Our other glucose energy source is cellulose, but we can’t eat it directly. For example, wood is cellulose. And while termites and animals can eat it for energy, humans cannot. Although humans cannot eat cellulose as a food source, we can eat animals that do, providing us with cellulose benefits (fiber) and the resulting benefit of glucose units we get from its consumption.
Cellulose is an essential substance that derived from glucose and is the main constituent of plant cell walls and of vegetable fibre. This straight chain polymer aligned side by side and stabilised by hydrogen bonds between hydroxyl groups forming a strong intermolecular bonds. Because of these hydrogen bonds cellulose is extremely tough and inflexible. In fact, when describing the structure of cellulose microfibrils, chemists call their arrangement “crystalline,” meaning that the microfibrils have crystal-like properties. Although starch has the same basic structure as cellulose, it is also a polysaccharide, the glucose subunits are bonded in such a way that allows the starch molecule to twist. In other words, the starch molecule is flexible, while the cellulose molecule is rigid.
Cellulose or mineral fibers are typically used in SMA mixtures. Cellulose fibers added at a rate of 0.3 percent by weight are made from paper stock and absorb the AC to some extent. Mineral fibers added at a rate of 0.2 percent by weight are extruded basalt or slag. Rock wool slag fibers are hard and not used in SMA. Application rate is typically 4 – 8 lbs./ton or 0.2 to 0.4% of the mix. Fibers can be added in pellet form or in bulk. However, it is essential that they be well mixed and separated before being uniformly distributed in the asphalt plant. High performance gravimetric fiber mixing systems are available for sale or rent to asphalt paving contractors.
Cellulose is a carbohydrate of high molecular weight, forming the solid structure of vegetable matter. It is contained in cotton in almost a pure state. Cellulose not elsewhere specified or included, in primary forms, falls in this heading.
Cellulose, the complex carbohydrate within plant cell walls, has potential to be a significantly more efficient fuel source. Present in all plant tissues, cellulose is more abundant than starch, but much of it is tightly bound to a rigid, glue-like material called “lignin.” That makes it difficult to extract, says Nathan Mosier, assistant professor of agricultural and biological engineering, who develops pretreatment techniques to liberate more cellulose for fermentation.
Cellulose can be regenerated from the ionic liquid solution in a range of structural forms with a relatively homogeneous microscopic morphology (Figure 2) by simply contacting the cellulosic solution with water. This allows, a simple, benign system for the processing of cellulose into fibers, monoliths and membranes and has potential environmental and cost advantages over current processing methodologies, which make use of volatile organic solvents. We will compare solvents traditionally used for cellulose dissolution with ionic liquids, and describe methods for cellulose regeneration. Results from regenerated cellulose, as well as important intermolecular forces will be discussed.
Cellulose is a polysaccharide consisting of a linear chain of several hundred to over ten thousand linked D-glucose units. It provides the structure of the cell wall in green plants. Cellulose can be hydrolyzed into its glucose units by treating it with concentrated acids at high temperature. Alternatively, enzymes such as the endo-acting cellulase break cellulose down into individual glucose units. HPLC using an Agilent Hi-Plex Ca column analyzes the breakdown products of an enzymic digestion of cellulose.
Cellulose is synthesized by plasma membrane-bound cellulose synthase complexes found in some bacteria, slime moulds, some alveolates, chromists, in red and green algae, embryophytes and tunicates. Cellulose is degraded by many heterotrophic bacteria and fungi to soluble saccharides for use in growth and energy production. Bacterial, fungal and nematode plant pathogens use cellulases to gain access to the contents of plant cells by digesting their walls, and in embryophytes, cellulases have a role in cell wall development and differentiation.