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The fast decay in PEM fuel cells of a highly active, high performance, but unstable Fe/N/C catalyst like our NC_Ar + NH3 follows a chemical, not an electrochemical, demetallation mechanism for its ORR active FeN4 sites in the catalyst micropores.

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.

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.

Abstract It is shown that the mechanism of parametric energy conversion—a non-linear phenomenon which is known to occur in all branches of physics—may play a fundamental role in energy conversion in biological structures. Parametric energy conversion means pumping of energy through the variation of an energy storing quantity (a parameter). In biological systems the energy storing parameter is the membrane itself, the structure and composition of which is varied by proceeding structure bound biochemical reactions. The principle of parametric energy conversion is introduced into a molecular kinetical model and three coupled differential equations are derived, which interconnect chemical, electrical and mechanical energy in biological structures. It is shown that they describe parametric pumping of energy. It is a particular mechanism, which is also found in the physical phenomenon of Bethenod. The mechanism is tested with the derivation and explanation of various important bioenergetical functions as special cases of parametric energy conversion, of ATP synthesis, the pumping of ions and molecules during active transport, the excitability of nerve membranes and the dynamics of oscillatory muscles. A new interpretation of the connection of structure and function in striated muscles is also derived and signal transformation in receptors discussed. It is suggested that parametric energy conversion may be the uniform basis of energy conversion in biological structures and that the path of bioenergetic evolution might have essentially followed the line marked by the characteristic properties of this flexible mechanism. The parametric hypothesis offers an elegant ordering scheme and reasonable explanation for evolution and function of a large variety of important bioenergetic mechanisms. In order to handle the intricate mechanism properly it would be necessary to give up the conventional, intuitive way of formulating and understanding biochemical mechanisms and to develop a new dimension of chemical thinking.

AbstractProtein–DNA interactions induce conformational changes in DNA such as B‐ to A‐form transitions at a local level. Such transitions are associated with a junction free energy cost at the boundary of two different conformations in a DNA molecule. In this study, we performed umbrella sampling simulations to find the free energy values of the B–A transition at the dinucleotide and trinucleotide level of DNA. Using a combination of dinucleotide and trinucleotide free energy costs obtained from simulations, we calculated the B/A junction free energy. Our study shows that the B/A junction free energy is 0.52 kcal mol−1 for the A‐philic GG step and 1.59 kcal mol−1 for the B‐philic AA step. This observation is in agreement with experimentally derived values. After excluding junction effects, we obtained an absolute free energy cost for the B‐ to A‐form conversion for all the dinucleotide steps. These absolute free energies may be used for predicting the propensity of structural transitions in DNA.

Sustainable aviation fuels (SAFs) can contribute reduce greenhouse gas emissions compared to conventional fuel. With the increasing SAFs demand, various generations of resources have been shifted from the 1st generation (oil crops), the 2nd generation (agricultural waste), to the 3rd generation (microalgae). Microalgae are the most suitable feedstock for jet biofuel production than other resources because of their productivity and capability to capture carbon dioxide. However, microalgae-based biofuel has a limitation of high freezing point. Recently, a jet biofuel derived from Euglena wax ester has been paying attention due to its low freezing point. Challenges still remain to enhance production yields in both upstream and downstream processes. Studies on downstream processes as well as techno-economic analysis on biofuel production using Euglena are highly limited to date. Economic aspects for the biofuel production will be ensured via valorization of industrial byproducts such as food wastes.

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.

AbstractMicroalgal biotechnology could generate substantial amounts of biofuels with minimal environmental impact if the economics can be improved by increasing the rate of biomass production. Chlorella kessleri was grown in a small‐scale raceway pond and in flask cultures with the entire volume, 1% (v/v) at any instant, periodically exposed to static magnetic fields to demonstrate increased biomass production and investigate physiological changes, respectively. The growth rate in flasks was maximal at a field strength of 10 mT, increasing from 0.39 ± 0.06 per day for the control to 0.88 ± 0.06 per day. In the raceway pond the 10 mT field increased the growth rate from 0.24 ± 0.03 to 0.45 ± 0.05 per day, final biomass from 0.88 ± 0.11 to 1.56 ± 0.18 g/L per day, and maximum biomass production from 0.11 ± 0.02 to 0.38 ± 0.04 g/L per day. Increased pigment, protein, Ca, and Zn content made the biomass produced with magnetic stimulation nutritionally superior. An increase in oxidative stress was measured indirectly as a decrease in antioxidant capacity from 26 ± 2 to 17 ± 1 µmol antioxidant/g biomass. Net photosynthetic capacity (NPC) and respiratory rate were increased by factors of 2.1 and 3.1, respectively. Loss of NPC enhancement after the removal of magnetic field fit a first‐order model well (R2 = 0.99) with a half‐life of 3.3 days. Transmission electron microscopy showed enlarged chloroplasts and decreased thylakoid order with 10 mT treatment. By increasing daily biomass production about fourfold, 10 mT magnetic field exposure could make algal oil cost competitive with other biodiesel feedstocks. Bioelectromagnetics 33:298–308, 2012. © 2011 Wiley Periodicals, Inc.

The initial biomass density had a significant effect on the growth behaviour of Leptolyngbya foveolarum HNBGU-001 in the batch culture. The test organism produced substantial amounts of biomass and lipids when allowed to grow at 40 °C and pH 8.0. The Placket-Burman design appropriately indicated the positive and negative influences of the tested nutrient factors on biomass and lipid productivities of L. foveolarum. Employing the Box-Behnken design of response surface methodology, the elevated concentrations of sulphate-S (300 mg/L) and carbonate-C (45.39 mg/L) but relatively low levels of phosphate-P (10 mg/L) and nitrate-N (375 mg/L) were identified as the optimal nutritional requirements of the test organism for the maximum lipid productivity (49.60 ± 0.70 mg/L/day) along with high lipid content (32.10 ± 0.40% dry cell weight) and biomass productivity (154.80 ± 3.60 mg/L/day). These maximized responses of biomass productivity, lipid content, and lipid productivity were respectively 2.8-, 2.4-, and 6.8-fold higher than their corresponding values under the unoptimized conditions. FAME analysis of lipids obtained from the test organism revealed some promising features for their use as algal biodiesel feedstock. Nonetheless, the test organism seems to have better potential than several other microalgae for use in biofuel production as it can give a high output of biomass as also lipids at elevated temperature prevalent in outdoor conditions of subtropical and tropical regions.