New research by scientists at the University of Bristol has challenged one of the key axioms in biology - that enzymes need water to function. The breakthrough could eventually lead to the development of new industrial catalysts for processing biodiesel.
Enzymes are large biological molecules that catalyse thousands of different chemical reactions that are essential for all life, from converting food into energy, to controlling how our cells replicate DNA.
Throughout this diverse range of biological environments in which enzymes perform their various roles, the only constant is an abundance of water.
However, new findings published today [6 October] in Nature Communications, show that water is not essential for enzymes to fulfil their biological role.
This discovery could pave the way for the development of new thermally robust industrial enzymes that could be utilised in harsh processing conditions, with applications ranging from detergent technologies to alternative energies via biofuel production.
A group of scientists in Chile has created* artificial biomembranes, mimicking those found in living organisms on silicon surfaces, a step toward creating bio-silicon interfaces, where biological “sensor” molecules can be printed onto a cheap silicon chip with integrated electronic circuits.Described in The Journal of Chemical Physics from AIP Publishing, the artificial membranes have potential applications such as detecting bacterial contaminants in food, toxic pollution in the environment, and dangerous diseases .The idea is to create a “biosensor that can transmit electrical signals through the membrane,” said María José Retamal, a Ph.D. student at Pontificia Universidad Católica de Chile and first author of the paper.Lipid membranes separate distinct spaces within cells and define walls between neighboring cells — a functional compartmentalization that serves many physiological processes, protecting genetic material, regulating what comes in and out of cells, and maintaining the function of separate organs.Synthetic membranes that mimic nature offer the possibility of containing membrane proteins — biological molecules that could be used for detecting toxins, diseases and many other biosensing applications.More work is needed to standardize the process by which proteins are to be inserted in the membranes, to define the mechanism by which an electrical signal would be transmitted when a protein binds its target, and to calibrate how that signal is detected by the underlying circuitry, Retamal said. -------------------------------------------------------* Retamal and her colleagues created the first artificial membrane without using solvents on a silicon support base. They chose silicon because of its low cost, wide availability and because its “hydrophobicity” (how much it repels water) can be controlled chemically, allowing them to build membranes on top.Next they evaporated a chemical known as chitosan onto the silicon. Chitosan is derived from chitin, a sugar found in the shells of certain crustaceans, like lobsters or shrimp. Whole bags of the powder can be bought from chemical companies worldwide. They chose this ingredient for its ability to form a moisturizing matrix. It is insoluble in water, but chitosan is porous, so it is capable of retaining water.Finally they evaporated a phospholipid molecule known as dipalmitoylphosphatidylcholine (DPPC) onto the chitosan-covered silicon substrate and showed that it formed a stable “bilayer,” the classic form of a membrane. Spectroscopy showed that these artificial membranes were stable over a wide range of temperatures.
Via Dr. Stefan Gruenwald
Floating cities are nothing new. In the early 1960s, Buckminster Fuller designed a city – Triton – that was intended to float off the coast of Tokyo Bay. It was later considered but never commissioned by the US government.
“Three-quarters of our planet Earth is covered with water, most of which may float organic cities,” Fuller explains in his book Critical Path. “Floating cities pay no rent to landlords. They are situated on the water, which they desalinate and recirculate in many useful and non-polluting ways.”
Fifty years on, with heavy pollution causing climate change and rising sea levels, Fuller’s floating city concept is being seriously considered as an antidote to those problems.
For locals participating in the Pecan Street Demonstration in Austin’s suburban town of Mueller, TX, residential carbon footprint data is about as available as square footage. Their home utility consumption is monitored by the Pecan Street Research Institute at The University of Texas-Austin a
Today, the journal Science published the latest development in Michael Grätzel’s laboratory at EPFL: producing hydrogen fuel from sunlight and water. By combining a pair of solar cells made with a mineral called perovskite and low cost electrodes, scientists have obtained a 12.3 percent conversion efficiency from solar energy to hydrogen, a record using earth-abundant materials as opposed to rare metals.
The race is on to optimize solar energy’s performance. More efficient silicon photovoltaic panels, dye-sensitized solar cells, concentrated cells and thermodynamic solar plants all pursue the same goal: to produce a maximum amount of electrons from sunlight. Those electrons can then be converted into electricity to turn on lights and power your refrigerator.
At the Laboratory of Photonics and Interfaces at EPFL, led by Michael Grätzel, where scientists invented dye solar cells that mimic photosynthesis in plants, they have also developed methods for generating fuels such as hydrogen through solar water splitting. To do this, they either use photoelectrochemical cells that directly split water into hydrogen and oxygen when exposed to sunlight, or they combine electricity-generating cells with an electrolyzer that separates the water molecules.
By using the latter technique, Grätzel’s post-doctoral student Jingshan Luo and his colleagues were able to obtain a performance so spectacular that their achievement is being published today in the journal Science. Their device converts into hydrogen 12.3 percent of the energy diffused by the sun on perovskite absorbers – a compound that can be obtained in the laboratory from common materials, such as those used in conventional car batteries, eliminating the need for rare-earth metals in the production of usable hydrogen fuel.
“Soon after reporting on the 2010 BP oil spill, Naomi Klein discovered that she was pregnant – and miscarried. Was there a connection? She looks at the 'greenwashing' of big business and its effects”
Via Raphael Souchier
The study of a super-hydrophobic surface has led to discovery of a method for generating power from condensation. Condensing water droplets literally leap off the surface and produce an electric charge that can be harvested.