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The formation and decay of excited states of light‐harvesting bacteriochlorophyll (BChl) molecules and primary charge separation in reaction centres (RCs) of pigment‐protein complex B890 of the purple bacterium Chromatium minutissimum were studied as a function of excitation wavelength by means of picosecond absorbance difference spectroscopy. Selective excitation in the RC absorption band (at 800 nm) induced rapid bleaching of the absorption band of the RC BChl dimer (τ ∼ 1 ps) without absorption changes due to excited light‐harvesting BChl. It is concluded that excitation energy transfer from the BChl dimer of the RC to light‐harvesting BChl molecules is considerably slower than RC charge separation. Therefore, energy transfer from the light‐harvesting antenna to the RC in bacterial photosynthesis may be described as a ‘migration‐limited model’.

The increasing demand for lignocellulosic biomass for the production of biofuels provides value to vegetative plant tissue and leads to a paradigm shift for optimizing plant architecture in bioenergy crops. Plant height (PHT) is among the most important biomass yield components and is the focus of this review, with emphasis on the energy grasses maize (Zea mays) and sorghum (Sorghum bicolor). We discuss the scientific advances in the identification of PHT quantitative trait loci (QTLs) and the understanding of pathways and genes controlling PHT, especially gibberellins and brassinosteroids. We consider pleiotropic effects of QTLs or genes affecting PHT on other agronomically important traits and, finally, we discuss strategies for applying this knowledge to the improvement of dual-purpose or dedicated bioenergy crops.

Production of fuels and chemicals through microbial fermentation of plant material is a desirable alternative to petrochemical-based production. Fermentative production of biorenewable fuels and chemicals requires the engineering of biocatalysts that can quickly and efficiently convert sugars to target products at a cost that is competitive with existing petrochemical-based processes. It is also important that biocatalysts be robust to extreme fermentation conditions, biomass-derived inhibitors, and their target products. Traditional metabolic engineering has made great advances in this area, but synthetic biology has contributed and will continue to contribute to this field, particularly with next-generation biofuels. This work reviews the use of metabolic engineering and synthetic biology in biocatalyst engineering for biorenewable fuels and chemicals production, such as ethanol, butanol, acetate, lactate, succinate, alanine, and xylitol. We also examine the existing challenges in this area and discuss strategies for improving biocatalyst tolerance to chemical inhibitors.

Cells respond to environmental cues by modifying protein complexes in the nucleus to produce a change in the pattern of gene expression. In this article, we review techniques that allow us to visualize these protein interactions as they occur in living cells. The cloning of genes from marine organisms that encode fluorescent proteins provides a way to tag and monitor the intracellular behavior of expressed fusion proteins. The genetic engineering of jellyfish green fluorescent protein (GFP) and the recent cloning of a sea anemone red fluorescent protein (RFP) have provided fluorescent tags that emit light at wavelengths ranging from the blue to the red spectrum. Several of these color variants can be readily distinguished by fluorescence microscopy, allowing them to be used in combination to monitor the behavior of two or more independent proteins in the same living cell. We describe the use of this approach to examine where transcription factors are assembled in the nucleus. To demonstrate that these labeled nuclear proteins are interacting, however, requires spatial resolution that exceeds the optical limit of the light microscope. This degree of spatial resolution can be achieved with the conventional light microscope using the technique of fluorescence resonance energy transfer (FRET). The application of FRET microscopy to detect the interactions between proteins labeled with the color variants of GFP and the limitations of the FRET approach are discussed. The use of different-color fluorescent proteins in combination with FRET offers the opportunity to study the complex behavior of key regulatory proteins in their natural environment within the living cell.

Implementing a circular economy aimed at reusing resources is becoming increasingly important for industry. Microalgae fit within a circular economy by being able to bioremediate nutrient waste and as a source of biomass for several commercial applications. Here, we report a novel validation of a circular economy concept using microalgae at a relevant industrial scale with a new two-phase process. During the first phase biomass was grown autotrophically, biomass was then concentrated using membrane technology for the second phase where mixotrophic conditions were applied to boost growth further. Microalgae cultures were able to grow (13.8 g/L), uptake and bioremediate nutrients (Nitrogen > 134 mg/L/day) from an anaerobic digestion side-stream (digestate), obtaining high quality microalgae biomass (>45% protein content) suitable for use as animal feed, closing the circular economy loop for industrial applications.

Gαi3 is found both on the plasma membrane and on Golgi membranes. Calnuc, an EF hand protein, binds both Gαi3 and Ca 2+ and is found both in the Golgi lumen and in the cytoplasm. To investigate whether Gαi3 binds calnuc in living cells and where this interaction takes place we performed fluorescence resonance energy transfer (FRET) analysis between Gαi3 and calnuc in COS-7 cells expressing Gαi3-yellow fluorescent protein (YFP) and calnuc-cyan fluorescent protein (CFP). The tagged proteins have the same localization as the endogenous, nontagged proteins. When Gαi3-YFP and calnuc-CFP are coexpressed, a FRET signal is detected in the Golgi region, but no FRET signal is detected on the plasma membrane. FRET is also seen within the Golgi region when Gαi3 is coexpressed with cytosolic calnuc(ΔN2–25)-CFP lacking its signal sequence. No FRET signal is detected when Gαi3(ΔC12)-YFP lacking the calnuc-binding region is coexpressed with calnuc-CFP or when Gαi3-YFP and calnuc(ΔEF-1,2)-CFP, which is unable to bind Gαi3, are coexpressed. Gαi3(G2AC3A)-YFP lacking its lipid anchors is localized in the cytoplasm, and no FRET signal is detected when it is coexpressed with wild-type calnuc-CFP. These results indicate that cytosolic calnuc binds to Gαi3 on Golgi membranes in living cells and that Gαi3 must be anchored to the cytosolic surface of Golgi membranes via lipid anchors for the interaction to occur. Calnuc has the properties of a Ca 2+ sensor protein capable of binding to and potentially regulating interactions of Gαi3 on Golgi membranes.

Lipase‐catalyzed transesterification of triglycerides and alcohols to obtain biodiesel is an environmentally friendly and sustainable route for fuels production since, besides proceeding in mild reaction conditions, it allows for the use of low‐cost feedstocks that contain water and free fatty acids, for example non‐edible oils and waste oils. This review article reports recent advances in the field and focus in particular on a major issue in the enzymatic process, the inactivation of most lipases caused by methanol, the preferred acyl acceptor used for alcoholysis. The recent results about immobilization of enzymes on nano‐materials and the use of whole‐cell biocatalysts, as well as the use of cell‐surface display technologies and metabolic engineering strategies for microbial production of biodiesel are described. It is discussed also insight into the effects of methanol on lipases obtained by modeling approaches and report on studies aimed at mining novel alcohol stable enzymes or at improving robustness in existing ones by protein engineering.

Abstract We evaluated three Integrated Assessment Models (IAMs: IGSM, MERGE, MiniCAM) by: (i) comparing their global Primary Energy year-2000 initializations and projections for 2010 and 2015 to historical data; (ii) mapping their CO2 emissions projections against observations; and (iii) examining model-output diagnostics. The IAMs underestimated historical primary energy consumption and initial/projected CO2 emissions in both reference and stabilization scenarios (particularly for combustion fuels) but overestimated usage of non-biomass renewables, causing underestimates of future CO2 emissions that, for the stabilization scenarios, are wildly optimistic. Mitigation technology breakdowns in the policy scenarios vary enormously across IAMs, suggesting that confidence in their projections might be misplaced, or that options for mitigation have greater scope than is supposed. Most increases in carbon-free technologies in the stabilization scenarios are already captured in the reference cases. Energy-conversion efficiencies in electricity generation improve over time, but, (except for gas-powered generation in IGSM), efficiencies in the policy scenarios are less than in the reference. Electrification results diverge widely: IGSM has little change over the 21st century, while MiniCAM and MERGE have major electrification increases in their policy scenarios. We suggest: 1) comprehensive model output suitable for secondary analysis should be more readily available; 2) directly comparable reference and policy-driven mitigation scenarios are essential for assessing mitigation measures; 3) model validation using historical, source-specific energy data is crucial for assessing model credibility; 4) separation of mitigation contributions into no-policy and policy-driven amounts is needed to assess the effectiveness of mitigation policies; and 5) detailed inter-model comparisons can provide important insights into model credibility.