both steady state and non-steady state conditions. We demonstrate that the O₂ dynamics in biofilms is governed by a complex interaction between biomass distribution, mass transfer and flow that cannot be directly inferred from structural information on biomass distribution alone.

Proton nuclear magnetic resonance (NMR) spectroscopy was used to follow glucose metabolism in Crithidia luciliae. Parasites were grown aerobically and anaerobically in culture, with glucose as the major carbon source and 1H NMR spectra were acquired for the cell free medium. The 1H NMR resonances of metabolites utilised and produced during cell growth were identified by difference spectroscopy, and quantitated from standard curves using 3-trimethylsilyl propionate-2,2,3,3-d4 sodium salt as an internal standard. The major metabolites produced by C. luciliae grown aerobically on 8 mM glucose were succinate, pyruvate, acetate and ethanol, in final concentrations in the media when the cells entered stationary phase of 8.5 +/- 0.5, 5.0 +/- 0.3, 2.1 +/- 0.2 and 2.5 +/- 0.6 mM, respectively. The production of succinate and pyruvate, but not acetate and ethanol, followed closely the growth curve of the parasites. Succinate was also measured enzymically and glucose using an autoanalyser. In both cases the results correlated well with the NMR data. The amounts of end products formed were greater than could be accounted for by the utilisation of glucose or any other metabolite observable in the 1H NMR spectra. There was approximately one extra atom of carbon for each molecule of succinate formed, supporting the view that succinate is produced via phosphoenolpyruvate carboxykinase and carbon dioxide fixation. Anaerobically the same major metabolites were produced, but with a decreased ratio of succinate to acetate and ethanol. The formation of glycerol from glucose was not observed under these conditions.

Abstract New exogenous cis,cis-muconic acid biosynthetic pathway genes were expressed in Saccharomyces cerevisiae. The xylose isomerase gene from Bacteroides valgutus and pentose phosphate pathway genes from S. cerevisiae were overexpressed in the yeast strain. The strain was further modified by the overexpression of gene Aro1 (with a stop codon of AroE) and a feedback-resistant Aro4opt mutant gene from S. cerevisiae. Under oxygen-limited conditions, it produced 65 mg/L cis,cis-muconic acid from xylose. Co-fermentation of 88 g/L glucose and 50 g/L xylose generated 54 g/L ethanol and 248 mg/L cis,cis-muconic acid. Under aerobic conditions, muconic acid titer reached 424 mg/L. With the supplement of 1 g/L catechol, 1286 mg/L muconic acid was produced. Fermentation of an oil palm empty fruit bunch hydrolysate resulted in 31.3 g/L ethanol and 53.4 mg/L muconic acid. This is the first report on the production of muconic acid from lignocellulosic biomass hydrolysate using a recombinant xylose-fermenting yeast.

A better understanding of public perceptions, attitude and behavior in relation to climate change will provide an important foundation for government׳s policy-making, service provider׳s guideline development and the engagement of local communities. The purpose of this study was to assess the perception towards climate change, behavior change, mitigation and adaptation measures issued by the central government among the health professionals in the Centres for Disease Control and Prevention (CDC) in China.In 2013, a cross-sectional questionnaire survey was undertaken among 314 CDC health professionals in various levels of CDC in Shanxi Province, China. Descriptive analyses were performed.More than two thirds of the respondents believed that climate change has happened at both global and local levels, and climate change would lead to adverse impacts to human beings. Most respondents (74.8%) indicated the emission of greenhouse gases was the cause of climate change, however there was a lack of knowledge about greenhouse gases and their sources. Media was the main source from which respondents obtained the information about climate change. A majority of respondents showed that they were willing to change behavior, but their actions were limited. In terms of mitigation and adaptation measures issued by the Chinese Government, respondents׳ perception showed inconsistency between strategies and relevant actions. Moreover, although the majority of respondents believed some strategies and measures were extremely important to address climate change, they were still concerned about economic development, energy security, and local environmental protection.There are gaps between perceptions and actions towards climate change among these health professionals. Further efforts need to be made to raise the awareness of climate change among health professionals, and to promote relevant actions to address climate change in the context of the proposed policies with local sustainable development.

AbstractThe recombinant Escherichia coli B strain KO11, containing chromosomally‐integrated genes for ethanol production, was developed for use in lignocellulose‐to‐ethanol bioconversion processes but suffers from instability in continuous culture and a low ethanol tolerance compared to yeast. Here we report the ability cell immobilization to improve its phenotypic stability and ethanol tolerance during continuous culture on a 50 g/L xylose feed. Experiments conducted in a vertical tubular fermentor operated as a liquid‐fluidized bed with the cells immobilized on porous glass microspheres were compared to control experiments in the same reactor operated as a chemostat without the support particles. Without cell immobilization the ethanol yield fell sharply following start‐up, declining to 60% of theoretical after only 8–9 days of continuous fermentation. While immobilizing the cells did not prevent this decline, it delayed its onset and slowed its rate. With immobilization, a stable high ethanol yield (>85%) was maintained for at least 10 days, thereafter declining slowly, but remaining above 70% even after up to 40 days of fermentation. The ethanol tolerance of E. coli KO11 cells was substantially increased by immobilization on the glass microspheres. In ethanol tolerance tests, immobilized cells released from the microspheres had survival rates 2.3‐ to 15‐fold higher than those of free cells isolated from the same broth. Immobilization is concluded to be an effective means of increasing ethanol tolerance in E. coli KO11. While immobilization was only partially effective in combating its phenotypic instability, further improvements can be expected following optimization of the immobilization conditions. Biotechnol. Bioeng. 2008;100: 627–633. © 2008 Wiley Periodicals, Inc.