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Abstract: Waste papers (newspaper, office paper, magazines and cardboard in this study) with 50–73% (w/w oven dry weight) carbohydrate contents have considerable potential as raw materials for bioethanol production. A particle size reduction step of wet blending prior to enzymatic hydrolysis of newspaper was found to increase the glucan conversion efficiency by up to 10%. High-solids loading hydrolysis at 15% (w/w) of four types of paper using two enzyme alternatives, Celluclast 1.5L supplemented with Novozyme 188 and Cellic Ctec 1 (Novozymes A/S, Demark), at various enzyme concentrations were successfully performed in a lab-scale overhead-stirred reactor. This work has identified the relative saccharification performance for the four types of paper and shows office paper and cardboard to be more suitable for producing bioethanol than newspaper or magazine paper. The experimental data were also very well described by a modified, simple three parameter glucan and xylan hydrolysis model. These findings provide the possibility for incorporating this validated kinetic model into process designs required for commercial scale bioethanol production from waste paper resources. [Copyright &y& Elsevier]

Abstract: This study uses Life Cycle Assessment (LCA) to assess the environmental profiles and greenhouse gas (GHG) emissions for bioethanol production from waste papers and to compare them with the alternative waste management options of recycling or incineration with energy recovery. Bioethanol production scenarios both with and without pre-treatments were conducted. It was found that an oxidative lime pre-treatment reduced GHG emissions and overall environmental burdens for a newspaper-to-bioethanol process whereas a dilute acid pre-treatment raised GHG emissions and overall environmental impacts for an office paper-to-bioethanol process. In the comparison of bioethanol production systems with alternative management of waste papers by different technologies, it was found that the environmental profiles of each system vary significantly and this variation affects the outcomes of the specific comparisons made. Overall, a number of configurations of bioethanol production from waste papers offer environmentally favourable or neutral profiles when compared with recycling or incineration. [Copyright &y& Elsevier]

Presents an in vitro study of membrane protein folding. Processes involved in protein folding; Impact of intermolecular forces on membrane protein folding; Mutagenesis of protein folding.

Presents evidence that the stored curvature elastic stress in the lipid membrane's monolayer modulates the activity of CTP:phosphocholine cytidyltransferase. Role of a physical feedback signal in the control of membrane lipid synthesis.

Discusses the regulation of folding and assembly of the membrane protein bacteriorhodopsin by intermolecular forces with the lipid bilayer. Analysis of lipid systems; Kinetic phases associated with refolding; Rate-limiting steps in folding.

A largevariety of data exists on lipid phase behavior; however,it is mostly in nonbuffered systems over nonbiological temperatureranges. We present biophysical data on lipid mixtures of dioleoylphosphatidylcholine(DOPC), dioleoylphosphatidylethanolamine (DOPE), and lysophosphatidylcholine(LysoPC) examining their behaviors in excess water and buffer systemsover the temperature range 4–34 °C. These mixtures arecommonly used to investigate the effects of spontaneous curvatureon integral membrane proteins. Using small-angle X-ray scattering(SAXS) and 31P NMR, we observed lamellar and vesicle phases,with the buffer causing an increase in the layer spacing. Increasingamounts of DOPE in a DOPC bilayer decreased the layer spacing of themesophase, while the opposite trend was observed for increasing amountsof LysoPC. 31P static NMR was used to analyze the DOPC:LysoPCsamples to investigate the vesicle sizes present, with evidence ofvesicle budding observed at LysoPC concentrations above 30 mol %.NMR line shapes were fitted using an adapted program accounting forthe distortion of the lipids within the magnetic field. The distortionof the vesicle, because of magnetic susceptibility, varied with LysoPCcontent, and a discontinuity was found in both the water and buffersamples. Generally, the distortion increased with LysoPC content;however, at a ratio of DOPC:LysoPC 60:40, the sample showed a levelof distortion of the vesicle similar to that of pure DOPC. This impliesan increased flexibility in the membrane at this point. Commonly,the assumption is that for increasing LysoPC concentration there isa reduction in membrane tension, implying that estimations of membranetension based on spontaneous curvature assumptions may not be accurate. [ABSTRACT FROM AUTHOR]

Abstract: As a significant fraction of municipal solid waste, waste paper is a potential source for producing bioethanol. In the present paper, bioethanol production from various waste papers (newspaper, office paper, cardboard and magazine) using an enzyme complex (Cellic Ctec 1) was evaluated from an economic standpoint. Four bases cases without pre-treatment and two state-of-the-art cases (including dilute acid pre-treatment for office paper and oxidative lime pre-treatment for newspaper) were constructed using laboratory experimental data, literature values, expert consultations and simulation using AspenPlus™. Several scenarios were also carried out to assess the sensitivity of various technology parameters (i.e. solids loading in saccharification, anaerobic digestion and fermentation efficiency, and sugar yields in pre-treatment). The sensitivity analysis suggested that the economic performance of bioethanol produced from waste paper could be improved significantly with an up to 25% reduction in minimum ethanol selling price (MESP) by increasing solids loading in saccharification and with a 6% reduction in MESP by enhancing fermentation efficiency. The comparison of the bioethanol selling price at pump (reference year 2009) and the petrol price showed bioethanol produced from newspaper, office paper and cardboard were economically competitive with petrol. [Copyright &y& Elsevier]

Abstract: The effect of hydrostatic pressure on lipid structure and dynamics is highly important as a tool in biophysics and bio-technology, and in the biology of deep sea organisms. Despite its importance, high hydrostatic pressure remains significantly less utilised than other thermodynamic variables such as temperature and chemical composition. Here, we give an overview of some of the theoretical aspects which determine lipid behaviour under pressure and the techniques and technology available to study these effects. We also summarise several recent experiments which highlight the information available from these approaches. [Copyright &y& Elsevier]

Research into the folding mechanisms of integral membrane proteins lags far behind that of water-soluble proteins, to the extent that the term protein folding is synonymous with water-soluble proteins. Hydrophobic membrane proteins, and particularly those with transmembrane α-helical motifs, are frequently considered too difficult to work with. We show that the stored curvature elastic stress of lipid bilayers can be used to guide the design of efficient folding systems for these integral membrane proteins. The curvature elastic stress of synthetic phosphatidylcholine/phosphatidylethanolamine lipid bilayers can be used to control both the rate of folding and the yield of folded protein. The use of a physical bilayer property generalises this approach beyond the particular chemistry of the lipids involved. [Copyright &y& Elsevier]

We report a detailed kinetic study of the folding of an α-helical membrane protein in a lipid bilayer environment. SDS denatured bacteriorhodopsin was folded directly into phosphatidylcholine lipid vesicles by stopped-flow mixing. The folding kinetics were monitored with millisecond time resolution by time-resolving changes in protein fluorescence as well as in the absorption of the retinal chromophore. The kinetics were similar to those previously reported for folding bacteriorhodopsin in detergent or lipid micelles, except for the presence of an additional apoprotein intermediate. We suggest this intermediate is a result of the greater internal two-dimensional pressure present in these lipid vesicles as compared to micelles. These results lay the groundwork for future studies aimed at understanding the mechanistic origin of the effect of lipid bilayer properties on protein folding. Furthermore, the use of biologically relevant phosphatidylcholine lipids, together with a straightforward rapid mixing process to initiate the folding reaction, means the method is generally applicable, and thus paves the way for an improved understanding of the in vitro folding of transmembrane α-helical proteins. [Copyright &y& Elsevier]

ABSTRACT: The effects of biological buffers on lipids have not been fully investigated because of the long-standing assumption that these buffers are too hydrophilic to substantially interact with the lipid membrane. We present evidence that for some buffers, this is not necessarily the case. Our research points toward a membrane softening effect caused by the buffer molecules interacting with the headgroup region of the lipid. Changes in the elastic properties of the membrane are known to control membrane protein behavior; this work serves as a warning for the design of assays utilizing model membranes in the presence of buffers. [ABSTRACT FROM AUTHOR]

Monoacylglycerol based lipids are highly important modelmembranecomponents and attractive candidates for drug encapsulation and asdelivery agents. However, optimizing the properties of these lipidsfor applications requires a detailed understanding of the thermodynamicfactors governing the self-assembled structures that they form. Here,we report on the effects of hydrostatic pressure, temperature, andwater composition on the structural behavior and stability of inverselyotropic liquid crystalline phases adopted by monolinolein (an unsaturatedmonoacylglycerol having cis-double bonds at carbonpositions 9 and 12) under limited hydration conditions. Six pressure–temperaturephase diagrams have been determined using small-angle X-ray diffractionat water contents between 15 wt % and 27 wt % water, in the range10–40 °C and 1–3000 bar. The gyroid bicontinuouscubic (QIIG) phase is formed at low pressureand high temperatures, transforming to a fluid lamellar (Lα) phase at high pressures and low temperature via a region of QIIG/Lαcoexistence. Pressure stabilizesthe lamellar phase over the QIIGphase; at fixedpressure, increasing the water content causes the coexistence regionto move to lower temperature. These trends are consistent throughoutthe hydration range studied. Moreover, at fixed temperature, increasingthe water composition increases the pressure at which the QIIGto Lαtransition takes place. We discussthe qualitative effect of pressure, temperature, and water contenton the stability of the QIIGphase. [ABSTRACT FROM AUTHOR]

Mechanical properties of biological membranes are known to regulate membrane protein function. Despite this, current models of protein communication typically feature only direct protein-protein or protein-small molecule interactions. Here we show for the first time that, by harnessing nanoscale mechanical energy within biological membranes, it is possible to promote controlled communication between proteins. By coupling lipid-protein modules and matching their response to the mechanical properties of the membrane, we have shown that the action of phospholipase A2 on acyl-based phospholipids triggers the opening of the mechanosensitive channel, MscL, by generating membrane asymmetry. Our findings confirm that the global physical properties of biological membranes can act as information pathways between proteins, a novel mechanism of membrane-mediated protein-protein communication that has important implications for (i) the underlying structure of signaling pathways, (ii) our understanding of in vivo communication networks, and (iii) the generation of building blocks for artificial protein networks. [ABSTRACT FROM AUTHOR]

A response by Brian H. Davison, Arthur J. Ragauskas, Richard Templer, Timothy J. Tschaplinski, and Jonathan R. Mielenz to a letter to the editor about their article "The Path Forward for Biofuels and Biomaterials," in the January 27, 2006 issue is presented.

A high pressure cell for small and wide-angle x-ray diffraction measurements of soft condensed matter samples has been developed, incorporating a fully automated pressure generating network. The system allows both static and pressure jump measurements in the range of 0.1–500 MPa. Pressure jumps can be performed as quickly as 5 ms, both with increasing and decreasing pressures. Pressure is generated by a motorized high pressure pump, and the system is controlled remotely via a graphical user interface to allow operation by a broad user base, many of whom may have little previous experience of high pressure technology. Samples are loaded through a dedicated port allowing the x-ray windows to remain in place throughout an experiment; this facilitates accurate subtraction of background scattering. The system has been designed specifically for use at beamline I22 at the Diamond Light Source, United Kingdom, and has been fully integrated with the I22 beamline control systems. [ABSTRACT FROM AUTHOR]

Abstract: The lyotropic phase behaviour of two analogues of dioctadecyl dimethylammonium chloride was investigated. Both the inclusion of ester groups and subsequent minor structural rearrangement of the interfacial region of the surfactant were found to increase the chain melting temperature, although the overall phase behaviour remained similar for both compounds. Both of the two analogues were found to underswell, due to the formation of multi-lamellar vesicles. We also found that the inclusion of these ester linkages substantially reduced the metastability of the ‘gel phase’ in which the surfactants usually reside, accelerating the rate of collapse to a coagel state. This occurred via a nucleation-growth mechanism, where the growth was found to be one-dimensional, i.e. needle-like. [Copyright &y& Elsevier]

In this paper, we report on a novel osmotic cell, developed to simultaneously subject a sample to osmotic stress and measure structural changes by small angle x-ray diffraction. The osmotic cell offers many advantages over more conventional methods of osmotically stressing soft materials to measure their structural response. In particular, a full osmotic analysis can be performed with a single small sample (25 μl). This reduces sample handling and the associated systematic errors, as well as enabling tight control and monitoring of the thermodynamic environment during osmosis, thereby increasing measurement precision. The cell design enables control of osmotic pressure to ±0.04 bar over a pressure range of 1–100 bar, and temperature control to ±0.05 °C. Under these conditions, the lattice spacing in lyotropic structures was resolved to better than ±0.005 Å. Using the osmotic cell, we demonstrate good agreement with previous conventional measurements on the energy of dehydrating the fluid lamellar phase of dioleoylphosphatidylcholine in water. [ABSTRACT FROM AUTHOR]

Abstract: Membrane lipids are increasingly being recognised as active participants in biological events. The precise roles that individual lipids or global properties of the lipid bilayer play in the folding of membrane proteins remain to be elucidated, Here, we find a significant effect of phosphatidylglycerol (PG) on the folding of a trimeric α helical membrane protein from Escherichia coli diacylglycerol kinase. Both the rate and the yield of folding are increased by increasing the amount of PG in lipid vesicles. Moreover, there is a direct correlation between the increase in yield and the increase in rate; thus, folding becomes more efficient in terms of speed and productivity. This effect of PG seems to be a specific requirement for this lipid, rather than a charge effect. We also find an effect of single-chain lyso lipids in decreasing the rate and yield of folding. We compare this to our previous work in which lyso lipids increased the rate and yield of another membrane protein, bacteriorhodopsin. The contrasting effect of lyso lipids on the two proteins can be explained by the different folding reaction mechanisms and key folding steps involved. Our findings provide information on the lipid determinants of membrane protein folding. [Copyright &y& Elsevier]

Abstract: Phosphatidylglycerol (PG) is an anionic lipid commonly found in large proportions in the cell membranes of bacteria and plants and, to a lesser extent, in animal cells. PG plays an important role in the regulation and determination of the elastic properties of the membrane. Using small angle X-ray scattering experiments, we obtain that the monolayer spontaneous curvature of dioleoylphosphatidylglycerol (DOPG) is −1/150±0.021nm−1 when measured in 150mM NaCl. When the experiments are carried out in 150mM NaCl and 20mM MgCl2, the value obtained for the monolayer spontaneous curvature is −1/8.7±0.037nm−1. These values are of importance in modelling the effects of curvature elastic stress in membrane lipid homeostasis in the bacterium Acholeplasma laidlawii [Alley, S.H., Barahona, M., Ces, O., Templer, R.H., in press. Biophysical regulation of lipid biosynthesis in the plasma membrane. Biophys. J.] and indicate that divalent cations can play a significant role in altering curvature elastic stress. [Copyright &y& Elsevier]

We have used X-ray diffraction and differential scanning calorimetry (DSC) to study the structure and lyotropic phase behaviour of two synthetic dialkyl glycolipids having β-D-glucose and β-D-galactose headgroups and two saturated tetradecyl (C 14 ) chains. The diastereomeric compounds, 1,2-di-O-tetradecyl-3-O-(β-D-glucopyranosyl)-sn-glycerol (di-14:0-β-D-GlcDAG) and 1,2-di-O-tetradecyl-3-O-(β-D-galactopyranosyl)-sn-glycerol (di-14:0-β-D-GalDAG) show striking differences in their phase behaviour, particularly in the ordered lamellar phase region. Both compounds adopt the fluid lamellar L α phase upon cooling from the H II phase, but below the chain-melting transition,di-14:0-β-D-GlcDAG forms a metastable L β gel phase, whereas di-14:0-β-D-GalDAG forms only crystalline lamellar phases, on the timescale of our measurements. We have determined the limiting hydrations of the various phases, and compare the findings from these glycolipids with those from our previous studies of the phospholipid didodecyl phosphatidylethanolamine (di-12:0-PE). [ABSTRACT FROM AUTHOR]

Biomass represents an abundant carbon-neutral renewable resource for the production of bioenergy and biomaterials, and its enhanced use would address several societal needs. Advances in genetics, biotechnology, process chemistry, and engineering are leading to a new manufacturing concept for converting renewable biomass to valuable fuels and products, generally referred to as the biorefinery. The integration of agroenergy crops and biorefinery manufacturing technologies offers the potential for the development of sustainable biopower and biomaterials that will lead to a new manufacturing paradigm. [ABSTRACT FROM AUTHOR]

The lipidic cubic phase of monoolein has proved to be a matrix well suited to the production of three-dimensional crystals of membrane proteins. It consists of a single continuous bilayer, which is contorted in three-dimensional space and separates two distinct water channels. It has previously been proposed that on the addition of precipitants, membrane proteins embedded in the cubic phase migrate through the matrix to nucleation sites and that this process is dependent upon the stability of the lipidic cubic phase. Here, the effect of detergent type (C[sub 8]-C[sub 12] glucosides, C[sub 8]-C[sub 12] maltosides and C[sub 7] thiogluco- side) and concentration (1-3x the critical micelle concentration; CMC) on cubic phase stability are reported in the form of the temperature-dependent phase behaviour (268-313 K) in 40% aqueous solution. The results are tabulated to show the best monoolein (MO)-detergent mixtures, mixing temperatures and crystallization temperatures identified. Monooleindetergent mixtures suited for low-temperature in cubo crystallization of temperature-sensitive proteins are also reported for the first time. These mixtures can be prepared at low temperatures (mixed at ≤288 K) and remain stable at 277 K for a period of at least one month. They include MOheptyl thioglucoside (1x and 3x CMC), MO-nonyl glucoside (3x CMC), MO-octyl maltoside (3x CMC), MO-nonyl maltoside (1 x CMC) and MO-decyl maltoside (1 x CMC). [ABSTRACT FROM AUTHOR]

A preface to the "Journal of Renewable & Sustainable Energy" is presented.