Biofuels—from cellulose munching bacteria
With the rising prices of oil affecting the economies of many countries, there is a growing need for alternative sources of fuel. Certain types of bacteria with an appetite for cellulose may provide the answer. Cellulose happens to be the most common organic compound on our planet. Cotton is about 90 per cent cellulose while wood contains up to 50 per cent cellulose. Indeed, plant matter comprises about 33 per cent cellulose, since it is the main component of the primary cell wall of green plants.
Cellulose consists of linear chains of hundreds or thousands of linked glucose units. Much effort has been successfully exerted to convert cellulose into biofuels such as ethanol in the past but the challenge has been to do so economically. This is because it is more difficult to break down cellulose into its component sugar units than starch, because of the manner the glucose units in it are linked together.
Now a breakthrough has been made by scientists at US department of energy's BioEnergy Science Center (BESC) who have succeeded in converting cellulose directly into isobutanol using a genetically modified strain of a cellulose—degrading microbe (Clostridium cellulolyticum). Isobutanol is a more desirable biofuel because it can be used directly in car engines without any engine modification and has similar heat value as standard petrol. Once the product is successfully developed commercially, you may be driving cars on a biofuel produced from grass.Miniature cameras
Scientists at the Fraunhofer Institute in Germany have developed an extremely small video camera which is no bigger than a grain of salt. This tiny camera can be used to peer into the various internal organs. It is also so inexpensive that it need not be sanitised after each use but it can be thrown away and replaced with a new one. Such ‘endoscopes’, as they are called, normally use fibre optic cables but the camera developed uses a normal electrical cable. The new system is expected to be commercialised by next year.
Next computer revolution—from graphene?
We have all heard of graphite. It comprises layers of carbon stacked together and arranged in a honeycomb pattern. If one peels off layers from it which are a few atoms thick, one obtains the material ‘graphene’ that possesses remarkable properties. The 2010 Nobel Prize for physics was awarded to Andre Geim and Konstantin Novoselov for their ground breaking work on the two-dimensional structure of graphene. The material shows remarkable electron mobility, with the electrons being able to zip across the surface at dazzling speed. James Tour at Rice University in Houston, Texas and coworkers have now developed a way of etching these sheets of atoms, so that portions of the material with a single layer can be formed that behaves like a metal to perform the functions of a wire. If a portion of graphene is etched differently so that a double layer is formed, it behaves as a semiconductor that can be transformed to a transistor.
Precise control in the manner the etching is carried out can thus lead to the development of super-fast computers of tomorrow.
Stem cells—the new exciting horizon of medicine
An exciting new rapidly developing field in medicine is that involving the use of stem cells to repair damaged organs. Stem cells found in human beings are of two broad types—embryonic stem cells and adult stem cells. Stem cells along with certain other cells act to repair damaged tissues in the body since they can be transformed (‘differentiated’) into other types of cells in the body. They can also be grown by cell culture and then transformed into various types of cells such as nerve, skin or intestinal cells.
In an important recent development, it has been found possible to induce the selective release of various types of stem cells from the bone marrow by the use of certain drugs. Thus, instead of providing patients with stem cells from different donors, (in which case there may be problems associated with rejection), the patient’s own stem cells can be selectively released from the bone marrow. These can then help in the repair and regeneration of specific tissues, depending on which type of stem cell is released. This ability to selectively stimulate the release of a patient’s own stem cells represents a major breakthrough in this rapidly developing field.
The work carried out by Prof Sara Rankin of Imperial College London and coworkers could lead to the development of new treatments for the repair of damaged heart tissue, and accelerate the repair of broken bones and ligaments.