High-solid digestion - A comparison of completely stirred and plug-flow reactor systems.

High-solid digestion (HSD) for biogas production is a resource-efficient and sustainable method to treat organic wastes with high total solids content and obtain renewable energy and an organic fertiliser, using a lower dilution rate than in the more common wet digestion process. This study examined the effect of reactor type on the performance of an HSD process, comparing plug-flow (PFR) type reactors developed for continuous HSD processes, and completely stirred-tank reactors (CSTRs) commonly used for wet digestion. The HSD process was operated in thermophilic conditions (52 °C), with a mixture of household waste, garden waste and agricultural residues (total solids content 27-28 %).

Improved bioenergy value of residual rice straw by increased lipid levels from upregulation of fatty acid biosynthesis.

Background: Rice (Oryza sativa) straw is a common waste product that represents a considerable amount of bound energy. This energy can be used for biogas production, but the rate and level of methane produced from rice straw is still low. To investigate the potential for an increased biogas production from rice straw, we have here utilized WRINKLED1 (WRI1), a plant AP2/ERF transcription factor, to increase triacylglycerol (TAG) biosynthesis in rice plants.

Co-substrate composition is critical for enrichment of functional key species and for process efficiency during biogas production from cattle manure.

Cattle manure has a low energy content and high fibre and water content, limiting its value for biogas production. Co-digestion with a more energy-dense material can improve the output, but the co-substrate composition that gives the best results in terms of degree of degradation, gas production and digestate quality has not yet been identified. This study examined the effects of carbohydrate, protein and fat as co-substrates for biogas production from cattle manure.

High-resolution structure of a fish aquaporin reveals a novel extracellular fold.

Aquaporins are protein channels embedded in the lipid bilayer in cells from all organisms on earth that are crucial for water homeostasis. In fish, aquaporins are believed to be important for osmoregulation; however, the molecular mechanism behind this is poorly understood. Here, we present the first structural and functional characterization of a fish aquaporin; cpAQP1aa from the fresh water fish climbing perch (<i>Anabas testudineus</i>), a species that is of high osmoregulatory interest because of its ability to spend time in seawater and on land.

Influence of cysteine, serine, sulfate, and sulfide on anaerobic conversion of unsaturated long-chain fatty acid, oleate, to methane.

This study aims to elucidate the role of sulfide and its precursors in anaerobic digestion (i.e., cysteine, representing sulfur-containing amino acids, and sulfate) on microbial oleate conversion to methane.

TIRF Microscopy-Based Monitoring of Drug Permeation Across a Lipid Membrane Supported on Mesoporous Silica.

There is an urgent demand for analytic approaches that enable precise and representative quantification of the transport of biologically active compounds across cellular membranes. In this study, we established a new means to monitor membrane permeation kinetics, using total internal reflection fluorescence microscopy confined to a ≈500 nm thick mesoporous silica substrate, positioned underneath a planar supported cell membrane mimic. This way, we demonstrate spatiotemporally resolved membrane permeation kinetics of a small-molecule model drug, felodipine, while simultaneously controlling the integrity of, and monitoring the drug binding to, the cell membrane mimic.

Inoculum Source Determines Acetate and Lactate Production during Anaerobic Digestion of Sewage Sludge and Food Waste.

Acetate production from food waste or sewage sludge was evaluated in four semi-continuous anaerobic digestion processes. To examine the importance of inoculum and substrate for acid production, two different inoculum sources (a wastewater treatment plant (WWTP) and a co-digestion plant treating food and industry waste) and two common substrates (sewage sludge and food waste) were used in process operations. The processes were evaluated with regard to the efficiency of hydrolysis, acidogenesis, acetogenesis, and methanogenesis and the microbial community structure was determined.

Protein-Containing Lipid Bilayers Intercalated with Size-Matched Mesoporous Silica Thin Films.

Proteins are key components in a multitude of biological processes, of which the functions carried out by transmembrane (membrane-spanning) proteins are especially demanding for investigations. This is because this class of protein needs to be incorporated into a lipid bilayer representing its native environment, and in addition, many experimental conditions also require a solid support for stabilization and analytical purposes. The solid support substrate may, however, limit the protein functionality due to protein-material interactions and a lack of physical space.

Mesoporous silica nanoparticles with controllable morphology prepared from oil-in-water emulsions.

Mesoporous silica nanoparticles are an important class of materials with a wide range of applications. This paper presents a simple protocol for synthesis of particles as small as 40nm and with a pore size that can be as large as 9nm. Reaction conditions including type of surfactant, type of catalyst and presence of organic polymer were investigated in order to optimize the synthesis.

Trace element and temperature effects on microbial communities and links to biogas digester performance at high ammonia levels.

Background: High levels of ammonia and the presence of sulphide have major impacts on microbial communities and are known to cause operating problems in anaerobic degradation of protein-rich material. Operating strategies that can improve process performance in such conditions have been reported. The microbiological impacts of these are not fully understood, but their determination could help identify important factors for balanced, efficient operation.