1 INTRODUCTION Cellulose is the most abundant renewable biopolymer available in nature, which has the potential to contribute to meeting the demand for high quality biodegradable polymers, which are replacing the petroleum derived non-biodegradable polymers with an escalating environmental demand. Cellulose is a high molecular weight biopolymer having a long straight chain of linked sugar molecules bonded through β (1-4) glucosidic bond as shown in Figure 1.1(Habibi et al., 2010; Xu et al., 2013; Zhou & Wu, 2012). Though cellulose is the major structural component of the primary cell wall of plant, it is also found in bacteria, fungi, algae and even in animals. Cellulose is known to exist in six different polymorphic structures such as cellulose …show more content…
Cellulose chains are composed of both crystalline and amorphous regions. Breaking of the amorphous portion of cellulose chain is carried out by acid hydrolysis to yield crystalline residue that is CNCs. Hydrolysis largely disintegrates the acetal linkage in amorphous part of cellulose chain while due to long exposure to acid crystalline part may also degrade (Bondeson et al., 2006). Depending on the origin of the cellulose, CNCs of different width and length have been prepared and reported by different researchers. The aspect ratio (length to width ratio) of CNCs have been observed to vary between 10 and 30 for cotton and it lies around 70 for tunicate, a sea animal (Habibi et al., 2010). CNCs of various shapes viz. rod like (Habibi et al., 2010), spherical (Wang et al., 2008) and elliptical (Lu et al., 2012) have been obtained using different acid system and different cellulose origin. Sulphuric acid is the most commonly used acid for hydrolysis of cellulose to synthesize CNCs (Kim et al., 2001; Kupiainen et al., 2012; Lalia et al., 2013; Lu et al., 2012). The presence of bisulphite ion along with H+ ions results in better cellulose hydrolysis in sulphuric acid as compared to non-sulphur acid species like formic acid (Kupiainen et al., 2012). Hydrolysis using sulphuric acid leads to the introduction of charged sulphate ester groups to the surface CNC s (Abitbol et al., 2013; Lu & Hsieh, 2010). These sulphate groups attached to the CNC surfaces results in decreasing the thermal degradation temperature of CNCs (Jiang et al., 2010). To improve the thermal stability of CNCs, hydrochloric acid has been used as hydrolysing agent for hydrolysis of cellulose (Yu et al.,
Starch, cellulose, glycogen, and chitin are all examples of polysaccharides. According to the BIO 1510 Lab Manual (2016) polysaccharides are not very soluble in water but can be made to go into solution through heating or agitation. Polysaccharides are excellent energy storage molecules because they are easily built and broken down by enzymes. Forming fairly compact structures, polysaccharides allow energy storage without the space required by a pool of free glucose monomers. Other polysaccharides form strong fibers that provide protection and structural support in both plants and animals. (Carbohydrates.” Home,
After reading a number of articles, and attending the “Picking Cotton” lecture. I have come to the conclusion that, without the breakthrough of DNA extraction technology. Many people would still be convicted of a crime they never committed.
steps to obtain pure xylose. Moreover, the yield of xylitol is only 50 % of
Angela Lakwete. Inventing the Cotton Gin: Machine and Myth in Antebellum America. Baltimore: Johns Hopkins University Press, 2003.
Elizabeth Rolfes Per. -.. 12 12/13/15 Cotton “This machine may be turned by water or with a horse, with the greatest ease, and one man and a horse will do more than fifty men with the old machine. It makes labor fifty times less, without throwing any class of people out of business.” - Eli Whitney, 1793. In 1793, a new technology swept through the South, completely transforming the region and the culture of those who inhabited it.
Jennifer Thompson-Cannino was raped at knife point in her apartment. She was able to escape and identify Ronald Cotton as her attacker. The detective conducting the lineup told Jennifer that she had done great, confirming to her that she had chosen the right suspect. Eleven years later, DNA evidence proved that the man Jennifer Identified, Ronald Cotton was innocent and wrongfully convicted. Instead, Bobby Poole was the real perpetrator. Sadly, there are many other cases of erroneous convictions. Picking cotton is a must read for anybody because it educates readers about shortcomings of eyewitness identification, the police investigative process and the court system.
Investigating the Effect of Sugar Solution on the Weight and Size of Potato Cells Aim: To investigate whether the different concentration of sugar solution will affect the weight and size of the potato cells. General background information: Osmosis is defined as the movement of water or any other solution's molecules from an area in which they are highly concentrated to a region in which they are less concentrated. This movement must take place across a partially permeable membrane such as a cell wall, which lets smaller molecules (E.g. water) through but does not allow larger solute molecules to pass through. The molecules will continue to diffuse until the area in which the molecules are found to reach a state of equilibrium, meaning that the molecules are equally distributed throughout the cell, with no area having a higher or lower concentration than any other hence equal. Hypothesis/prediction: For this particular investigation I believe that the lower the concentration of the sugar solution in the test tube the mass of the potato will be greater and the longer the potato cells will be.
Enzymes, such as cellulases, which catalyse the breakdown of cellulose, have been isolated from several different organisms, including fungi. However, the purification of enzyme from these sources is expensive, on the order of $5.50 per gallon of ethanol produced. Genetic engineering or biotechnology has already played a key enabling role in the development of cellulosic biomass conversion technologies by dramatically reducing the cost of cellulase production from about $5.50 per gallon of ethanol to $0.10-15 per gallon of
Plant carbohydrates mainly include celluloses, gums and starches. The physical properties of starch grains influence the digestibility and processing qualities of tropical root and tubers. In addition to starch and sugar, root crops also contain some non-starch polysaccharides; including celluloses, pectins and hemicelluloses, as well as other associated structural proteins and lignins, which are collectively referred as dietary fibre. The protein content and quality of tropical roots and tubers (Table 1.6) is
The preparation of making wood into a pulp for papermaking is accomplished in two different ways. In the groundwood process, blocks of wood are held against a fast revolving grindstone that shreds off short wood fibbers from the block. The fibbers produced by this process are short and are used only in the production of cheap newsprint and used to be added with other types of wood fibber in the making of high-quality paper. Another technique uses a chemical-solvent processes where wood chips are treated with solvents that remove “resinous material and lignin” from the wood, leaving pure fibbers of cellulose.
present at all times but it must retain some of them. All plant life on Earth benefits from the ability of water to make a hydrogen bond with another substance of similar electronegative charge. Cellulose, the substance that makes up cell walls and paper products, is a hydrophilic substance ("water-loving"). It interacts with water but, unlike other hydrophilic substances, it will not dissolve in it. Cellulose can form strong hydrogen bonds with water molecules. This explains why a paper towel will "wick" water upwards when it comes in contact with it.
Polymer composite materials are widely used in industries like aircraft, automotive and submarine due to their great mechanical and thermal properties. But, the polymer and synthetic materials are non- biodegradable. Therefore the use and manufacturing of these materials will have harmful effect on environment. In contrast, natural fibers are renewable, biodegradable and environmentally friendly materials. Cellulose fibre has been applied as reinforced polymer composite in building, bridge construction and automotive [7].
A solution for making these processes eco-friendly is to use biotechnology [168]. Wool carbonization consists in the elimination of the cellulosic residues present on the raw wool. It is usually performed with concentrate sulfuric acid delivering strong acidic wastewaters. The use of enzymes in this process represents a possibility to diminish pollution as well as the water and energy consumed. According literature, partial carbonization with cellulolytic enzymes has been realized [169]. Other studies involving Cellulases have
With the depletion of fossil fuel resources comes speculations and debates about alternative energy sources. The world, including the Philippines, is practically dependent on a dwindling non-renewable source of energy. Today, experts are debating about and considering three options: Nuclear, Solar, or Wind Energy. Everyone has been accustomed to the bad image of nuclear energy as a result of the Chernobyl and Fukushima incidents above all others. The popular belief is that radiation from a nuclear meltdown is very harmful to humans and other living things—which is true—and that nuclear power plants are very dangerous and not ideal—which is not. According to Smith, et. al (n.d), all the nuclear disasters that ever occurred were caused by human error and natural disasters like tsunamis, not one because of system failure. Putting the false beliefs aside, with proper engineering and adequate maintenance by experts, a nuclear power plant is a very ideal and viable source of energy for the following reasons:
Some of the characteristics of Nata de coco are chewy, translucent, jelly-like and it is an indigenous dessert. On top of that, Nata de coco is most commonly sweetened as a candy or dessert, and can accompany many things including pickles, drinks, ice cream, puddings and fruit mixes. It is produced by the bacterial fermentation of coconut water. Nata de coco is produced by the fermentation of coconut water or coconut milk, which gels through the production of microbial cellulose by Acetobacter xylinus. Acetobacter xylinum is the most efficient and widely used cellulose-producing bacterium in fermenting the coconut water to produce the nata de coco. Chemical purities are one of the most important features of microbial cellulose, which distinguishes it from that of plants and is usually associated with hemicelluloses and lignin. Interesting properties of microbial cellulose allow nata de coco to con...